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As per CBSE Sample Paper, Issued On 02 Sep 2021..., , Sample, Papers, Science, CBSE Class 10 (Term I ), , Visit https://telegram.me/booksforcbse for more books.

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Contents, þ One Day Revision, , 1-13, , þ The Qualifiers, , 14-36, , þ CBSE Question Bank, , 37-39, , þ Latest CBSE Sample Paper, , 40-59, , Sample Paper 1, , 63-81, , Sample Paper 2, , 82-101, , Sample Paper 3, , 102-118, , Sample Paper 4, , 119-137, , Sample Paper 5, , 138-154, , Sample Paper 6, , 155-172, , Sample Paper 7, , 173-192, , Sample Paper 8, , 193-210, , Sample Paper 9, , 211-229, , Sample Paper 10, , 230-248, , Watch Free Learning Videos, Video Solutions of CBSE Sample Papers, Chapterwise Important MCQs, CBSE Case Based MCQs, CBSE Updates, Much more valuable content will be available regularly

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Syllabus, Science CBSE Class 10 (Term I ), Units, , Unit I, , Marks, , Chemical Substances-Nature and Behaviour, Chapter : Chemical Reactions and Equations, Chapter : Acids, Bases and Salts, Chapter : Metals and Non-metals, , Unit II, , World of Living, Chapter : Life Processes, , Unit III, , Natural Phenomena, Chapter, , : Light : Reflection and Refraction, , Chapter, , : Human Eye and Colourful World, , THEME MATERIALS, , THEME THE WORLD OF THE LIVING, , Unit I Chemical Substances - Nature, and Behaviour, , Unit II World of Living, , Chapter - Chemical Reactions and Equations, Chemical Reactions : Chemical equation, balanced, chemical equation, implications of a balanced, chemical equation, types of chemical reactions:, combination, decomposition, displacement, double, displacement, precipitation, neutralisation,, oxidation and reduction., , Chapter - Life processes, Life Processes : Living Being. Basic concept of, nutrition, respiration, transport and excretion in, plants and animals., , THEME HOW THINGS WORK, Unit III Natural Phenomena, , Chapter - Acids, Bases and Salts, Acids, Bases and Salts : Their definitions in terms of, furnishing of H+ and OH ions, general properties,, examples and uses, concept of pH scale Definition, relating to logarithm not required , importance of, pH in everyday life; Preparation and uses of sodium, hydroxide, bleaching powder, Baking soda, Washing, soda and plaster of Paris., , Chapter Light Reflection and Refraction, Reflection of light by curved surfaces; Images, formed by spherical mirrors, centre of curvature,, principal axis, principal focus, focal length, mirror, formula Derivation not required , magnification., Refraction; Laws of refraction, refractive index., Refraction of light by spherical lens; Image formed, by spherical lenses; Lens formula Derivation not, required ; Magnification. Power of a lens., , Chapter - Metals and Non metals, Metals and Non-metals : Properties of metals and, non-metals; Reactivity series; Formation and, properties of ionic compounds., , Chapter Human Eye and Colourful World, Refraction of light through a prism, dispersion of, light, scattering of light, applications in daily life.

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MCQs Preparation Tips, Focus on Theory, , Learn to Identify Wrong Answers, , MCQs can be formed from any part or, line of the chapter. So, strong command, on theory will increase your chances to, solve objective questions correctly and, quickly., , The simplest trick is, observe the options, first and take out the least possible one, and repeat the process until you reach, the correct option., , Practice of Solving MCQs, Cracking an MCQ-based examination, requires you to be familiar with the, question format, so continuous practice, will make you more efficient in solving, MCQs., , Speed & Accuracy, In MCQ-based examination, you need, both speed and accuracy, if your, accuracy is good but speed is slow then, you might attempt less questions, resulting in low score., , Analyse your Performance, During the practice of MCQs you can, identify your weak & strong, topics/chapter by analysing of incorrect, answers, in this way you will get an, awareness about your weaker topics., , Practice through Sample Papers, Solving more & more papers will make, you more efficient and smarter for, exams. Solve lots of Sample Papers, given in a good Sample Papers book., , Attempting MCQs in Exams, 1. Read the paper from beginning to, end & attempt those questions first in, which you are confident. Now move, on to those questions which requires, thinking and in last attempt those, questions for which you need more, attention., , 2. Read instructions of objective, questions carefully and find out what, is being asked,, a bit carelessness can lead you to, incorrect answer., , 3. Tick/Write down the correct option, only while filling the OMR sheet., , Step by step solution is not required, in MCQ type questions, it is a waste, of time, you will not get extra marks, for this., , 4. Most of the time, you need not to, solve the MCQ completely to get the, correct option. You can start thinking, in reverse order and choose the best, fit option., , 5. As there is no negative marking for, incorrect answers, so don't leave any, question unanswered. Use your, guess if you have not exact idea, about the correct answer.

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1, , CBSE Sample Paper Science Class X (Term I), , ONE DAY, , REVISION, Revise All the Concepts in a Day, Just Before the Examination..., , ●, , Chemical Reactions and Equations, , Chemical Reaction, , 2. Decomposition Reaction, , A chemical reaction is a change in which one or more, substance(s) or reactant(s) react(s) to form new, substance(s) with entirely different properties., 2Na(s) + 2H2O(l ), Sodium, , Water, , 2NaOH(aq) + H2(g), Sodium, hydroxide, , ¯, , e.g., , Hydrogen, , Products, , Chemical Equation, A chemical equation is the symbolic representation of a, chemical reaction. Symbols and formulae of the, reactants and products are used for the same., e.g. The reaction of burning of methane gas can be, written as:, D, CH 4 (g ) + 2O 2(g ) ¾®, CO 2(g ) + 2H 2O(l ), , Oxygen, , Carbon, dioxide, , Water, , Balanced Chemical Equation, A balanced chemical equation is that in which the total, number of atoms of each element are equal on both, sides of the equation. The balancing of a chemical, equation is based on law of conservation of mass., , The chemical reactions are classified into different, classes depending upon the type of chemical changes, taking place. These reactions are as follows:, 1. Combination Reaction, A reaction in which two or more reactants combine, to form a single product, is called combination, reaction., e.g. CaO(s) + H 2O(l ) ¾® Ca(OH)2( aq) + Heat, Water, , Heat, , CaCO 3 ¾® CaO(s) +, (Limestone), , CO 2(g ), , (Quick lime ) (Carbon dioxide), , Calcium hydroxide, (Slaked lime), , (i) Exothermic Reactions The reactions which are, accompanied by the evolution of heat, are called, exothermic reactions (combustion reaction)., e.g. respiration., (ii) Endothermic Reactions The reactions which occur, by the absorption of heat/energy (either in the form, of light or electricity), are called endothermic, reactions. Photosynthesis and decomposition, reactions are example of endothermic reaction., 4. Displacement Reaction, When a more reactive element displaces less reactive, element from its salt solution, it is called displacement, reaction. e.g., Fe(s) + CuSO 4 (aq ) ¾® FeSO 4 (aq ) + Cu(s), Iron, metal, , Copper sulphate, (Blue), , Ferrous sulphate, Or, Iron (II) sulphate, (Green), , Copper, metal, , 5. Double Displacement Reaction, The reaction in which two different ions or group of, atoms in the reactant molecules are displaced by each, other is called double displacement reaction. It is also, called precipitation reaction as precipitate is, produced in such reactions. e.g., Na 2SO 4 (aq ) + BaCl 2(aq ) ¾®, Barium, Sodium sulphate, BaSO 4 ¯ + 2 NaCl(aq ), chloride, Barium sulphate, (White ppt.), , Sodium, chloride, , ONE DAY REVISION, , Types of Chemical Reactions, , Calcium oxide, (Quick lime), , e.g., , 3. Exothermic and Endothermic Reactions, , Reactants, , Methane, , A reaction in which a single reactant breaks down to, form two or more products, is known as decomposition, reaction.

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02, , CBSE Sample Paper Science Class X (Term I), 6. Neutralisation Reaction, , e.g., CuO, Copper, oxide, , 2NaOH + H 2SO 4 ¾® Na 2SO 4 + 2H 2 O, , (Sodium, hydroxide), , (Sulphuric, acid), , (Sodium, sulphate), , O2, , Oxygen, , Heat, , ¾®, , 2CuO, , In which hydrogen is added/oxygen is removed, from the substance., e.g., , Potassium, chlorate, , Rancidity can be prevented by keeping food, materials in air-tight containers, packing of food, items in packets containing nitrogen gas instead of, air, by adding antioxidants, e.g. BHA (Butylated, Hydroxy Anisole) and BHT (Butylated Hydroxy, Toluene)., , Oxygen, , (iii) Redox Reactions Those reactions in which, oxidation and reduction take place simultaneously,, are called redox reactions., , ●, , H2 O, Water, , (ii) Rancidity It is the process of slow oxidation of oil, and fat (which are volatile in nature) present in the, food materials resulting in the change of smell and, taste in them., , D, ® 2KCl(s) + 3O 2(g ), 2KClO 3 (s) ¾¾, , Potassium, chloride, , +, , (i) Corrosion The phenomenon due to which metals, are slowly eaten away by the reaction of air, water, and chemicals present in the atmosphere, is called, corrosion., In case of Iron, this process is commonly known as, rusting of iron. The black coating on silver and the, green coating on copper are other examples of, corrosion., , Copper oxide, , (ii) Reduction It is a process in which a substance, gains electrons., Or, , Cu, Copper, , Hydrogen, , Effects of Oxidation in Everyday Life, , In which oxygen is added/hydrogen is removed, from the substance., +, , ¾¾®, Heat, , Oxidation, , (i) Oxidation It is a process in which a substance, loses electrons., Or, , Copper, , H2, , (Water), , 7. Oxidation and Reduction Reactions, , e.g. 2Cu, , +, , ®, , e.g., , Reduction, , ®, , The reaction in which acid or acidic oxide react with, base or basic oxide to form salt and water are called, neutralisation reactions., , Acids, Bases and Salts, , Acids, Substances which are sour in taste and turns blue, litmus to red are called acids., , Some naturally occurring acids are:, , Acids are also defined as those substances, which furnish hydrogen ion (H + ) or hydronium ion, (H 3O+ ) on dissociation or ionisation in an aqueous, solution., Chemical Properties of Acids, ● Acids form salts on reacting with most of the, metals with the evolution of hydrogen gas., e.g. Zn + H 2SO 4 ¾® ZnSO 4 + H 2 ­, , ONE DAY REVISION, , ●, , Acids reacts with metal carbonates and metal, hydrogen carbonates to produce salt, carbon dioxide, gas and water., e.g. CaCO 3 + 2 HCl ¾® CaCl 2 + H 2O + CO 2 ­, , ●, , Acids give salt and water on reaction with metallic, oxides (basic)., e.g., , ●, , CuO + 2 HCl ¾® CuCl 2 + H 2O, , Strong acids like (HCl, H 2SO 4 , HNO 3, etc.) are, completely ionised in water, while weak acids, (like H 2S, HCN, CH 3COOH, etc.) ionises partially in, water., , Natural source, , Acid, , Vinegar, , Acetic acid, , Orange and lemon, , Citric acid, , Tamarind, , Tartaric acid, , Tomato, , Oxalic acid, , Curd, , Lactic acid, , Ant sting and nettle sting, , Methanoic acid, , Bases or Alkalies, Substances that furnish hydroxide ions (OH - ) on, dissociation or ionisation in an aqueous solution are, called bases. They are bitter in taste and soapy to touch, and turn red litmus paper into blue., Chemical Properties of Bases, ● Strong bases react with active metals to produce, hydrogen gas., ●, , e.g., Zn + 2 NaOH ¾® Na 2ZnO 2 + H 2 ­, Oxides of non-metal (acidic) on reaction with base, give salt and water., e.g., , CO 2 + Ca (OH )2 ¾® CaCO 3 + H 2O

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03, , CBSE Sample Paper Science Class X (Term I), , ●, , ●, , Strong bases (like NaOH, KOH, Ca(OH)2, etc.) are, completely dissociated or ionised in water, whereas, weak bases (like NH 4OH, Al(OH)3, etc.) ionises only, partially., Strong bases (like NaOH, KOH, etc.) melt on heating, while weak bases (like NH 4OH, Mg(OH)2, etc.), decompose on heating., , (i) Olfactory Indicators Those substances whose, odour changes in acidic or basic medium are, called olfactory indicators. e.g. Vanilla extract and, onion., (ii) Universal Indicators To judge how strong a given, acid or base is, a universal indicator is used which, is a mixture of several indicators. It shows different, colours at different concentrations of hydrogen ion, in a solution., , Acids/Bases in Water Solution, In the presence of water, acids give H + ion. As H + ion, cannot exist alone, so it combines with water molecules, and form H 3O + (hydronium ion)., HCl + H 2O ¾® H 3O + + Cl -, , e.g., , H + + H 2O ¾® H 3O +, In the same way, in presence of water, bases give, OH - ion., H2O, NaOH(s) ¾®, Na + (aq ) + OH - (aq ), Both acids and bases produce electric current in their, aqueous solutions due to the presence of free ions., Reaction Between Acids and Bases, Acids react with bases to produce salt and water. This, reaction is known as neutralisation reaction., Base + Acid ¾¾® Salt + Water, Mixing of an acid or base with water is called dilution., Dissolving an acid or base in water is highly exothermic, (heat generating) reaction. So, care must be taken, while doing it., , Indicators, Indicators are the substances that change their colour, or odour when added into an acid or alkaline solution., Indicators can be classified as natural indicators,, synthetic indicators, olfactory indicators and universal, indicators., (i) Natural Indicators These indicators are found in, nature in the plants. e.g. Litmus solution is a, purple colour dye extracted from the lichen plant., (ii) Synthetic Indicators The indicators which are, synthesised in the laboratory or industry are, known as synthetic indicators. e.g. Methyl orange,, phenolphthalein., Colour, Indicator, , pH-range, , (In Basic, Medium), , Natural Indicators, Litmus, , –, , Red, , Blue, , Turmeric, , –, , Yellow, , Red, , Red cabbage, juice (from leaves), , –, , Red, , Green, , Synthetic Indicators, Phenolphthalein, Methyl orange, , 8.4-10.00 Colourless, 3.1-4.4, , Red, , Pink (Red), Yellow, , The acids and bases having more ionisation property, (produced larger number of H + or OH - ions) are, called strong acid and strong base, respectively. In the, same way, the acids and bases which shows less, tendency of ionisation are called weak acid and weak, base, respectively., pH Scale, It is a scale used for measuring hydrogen ion, concentration. It has values ranging from 0 (very acidic), to 14 (very alkaline)., Thus, pH is a number which indicates the acidic or, basic nature of a solution., Higher the hydronium ion concentration present in the, solution, lower is its pH value [pH means power of, hydrogen ions]., ● If pH > 7, solution is basic., ● If pH < 7, solution is acidic., ● If pH = 7, solution is neutral., 0, , Acidic nature increasing, H, , Neutral, 7, , Basic nature increasing, , +, OH, +, , Increase in H ion, concentration, , 14, , –, , +, Decrease in H ion, concentration, , Variation of pH with the change in, concentration of H+ (aq) and OH- (aq) ions, , Importance of pH in Everyday Life, ● Our body works normally within a pH range of, 7.0 to 7.8., ● When pH of rain water goes below 5.6, it is called, acid rain. It lowers the pH of the river water and, makes survival of aquatic life difficult., ● Nature of soil is known by testing its pH and then a, particular crop is grown in it by selecting suitable, fertilizer., ● During indigestion, the stomach produces too much, acid, it causes pain and irritation. To correct the, disturbed pH range, milk of magnesia (a mild, base) is used as a medicine, which is also called, antacid., ● If the pH inside the mouth decreases below 5.5, (acidic), the decay of tooth enamel begins. The, bacteria present in the mouth degrades the sugar, , ONE DAY REVISION, , (In Acidic, Medium), , Strength of Acid and Base

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04, , CBSE Sample Paper Science Class X (Term I), , ●, , and left over food particles. To prevent tooth decay,, toothpastes (basic) are used which neutralise the, excess acid., When insects like honeybee, ant, etc., bite, they inject, an acid into the skin, that causes pain and irritation. If, a mild base like baking soda is applied on the, affected area, it gives relief., , Salts, Salts are produced by the neutralisation reaction, between acid and base., , (iii) Baking Soda, Chemical Name, , – Sodium hydrogen carbonate or, sodium bicarbonate., , Common Name, , – Baking soda, , Molecular Formula – NaHCO 3, It is prepared by using sodium chloride as one of the, raw material., NaCl (aq ) + H 2O (l ) + CO 2 (g ) + NH 3 (g ), Brine, , Carbon, dioxide, , ¾® NH 4Cl (g ) + NaHCO 3(s), , Acid + Base ¾® Salt + Water, Salts of strong acid and a strong base are neutral with, pH value of 7., Salts of a strong acid and weak base are acidic with pH, value less than 7. Salts of strong base and weak acid, are basic in nature with pH value more than 7., Common Salt [Sodium Chloride (NaCl)], Common salt is formed by the combination of, hydrochloric acid and sodium hydroxide solution. It is, obtained on large scale from sea water by separating, other salts from it., Common salt is an important raw material for various, materials of daily use, like sodium hydroxide, baking, soda, washing soda, bleaching powder, etc., , 2NaCl ( aq ) + 2H 2O ( l ), Sodium chloride Water, , Electric current, ¾¾¾¾®, , 2NaOH( aq ), Sodium hydroxide, , + Cl 2(g ) + H 2(g ), Chlorine, (At anode), , Hydrogen, (At cathode), , (ii) Bleaching Powder, – Calcium hypochlorite or calcium, oxychloride or chlorite of lime or, chlorinated lime., – Bleaching powder, , ONE DAY REVISION, , Molecular Formula – Ca(OCl)Cl or CaOCl 2, It is produced by the action of chlorine on dry slaked, lime., D, Ca(OH)2 + Cl 2 ¾¾, ® CaOCl 2 + H 2O, Chlorine, , Bleaching, powder, , Sodium, hydrogen, carbonate, , Chemical Name, , – Sodium carbonate, , Common Name, , – Soda ash or crystalline sodium, carbonate, , Molecular Formula – Na 2CO 3 ×10H 2O, Sodium carbonate can be obtained by heating baking, soda. The recrystallisation of sodium carbonate gives, washing soda. It is also a basic salt., 2 NaHCO 3, , Heat, , ¾® Na 2CO 3 + H 2O + CO 2 ­, ( Water ) (Carbon, (Sodium, dioxide), carbonate), , (Sodium hydrogen, carbonate ), , Na 2CO 3 (s) + 10H 2O(l ) ¾® Na 2CO 3 .10H 2O ( s), ( Washing soda ), , – Calcium sulphate hemihydrate, , Common Name, , It is prepared by the process called chlor-alkali process., , Slaked, lime, , (iv) Washing Soda, , Chemical Name, , Chemical Name – Sodium hydroxide, Common Name, – Caustic soda, Molecular Formula – NaOH, , Common Name, , Ammonium, chloride, , (v) Plaster of Paris, , (i) Caustic Soda, , Chemical Name, , Ammonia, , – Plaster of Paris, 1, Molecular Formula – CaSO 4 × H 2O, 2, 3, 1, 373 K, CaSO 4 × 2H 2O ¾ ¾ ¾® CaSO 4 × H 2O + H 2O, Heat, 2, 2, Gypsum, Plaster of Paris, , Plaster of Paris is a white powder and on mixing with, water, it changes to gypsum giving a hard solid mass., This is called setting of plaster of Paris. This reaction is, exothermic in nature., 1, 3, CaSO 4 × H 2O + H 2O ¾® CaSO 4 × 2H 2O, 2, 2, (Gypsum), (Plaster of Paris), , Water of Crystallisation, Crystals of some compounds seem to be dry (or, anhydrous) but actually contain, some water, molecules attached to them. These water molecules, are called water of crystallisation and such salts are, called hydrated salts.

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05, , CBSE Sample Paper Science Class X (Term I), , ●, , Metals and Non-Metals, , On the basis of properties, elements can be divided into, two main groups, i.e. metals and non-metals. Apart, from these, some elements show properties of both, metals and non-metals. These are called metalloids., , Metals, Those elements which form positive ions by losing, electrons are called metals. e.g. copper, iron, aluminium,, sodium etc., Physical Properties of Metals, The various physical properties of metals are as follows, (i) Hardness Most of the metals are hard. Some alkali, metals like lithium, sodium and potassium are so, soft that they can be easily cut with a knife., (ii) Ductility It is the property due to which a metal can, be drawn into thin wires. Gold is the most ductile, metal., (iii) Malleability It is the property of metal due to which it, can be beaten into thin sheets. Gold and silver are, the most malleable metals., (iv) Electrical conductivity The conduction of, electricity or flow of electric current occurs due to, the flow of free electrons present in the metal., (v) Good conductor of heat Generally metals are, good conductors of heat, except lead and mercury,, which are poor conductors of heat. Metals like, copper and silver are the best conductors of heat., (vi) Melting and boiling points Metals generally have, high melting and boiling points. Tungsten has the, highest melting point among metals, while gallium, and caesium have very low melting points., These two metals will melt if we keep them on our, palm., (vii) Sonority The metals that produce a sound on, striking a hard surface are said to be sonorous., Note All metals (except mercury) exist as solid at room, temperature., , Chemical Properties of Metals, Most of the chemical properties of metals are due to, their electropositive nature. It means metal atom loses, electrons to form cations., ¾® M n+ + ne -, , (Metal atom), 1. Reaction of Metals with Oxygen, (Burning in Air or Formation of Oxides), , Almost all metals combine with oxygen (or air) to form, metal oxides, which are basic in nature., Metal + Oxygen ¾® Metal oxide, , 2. Reaction of Metals with Water, Metals react with water and produce a metal oxide and, hydrogen gas. Metal oxides that are soluble in water, dissolves in it further to form metal hydroxide., Metal + Water ¾® Metal oxide + Hydrogen gas, Metal oxide + Water ¾® Metal hydroxide, e.g., , + 2H 2O(l ) ¾® 2KOH(aq ) + H 2(g ), , 2K(s), Potassium, , (Cold), , Potassium, hydroxide, , Hydrogen, , + Heat, , Ca(s) + 2H 2O(l ) ¾® Ca(OH)2(aq ) +, Calcium, , Water, (cold), , Calcium, hydroxide, , H 2 (g ), Hydrogen, (less violent), , 3. Reaction of Metals with Acids, (i) Reaction of metals with dil. HCl Except a few less, reactive metals (such as Cu, Hg, Ag, Au, Pt etc), all, metals react with dilute sulphuric acid and, hydrochloric acid to produce salt and hydrogen, gas., Metal + Dilute acid ¾¾® Salt + Hydrogen, (ii) Reaction of metals with dil. HNO3 Hydrogen gas, is not evolved when a metal reacts with nitric acid., This is due to strong oxidising nature of nitric acid. It, oxidises the H 2 produced to water and itself get, reduced to any of the nitrogen oxide (N 2O, NO, NO 2 )., But magnesium (Mg) and manganese (Mn) react, with very dil. HNO 3 to evolve H 2 gas., Metal + HNO 3 ¾® Salt + NO 2 / N 2O ­ + H 2O, (Dil.), , Exceptional case (Only for Mn and Mg), Metal (Mn/Mg) + HNO 3 ¾® Salt + H 2 ­, (Dil.), , Note Aqua-regia (Latin for ‘royal water’), It is a freshly prepared mixture of concentrated, hydrochloric acid and concentrated nitric acid in, the ratio of 3 : 1., , 4. Reaction of Metals with, Solutions of Other Metal Salts, Reactive metals can displace a comparatively less, reactive metal from its compounds in aqueous salt, solution or in molten form., Metal A + Salt solution of B ¾® Salt solution of A +, Metal B, This type of reaction is called displacement reaction., , ONE DAY REVISION, , M, , Exception Some metal oxides such as aluminium, oxide, zinc oxide show both acidic and basic, behaviour. These are called amphoteric oxides.

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06, , CBSE Sample Paper Science Class X (Term I), Chemical Properties of Non-metals, , The Reactivity Series of Metals, On the basis of their relative tendency to lose electron, and their reactive nature, metals are arranged in a series,, this series is called activity series or reactivity series of, metals., Reactivity Series (activity series) of Metals, , These, metals, are less, reactive, than, hydrogen, , Potassium, , Na, , Sodium, , Ca, , Calcium, , Mg, , Magnesium, , Al, , Aluminium, , Zn, , Zinc, , Fe, , Iron, , Sn, , Tin, , Pb, , Lead, , H, , Hydrogen, , Cu, , Copper, , Hg, , Mercury, , Ag, , Silver, , Au, , Gold, , (Most reactive metal), , But on heating, readily form oxides or salts with conc., acids., Heat, , S(s) + 2H 2SO 4 (conc. ) ¾® 3SO 2(g ) + 2H 2O(l ), S(s) + 6 HNO 3(conc. ) ¾Heat, ¾¾® H 2SO 4 (aq ), +, , Non-metals also show displacement reaction like metals., , ( Least reactive metal ), , Non-metals, Those elements which form negative ions by gaining, electrons are called non-metals, e.g. iodine, sulphur,, oxygen, hydrogen etc. The non-metals are either solids, or gases except bromine which is a liquid., , e.g. Cl 2 (g ) + 2NaBr (l ) ¾® 2NaCl (l ) + Br2 (g ), Sodium, bromide, , Chlorine, , The various physical properties of metals are as follows :, (i) Malleability and ductility Non-metals are neither, malleable nor ductile, i.e. they cannot be beaten into, thin sheets or drawn into wires., (ii) Brittleness Non-metals are brittle in nature., For instance, sulphur is a brittle solid. If it is, hammered, it breaks into pieces., (iii) Physical state Most of the non-metals are soft, (if solid). Only diamond, an allotropic form of carbon, is the hardest known substance., (iv) Lustre Non-metals do not have lustre, i.e. shining, surface. However, diamond, graphite (the, allotropic forms of carbon) and iodine have lustre., (v) Electrical and thermal conductivity Non-metals are, generally poor conductors of heat and electricity., Graphite, an allotrope of carbon, is a good, conductor of electricity., (vi) Melting and boiling points Generally, non-metals, have low melting and boiling points. But non-metals, that are solids have comparatively higher boiling, points, e.g. B, Si, C etc., , Sodium, chloride, , Bromine, , Reaction between Metals and Non-Metals, (Ionic Bond Formation), Metals have a tendency to loose electrons to form, cations (+ve ions) and non-metals have a tendency to, gain electrons to form anions (-ve ions)., When metals and non-metals react with each other, then both of them tries to achieve completely filled, outermost shell by the transfer of electrons., This type of chemical bond formed by the complete, transfer of electrons from one atom to another is, called ionic bond. Such compounds are called ionic, compounds., For example, Na ¾¾®, , (2,8,1), , Physical Properties of Non-metals, , ONE DAY REVISION, , 6 NO 2(g ) +2H 2O(aq ), , (Reddish, brown vapour), , Decreasing chemical reactivity, , These, metals, are more, reactive, than, hydrogen, , K, , Non-metals do not react with water, steam or dilute, acids to evolve hydrogen gas., , Cl + e - ¾¾®, , (2,8,7), ·, , ´´, , Na +, , (2,8), (Sodium cation), , + e-, , Cl -, , (2,8,8), (Chloride anion), ´´, , + · ´´, ´ ¾® [Na ][ ´ Cl ´ ], Na +´ Cl, ´´, ´´, , Properties of Ionic Compounds, (i) Physical nature Ionic compounds are hard, crystalline solids because of strong forces, of attraction between the positive and negative, ions., (ii) Melting and boiling points These compounds, have high melting and boiling points, (iii) Solubility These compounds are soluble in water, (polar solvent) and insoluble in organic solvents, (non-polar solvent) like kerosene, benzene, ether,, petrol etc., (iv) Conduction of electricity Ionic or electrovalent, compounds are good conductors of electricity, but, they conduct electricity either in molten form or in their, aqueous solution.

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07, , CBSE Sample Paper Science Class X (Term I), , ●, , Life Processes, , I. Nutrition, All life processes require energy to carry out their, functions. This energy is obtained from carbon-based, food sources through the process called nutrition., There are two modes of nutrition, i.e. autotrophic and, heterotrophic., , ●, , Autotrophic Mode of Nutrition, ●, , ●, , Autotrophic nutrition is performed by the autotrophs, that synthesis organic food in the form of, carbohydrates from carbon dioxide and water in the, presence of sunlight and chlorophyll to convert them, into stored forms of energy. This process of food, synthesis is known as photosynthesis. Examples of, autotrophs are green plants (producers) and some, bacteria., General reaction involved in process of, photosynthesis is, Sunlight, 6CO 2, + 12H 2O ¾ ¾ ¾ ¾, ¾® C 6H12O 6, Carbon dioxide, , Water, , Chlorophyll, , Nutrition in Human Beings, ●, , ●, , ●, , Carbohydrate, , + 6O 2 + 6H 2O, Oxygen, , ●, , Water, , ●, , Major events occurring in photosynthesis are, , (i) Absorption of light energy by chlorophyll., (ii) Conversion of light energy into chemical energy, (iii) Splitting of water molecules into hydrogen and, oxygen., (iv) Reduction of carbon dioxide to carbohydrates., Leaf in green plants have some structures known as, chloroplasts (containing chlorophyll) which are, the main site for the process of photosynthesis to, occur., ● Stomata are the tiny pores present on the surface of, leaves, through which gaseous exchange occurs for, photosynthesis. The opening and closing of the pore, is a function of guard cells., , Examples are fungi like yeast, bread moulds and, mushroom. Some organisms take food from other, organisms without killing them. These are called, parasites, i.e. Cuscuta, orchids, ticks, lice, leeches, and tapeworms., In Amoeba, digestion occurs in the food vacuole,, formed by the engulfing of food by its pseudopodia., The undigested food is moved to the surface of the, cell and thrown out., , ●, , ●, , ●, , ●, , In mouth, food is crushed into small particles, through chewing and mixed with saliva, which, contains amylase for digestion of starch., Food is swallowed and passes through the pharynx, and oesophagus to reach stomach. The gastric juice, contains pepsin (for digesting proteins), HCl and, mucus., Hydrochloric acid mainly provide an acidic, environment for the protein digestion by pepsin. The, mucus protects the lining of the stomach from the, action of the acid under normal conditions., Liver secretes bile which emulsifies fat. Pancreatic, juice contains enzymes amylase, trypsin and, lipase for digesting starch, proteins and fats,, respectively., In the small intestine, carbohydrate, proteins and fats, are completely digested into glucose, amino acids, fatty acids, gylcerol and respectively. The villi of small, intestine absorb the digested food and supply it to, every cell of the body., Herbivores have longer small intestine for cellulose, digestion., The undigested food is egested out from the body, through the anus. The exit of this waste material is, regulated by the anal sphincter., , Mouth/Buccal cavity, , Guard cells, , Oesophagus (food pipe), , Salivary glands, Tongue, Stomata pore, , Stomach, Liver, , Chloroplast, , (a), Open stomatal pore, , (b), Close stomatal pore, , Gall bladder, (stores bile), , Large intestine, (colon), , Heterotrophic Mode of Nutriton, ●, , ●, , Heterotrophs are organisms which are dependent on, other organisms for their food. The heterotrophs may, be herbivores, carnivores, parasites or saprophytes., Some organisms breakdown the food into basic, molecules outside their body then absorb them., , Rectum, , Bile duct, Appendix, Small intestine, , Human digestive system, , ONE DAY REVISION, , Pancreas, Diaphragm

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08, , CBSE Sample Paper Science Class X (Term I), , II. Respiration, , ●, , Respiration is the breaking down of nutrients to, release energy. During respiration, the digested, food materials are broken down to release energy in, the form of ATP., Depending on the requirement of oxygen, respiration, occurs by following two ways:, (i) Aerobic respiration, oxygen., , It occurs in presence of, , (ii) Anaerobic respiration, oxygen., , It occurs in absence of, , ●, , The alveoli provides a surface where the exchange of, gases can take place. The walls of the alveoli contains, an extensive network of blood-vessels. When we, breathe in, we lift our ribs and flatten our diaphragm and, the chest cavity becomes larger as a result. Because of, this, air is sucked into the lungs and fills the expanded, alveoli., The blood brings carbon dioxide from the rest of the, body for release into the alveoli, and the oxygen in, the alveolar air is taken up by blood in the alveolar, blood vessels to be transported to all the cells in the, body., , In both kinds of respiration, the first step is, breakdown of glucose into pyruvate. This process, takes place in cytoplasm., Absence of, oxygen, , In, cytoplasm, Glucose, (6-carbon, molecule), , Pyruvate, (3-carbon, molecule, +, Energy), , Ethanol, (in yeast), (2-carbon molecule), + Carbon dioxide, + Energy, Lack of oxygen, Lactic acid, (in our, (3-carbon molecules), muscle cells) + Energy, Presence of, oxygen, Carbon dioxide, (in, + Water + Energy, mitochondria), , Breakdown of glucose by various pathways, , Respiration in Plants, ●, , ●, , Plants respire through stomata, lenticels (present, on stem) and through the process of diffusion in, roots., In leaves, respiration takes place by diffusion of, oxygen through stomata into the cells of the leaf, from where carbon dioxide is released into the, atmosphere., , Respiration in Animals, ●, , ONE DAY REVISION, , ●, , ●, , ●, , ●, , The aquatic organisms (such as fishes etc), utilise the oxygen dissolved in water for, respiration. Aquatic organisms breathe more, rapidly (through mouth) to accumulate more and, more oxygen because the amount of dissolved, oxygen is fairly lower in water than the amount of, oxygen in the air., In terrestrial organisms, atmospheric oxygen is, used for respiration and this oxygen is absorbed, by different organs in different animals., In human beings, air is taken into the body, through the nostrils., From here, the air passes through the throat, into, the lungs. Rings of cartilage are present in the, throat, which ensures that the air passage does, not collapse., Within the lungs, the passage divides into smaller, and smaller tubes which finally terminates in, balloon-like structures, called alveoli., , Nasal passage, , Alveoli, , Mouth cavity, Pharynx, Larynx, , Trachea, Rings of, cartilage, , Lung, Bronchi, Respiratory, bronchioles Bronchioles, Diaphragm, Alveolar sac, , Ribs, , Human respiratory system, , Respiratory Pigment, Haemoglobin (which has very high affinity for oxygen) is, the respiratory pigment in human beings. It is mainly, responsible to carry oxygen from lungs to tissues, before, releasing it. It is also responsible for the red colour of Red, Blood Corpuscles (RBCs)., , III. Transportation, Transportation is a life process in which a substance, absorbed (or made) in one part of the body of an, organism is carried to other parts of the body through the, circulating fluids like blood and lymph., , Transportation in Human Beings, The transport system of human beings consists of a, circulating fluid called blood, which is pumped by a, muscular organ known as heart and a system of, interconnecting tubes, i.e. blood vessels., Heart, ● The heart acts like a pumping machine in our body that, pushes out the blood into the blood vessels., ● Human heart is four chambered, (i.e., two upper atria, (singular : atrium) and two lower ventricles)., ● Oxygen-rich blood from lungs comes to thin walled upper, chamber of the heart, left atrium which then contracts and, transfer blood to left ventricle., ● The left ventricle contracts and blood is pumped to the, body parts.

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09, , CBSE Sample Paper Science Class X (Term I), , ●, , ●, , Deoxygenated blood enters in right atrium and when it, contract, it transfers blood to right ventricle, it pumps, blood to the lungs for oxygenation., Ventricles have thick walls than atrium because they, have to pump blood into various organs., , ●, , ●, , ●, , Aorta, Pulmonary arteries, , Vena cava, from upper, body, , Pulmonary veins, , Right atrium, , Left atrium, , Maintenance by Platelets, Blood has platelet cells which circulate around the, body and plug the site of injury by forming a blood, clot., , ●, , Left ventricle, ●, , Septum, (dividing wall), , Sectional view of the human heart, , There are three types of vessels involved in blood, circulation; arteries, veins and capillaries, (i) Arteries The arteries have thick, muscular and elastic, walls which carry blood at high pressure. They do not, have valves. It carries blood away from the heart to, various organs of the body., , (ii) Veins The veins have thin walls than arteries which, carry blood at low pressure. They have valves, to prevent the back flow of blood. It collects the, blood from different organs and bring it back to the, heart., (iii) Capillaries Capillaries are formed when artery divides, into smaller tubes. The walls of capillaries are one cell, thick. Exchange of materials between blood and, surrounding thick cells takes place across the thin, walls of capillaries., ● Humans show double circulation and complete, separation of oxygenated and deoxygenated blood. In, double circulation, the blood passes through the heart, twice during each cycle., , ●, , Transportation in Plants, ●, , ●, , ●, , On the contrary, plants take simple compounds as, carbon dioxide and water and stored them as food, in leaves. Roots absorb raw materials, water and, minerals from soil., Xylem and phloem carry substances from one, part of the plant body to the another., Xylem transports water and minerals obtained from, the soil, whereas phloem (vascular tissue), transports products of photosynthesis from the, leaves to the other parts of the plant., , Transport of Water, ●, , ●, , ●, , There is a concentration gradient between roots, and soil, so, water moves into roots from soil and, creates a water column pushed upwards. Alone, pressure is not enough., Transport of water occurs also due to transpirational, pull., , Aorta to body, ●, , Capillaries in body, organs apart from the lungs, , Schematic representation of transport, and exchange of gases, , Transpiration is the loss of water in the form of, vapour from the aerial parts (i.e., stem, leaves) of, the plant. It takes place through the special pores, known as stomata., Transpiration helps in the absorption and upward, movement of water and minerals dissolved in it, from roots to the leaves., In day time, transpiration pull is the major driving, source in the movement of water in the xylem., , Transport of Food and Other Substances, ●, , Translocation is the phenomenon of transport or, movement or soluble products (sugar) from the, leaves to the other parts of the plant by the help of, phloem., , ONE DAY REVISION, , Pulmonary vein, from lungs, ●, , Vena cava, from body, , Apart from blood, lymph in our body is an another, type of fluid involved in transportation. This is also, called tissue fluid., Lymph drains into lymphatic capillaries from the, intercellular spaces, which join to form large lymph, vessels that finally open into larger veins., It is also meant to carry any digested and, absorbed fat from intestine and drains excess fluid, from extracellular space back into the blood., , Transpiration, , Lung, capillaries, Pulmonary, artery to lungs, , The force that blood exerts against the wall of a, vessel is called blood pressure., The normal systolic pressure is about 120 mm of, Hg and diastolic pressure is 80 mm of Hg., It is measured with an instrument called, sphygmomanometer., , Lymph, , Vena cava, from lower, body, Right, ventricle, , ●, , Blood Pressure

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10, , CBSE Sample Paper Science Class X (Term I), , ●, , ●, , Sugar like sucrose is transferred into phloem, tissue by the help of energy (ATP)., It occurs in sieve tubes with the help of, adjacent companion cells., , ●, , Bowman’s capsule, , ●, , Glomerulus, , Tubular part, of nephron, , Branch of, renal artery, , Excretion, ●, , The collecting duct finally gathers all the materials that has, not returned to the blood through the tubular membranes., , Excretion is the biological process by which, an organism removes the metabolic wastes, from the body., Unicellular organisms excrete waste by simple, process like diffusion, whereas multicellular, organisms use specialised organs for the, removal of waste products., , Renal artery, Branch of, renal vein, Collecting duct, Capillaries, , Excretion in Human Beings, ●, , In humans, a pair of kidneys, a pair of ureters,, urinary bladder and urethra constitutes the, excretory system., , Structure of a nephron, ●, , Left renal artery, Left renal vein, , ●, , Left kidney, , Aorta, Inferior vena, cava, , Right, ureter, , Urethra, , ●, , Haemodialysis, ●, , Urinary, bladder, ●, , Human excretory system, ●, , ●, , ●, , In case of kidney failure, an artificial kidney is used. It is a, device to remove nitrogen waste products from the blood, through the dialysis., It is different from natural kidney as the process of, reabsorption does not occur in artificial kidney., , Excretion in Plants, ●, , ●, , ●, , Plants give off gaseous wastes like carbon dioxide and, oxygen through stomata and lenticels during respiration, and photosynthesis., Plants also get rid of excess of water by the process of, transpiration and can also store waste substances in old, xylem such as resins and gums., Some plants store waste substances in the cell vacuoles, and get rid of them by dropping their leaves. e.g., deciduous, plants. While, other some plants also excrete some solid, waste substances into the soil around them., , Light : Reflection and Refraction, , Reflection of Light, , Laws of Reflection, , The phenomenon of bouncing back of light rays, on striking an opaque surface, is called, reflection of light., , fle, , r, , Re, , i, , ct, , ed, , ra, y, , Normal, , nt, de, ci y, In ra, , ONE DAY REVISION, , ●, , Each kidney has thousand of tiny tubules, called nephron i.e., filteration unit which are, closely packed together)., The urine is formed to filter out waste products, from the blood., The blood then passes through the tubular, part of nephron (where important or useful, substances such as glucose, amino acids,, fats and a major amount of water are, selectively reabsorbed by the tubular part) of, the nephron., , The urine formed in each kidney, then enters a long tube,, the ureter (which connects the kidneys with the urinary, bladder)., Urine is stored in the urinary bladder for sometime before, eliminating through urethra (an opening by which urine, passes out)., Pressure of the expanded bladder leads to the urge to pass, it out through the urethra., , Angle of incidence, , Angle of reflection, , Reflection from plane surface, , There are two laws of reflection:, (i) The incident ray, reflected ray and normal at the point, of incidence, all lie in the same plane., (ii) Angle of incidence is always equal to angle of, reflection, i.e. Ði = Ðr., , Spherical Mirror, It is the mirror which has spherical reflecting surface. They are, of two types:, (i) Convex mirror/diverging mirror The spherical mirror, with outward curved reflecting surface.

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11, , CBSE Sample Paper Science Class X (Term I), , (ii) Concave mirror/converging mirror The spherical, mirror with inward curved reflecting surface., Image Formation by Concave Mirror, Position of, Object, , Position of, Image, , At focus or in, the focal plane, , At infinity, , At the centre of, curvature, , At the centre, of curvature, , Real, inverted and, same, size as that of, object, , Between focus, and centre of, curvature, , Beyond the, centre of, curvature, , Real, inverted and, magnified, , At infinity, , Real,, inverted and, extremely, magnified, , Behind the, mirror, , Virtual, erect, and, magnified, , Image Formation by Convex Mirror, , Denser, , Denser, , r, , r, Refracted ray, , Refracted ray, , Refractive Index, m 2 represents refractive index of medium 2 with, respect to medium 1, when light is going from medium, 1 to medium 2., m, sin i, 1, m2 = 2 =, m 1 sin r, 1, , where, m 2 is called the absolute refractive index of, medium 2., Refraction through a Rectangular Glass Slab, When a light ray enters into a glass slab, then the, emergent ray is parallel to the incident ray but it is, shifted sideward slightly., , ra, , Virtual, erect, and extremely, diminished, , A, , N1, , Air, (rarer), , i, , y, , B, , r, Glass, slab, (denser), , d ra, acte, , r, , y, , Virtual, erect, and diminished, , Refr, , Between the, principal focus, and the pole,, behind the, mirror, , Nature and, Size of, Image, , (ii) Ratio of sine of angle of incidence to the sine of, angle of refraction for light of single wavelength is, constant for a given pair of media (Snell’s law), sin i, i.e., = m, constant (m or h), sin r, This constant is known as refractive index (m)., , D, , C, Air, (rarer), , e, Em, y, , Height of image (hi ) - v, =, Height of Object (h0 ) u, , Lens, , Lateral, displacement, , Refraction through glass slab, , It is a transparent medium bounded by two surfaces,, atleast one of which is curved., Lenses are of two types:, (i) Convex or converging lens A lens which is thicker, at the centre and thinner at its end is called convex, lens., , ONE DAY REVISION, , ra, , It is expressed as, , Magnification, , t, en, , 1 1 1, + =, v u f, where, u = object distance from pole of mirror, v = image distance from pole of mirror, and, f = focal length of mirror, , g, er, , N2, , Mirror Formula, , m=, , Rarer, , (i) The incident ray, the normal and the refracted ray,, all lie in the same plane., , nt, ide, , At the principal, focus, behind, the mirror, , Between infinity, and the pole, (i.e. at finite, distance), , i, , Rarer, , Inc, , Position of, Image, , At infinity, , i, , Laws of Refraction, Real, inverted and, diminished, , Position of, Object, , Incident ray, , Incident ray, , Real, inverted,, extremely, diminished, in size, , Between focus, and the centre, of curvature, , Between the, pole and focus, , The phenomenon of bending of light from its original, path on entering another medium of different density., , Nature and, Size of, Image, , Beyond the, centre of, curvature but at, finite distance, from mirror, , At the focus, , Refraction of Light

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12, , CBSE Sample Paper Science Class X (Term I), , Image Formation by a Concave Lens, , (ii) Concave or diverging lens A lens which is, thinner at the centre and thicker at its ends is, called concave lens., , Position of, Object, , Image Formation by a Convex Lens, Position of, Object, , Nature and Size, of Image, , At F2, , Beyond 2F1, (at finite, distance), , Between F2 and, 2 F2, , Real, inverted, and diminished, , At 2F1, , At 2F2, , Real, inverted, and of same size, as that of object, , Beyond 2F2, , Real, inverted, and, magnified, , At F1, , At infinity, , Real, inverted, and highly, magnified, , Between, lens and F1, , On same side of, the lens as the, object, , It is expressed as,, , 1 1 1, - =, v u f, , Magnification, Power of a Lens, , hi v, =, ho u, , The ability of a lens to converge or diverge light rays is, called power (P ) of the lens. It is defined as the, reciprocal of focal length,, 1, 100, i.e. P [in Dioptre (D )] =, =, f (in cm) f (in cm), For combination of lenses, P = P1 + P2 + P3 + …, , Human Eye and the Colourful World, , Refraction of Light through a Prism, , Angle of prism (A) A, G, , N, , D, i, , Inc, , ay, nt r, ide, , P, , E, Q, , H, , r, , r, N¢, , M¢, , e e, F, , A, , R (Red), , light, White, , of, Angle n (d), tio, devia, M, , O (Orange), Y (Yellow), G (Green), B (Blue), I (Indigo), V (Violet), , B, , C, , Dispersion of white light by a prism, Em, R, , erg, ent, r, , ay, , S, C, B, Refraction of light through a triangular glass prism, , Dispersion of White Light by a Glass Prism, ● The phenomenon of splitting of white light by prism, into its constituent colours is called dispersion of, white light., ● The group of different colours of light rays, produced by the prism due to dispersion is called, spectrum., , Recombination of White Light, Newton obtained white light using similar prism in, inverted position., P2, , A, , White light, , t, Sli, , R, V, Dispersion, P1, First prism, , Screen, , Recombination, R, light, R, White, V, , V, A, Second prism, , Recombination of spectrum of white light, , Spectrum of white light, , Prism is a transparent refracting medium bounded by, two plane surfaces, inclined to each other at a certain, angle. It has one triangular base and three rectangular, lateral surfaces., , ONE DAY REVISION, , Virtual, erect, and diminished, , Lens formula, , m=, , Virtual, erect and, magnified, , Virtual, erect, and highly, diminished, , Between focus, and optical, centre, on the, same side of lens, as object, , Anywhere, between, optical centre, and infinity, , At infinity, , Nature and Size, of Image, , At focus on same, side of lens as, object, , At infinity, , Real,, inverted and, extremely, diminished, , Between F1, and 2 F1, , ●, , Position of, Image, , Position of, Image

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13, , CBSE Sample Paper Science Class X (Term I), Rainbow, It is a natural spectrum appearing in the sky after a rain, shower. It is caused by dispersion of sunlight by tiny water, droplets, present in the atmosphere., Atmospheric Refraction, The refraction of light caused by the Earth’s, atmosphere, which consists of air layers of varying, optical densities, is called atmospheric refraction., Some phenomena based on atmospheric refraction, are:, (i) Twinkling of stars The twinkling of a star is due to, atmospheric refraction of star's light. The, continuously changing atmosphere refracts the, light by different amounts. In this way, the intensity, of star light reaching our eyes increases and, decreases continuously and the star appears to, twinkle at night., (ii) Advance sunrise and delayed sunset This is, because of atmospheric refraction. When the Sun is, slightly below the horizon, the Sun’s light coming, from less dense to more dense air, is refracted, downwards., Because of this, the Sun appears to be raised, above the horizon and so the rising Sun can be, seen about 2 min before actual sunrise. Similarly,, the Sun can be seen for about 2 min even after the, Sun has set below the horizon., , Scattering of Light, The reflection of light from an object in all directions is, called scattering of light. The colour of scattered light, depends upon the size of scattering particles and, wavelength of light., Some phenomena based on scattering of light are:, (i) Tyndall effect The scattering of light when it, passes through a colloidal solution is called Tyndall, effect. The Earth’s atmosphere is a heterogenous, mixture of minute particles of smoke, tiny water, droplets, suspended particles of dust and, molecules of air, which becomes visible due to, scattering of light., (ii) Colour of the sky During the day time sky appears, blue. This is because the size of the particles in the, atmosphere are comparable to the wavelength of, blue light, so they scatter the light of shorter, wavelengths (blue end of spectrum) and hence, the, sky appears blue., (iii) Colour of sun at sunrise and sunset At sunrise, and sunset, the sun appears red. . Near the horizon, most of the blue light and shorter wavelength is, scattered away by the particles of the size, comparable to these wavelengths. Therefore, the, light that reaches our eyes is of longer wavelength., This gives rise to the reddish appearance of Sun., , ONE DAY REVISION

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14, , CBSE Sample Paper Science Class X (Term I), , THE, , QUALIFIERS, Chapterwise Set of MCQs to Check Preparation, Level of Each Chapter, , 1. Chemical Reactions and Equations, Direction (Q. Nos. 1-15) Each of the question has four options out of which only one is correct., Select the correct option as your answer., , 1. The equation given below depicts which type of chemical reaction?, A + BC ¾® AC + B, (b) Combination, (d) Displacement, , (a) Combustion, (c) Decomposition, , 2. Identify the substance that is oxidised and the substance that is reduced in the, following reaction, CuO( s) + H 2 ( g) ¾® Cu( s) + H 2O( l), Oxidised, , Reduced, , (a), , CuO, , H2, , (b), , H2, , CuO, , (c), , H2O, , Cu, , (d), , Cu, , H2O, , 3. Salman took some copper turnings and added them to silver nitrate solution. What, would he observe?, (a) The solution turned blue, (c) White precipitate was formed, , (b) Yellow precipitate was formed, (d) The solution turned red, , 4. Identify gas A evolved at anode in the given setup., , THE QUALIFIERS, , Plastic mug, Test tube, Graphite, rod, Anode, Switch, , (a) Oxygen, , (b) Ozone, , Water, Rubber, stopper, Cathode, 6V, Battery, , (c) Hydrogen, , (d) Carbon dioxide

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CBSE Sample Paper Science Class X (Term I), , 5., , 15, , A white salt, X, , Residue, , Brown fumes, , Which of the following two combinations are correct?, 1. X - Reduction reaction, 2. X - Endothermic reaction, 3. X - Decomposition reaction, 4. X - Displacement reaction, (a) 1 and 2, (b) 2 and 3, (c) 3 and 4, (d) 1 and 4, , 6. Which of the following correctly represents a balanced chemical equation?, (a) 2HNO 3 + Ca(OH) 2 ¾® Ca(NO 3 ) 2 + 2 H 2O, (b) NaOH + H 2SO 4 ¾® Na 2SO 4 + 2H 2O, (c) NaCl + AgNO 3 ¾® 2 AgCl+ NaNO 3, (d) BaCl 2 + H 2SO 4 ¾® BaSO 4 + HCl, , 7. An element X on exposure to moist air turns reddish brown and a new compound Y is, formed. The substance X and Y are, X, , Y, , (a), , Fe, , Fe2 O3, , (b), , Cu, , CuO, , (c), , Ag, , Ag2 S, , (d), , Al, , Al 2 O3, , 8. Which of the following condition is necessary for a chemical reaction?, (a) It must be accompanied with change in temperature and pressure, (b) It must follow the law of conservation of mass, (c) It must be accompanied with change in state, (d) It must be accompanied with production of energy, , 9. Shivani performed a reaction in which the addition and removal of oxygen taken place, simultaneously. Choose the correct name for the reaction?, (a) Oxidation reaction, (b) Reduction reaction, (c) Redox reaction, (d) Precipitation reaction, , 10., , Limestone, P, Slaked lime, , Quick lime, , Identify the correct option from the given table which represents the type of reaction, occurring in step P and Q respectively., Endothermic, (a), (b), (c), (d), , P, O, P, O, , Exothermic, P, P, O, O, , THE QUALIFIERS, , Q

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16, , CBSE Sample Paper Science Class X (Term I), , 11. A substance added to food containing fats and oils to prevent rancidity is called., (a) Oxidant, , (b) Rust, , (c) Coolant, , (d) Antioxidant, , 12. The table shows below gives information about four different types of processes., S.No., , Name of process, , Word equation, , 1., , Combustion, , Hydrogen + Oxygen ¾® Water, , 2., , Photosynthesis, , Carbon dioxide + Water ¾ ¾¾¾® Glucose + Oxygen + Water, , Sunlight, , Chlorophyll, , Heat, , 3., , Combination, , Limestone ¾ ¾¾® Quick lime + Carbon dioxide, , 4., , Photodecomposition, , Silver bromide ¾ ¾¾® Silver + Bromine, , Light, , Identify the process that is correctly paired with its word equation., (a) 1 and 2, (b) 2 and 3, (c) 2 and 4, (d) 1 and 3, , 13. Which of the following statements about the given reaction are correct?, 3Fe( s) + 4 H 2 O ( g) ¾® Fe 3 O 4 ( s) + 4 H 2 ( g), (i) Iron metal is getting oxidised., (ii) Water is getting reduced., (iii) Water is acting as reducing agent., (iv) Water is acting as oxidising agent., (a) (i), (ii) and (iii), (b) (iii) and (iv), (c) (i), (ii) and (iv), (d) (ii) and (iv), , 14. Which of the following are exothermic processes?, (i) Reaction of water with quick lime, (iii) Evaporation of water, (a) (i) and (ii), (c) (i) and (iv), , (ii) Dilution of an acid, (iv) Sublimation of camphor (crystals), (b) (ii) and (iii), (d) (iii) and (iv), , 15. Na 2SO 4 + BaCl 2 ¾® BaSO 4 + 2NaCl, , THE QUALIFIERS, , Identify the correct option from the given table which represents the type of reactions, occuring in the given reaction., Double displacement reaction, , Precipitation reaction, , Oxidation, , (a), , P, , P, , P, , (b), , P, , P, , O, , (c), , P, , O, , P, , (d), , O, , P, , P, , Answers, 1. (d), 6. (a), 11. (d), , 2. (b), 7. (a), 12. (c), , 3. (a), 8. (b), 13. (c), , 4. (a), 9. (c), 14. (a), , 5. (b), 10. (a), 15. (b), , For Detailed Solutions, Scan the code

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17, , CBSE Sample Paper Science Class X (Term I), , 2. Acids, Bases and Salts, 1. A girl met with an accident and her leg get fractured. She went to an orthopedics for, treatment. The doctor mixed a white powder in water and applied it to her leg. What, could be the white powder is?, (a) Talcum powder, (b) Paris of plaster, (c) Plaster of Paris, (d) Copper phosphate, , 2. Identify the colour of wet blue litmus paper brought near the mouth of delivery tube in, the following experiment., Wet limus paper, , Delivery tube, Cork, Test tube, , Conc. H2SO4, NaCl, , (a) The litmus paper will turn red, (c) The litmus paper will turn green, , (b) The litmus paper will remain blue, (d) The litmus paper will dry, , 3. Aman added a few mL of conc. sulphuric acid to zinc granules. Which of the following, reaction takes place when metal zinc reacts with it?, (a) Zn + 2H 2SO 4 ¾® ZnSO 3 + 2 H 2O + 2SO 2, (b) Zn + 2H 2SO 4 ¾® Na 2ZnO 2 + H 2, (c) Zn + 2H 2SO 4 ¾® ZnSO 4 + SO 2 + 2H 2O, (d) Zn + H 2SO 4 ¾® ZnSO 4 + H 2, , 4. Consider the following reaction,, Iron (II), chloride, , B, Sodium, chloride, , A, , Hydrogen, Chloride, , C, D, , Ammonium, chloride, , Here, A, B, C and D respectively are, (a) A = Conc. HCl; B = Fe; C = NH 4 OH; D = PbO, (b) A = Conc. H 2SO 4 ; B = Fe; C = NH 4 OH; D = Pb(NO 3 ) 2, (c) A = Conc. H 2SO 4 ; B = Fe; C = NH 3 ; D = Pb(NO 3 ) 2, (d) A = Conc. HCl; B = Fe; C = NH 3 ; D = PbO, , THE QUALIFIERS, , Lead, chloride

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18, , CBSE Sample Paper Science Class X (Term I), , 5. On a pH scale, pH of blood is shown below., 0, , 1, , 2, , 3, , 4, , 5, , 6, , 7, , 8, , What is the nature of blood?, (a) Neutral, (c) Slightly alkaline, , 6., , 9, , 10 11 12 13 14, , (b) Highly alkaline, (d) Slightly acidic, , 14, 12, 10, pH 8, 6, 4, 2, 0, , A, , B, , C, , D, , The graph given below depicts the pH value of four different chemicals A, B, C and D., Which of the following is least acidic?, (a) A, (b) B, (c) C, (d) D, , 7. Seema added a few drops of ethanoic acid to solid sodium carbonate. What would she, observed?, (a) A separate layer of acid is formed, (c) A black precipitate was formed, , (b) A hissing sound was produced, (d) Brisk effervescence of CO 2 was observed, , 8. Which of the following compounds should be added to the beaker, so that the bulb, will glow?, , 6 volt battery, , Bulb, Switch, , Beaker, I., Nail, Solution of X, Rubber cork, , THE QUALIFIERS, , 1. Dilute HCl, 3. Glucose, Codes, (a) 1 and 2, , 2. Alcohol, 4. Lime water, (b) 1 and 4, , (c) 2 and 3, , (d) 2 and 4, , 9. The table shown below gives information about four substances A, B, C and D., Substance, , pH value, , A, , 8.7, , B, , 5.5, , C, , 1.7, , D, , 12.3

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19, , CBSE Sample Paper Science Class X (Term I), , Identify the basic compounds from the above given substances., (a) A and B, (b) B and C, (c) A and D, (d) C and D, , 10. A student adds a few drops of the universal indicator to a solution of dilute sodium, hydroxide acid in the way shown here. He would observe that the colour of the, solution changes from colourless to, , Drops of universal, indicator, , Dilute sodium hydroxide, solution, , (a) red, , (b) yellow, , (c) violet, , (d) green, , 11. On adding a few drops of universal indicator to three unknown colourless, solutions P, Q and R taken separately in three test-tubes shown in the following, diagrams. A student observed the changes in colour as green in P, red in Q and, violet in R., , (P), Green, , (Q ), Red, , (R), Violet, , Write the correct decreasing order of pH of the solutions., (a) P > Q > R, (b) Q > P > R, (c) R > Q > P, (d) R > P > Q, , 12. Which of the following is an incorrect match?, (a) Bleaching powder—CaOCl 2, (b) Caustic soda—NaOH, (c) Baking soda—NaHCO 3, (d) Washing soda—Na 2CO 3 × 4H 2O, , 13. Which of the following statements is correct regarding neutralisation reaction?, , 4. Common salt is formed by the process of neutralisation., Codes, (a) 1, 2, 4, (b) 1, 3, 4, (c) 2, 3, 4, , (d) 1, 2, 3, , THE QUALIFIERS, , 1. Salts are produced by the process of neutralisation between acid and base., 2. Oxygen and water are liberated as byproducts., 3. Salts of strong acid and strong base are neutral in nature.

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20, , CBSE Sample Paper Science Class X (Term I), , 14., At anode, , At cathode, , H2, , CI2, , NaOH, , Fuels, margarine, ammonia for fertilizers, , Water treatment, swimming pools,, PVC, disinfectants, CFCs. pesticides, , De-greasing metals, soaps, and detergents, paper, making, artificial fibres, , Which of the following two products are obtained from the process shown in the given, figure?, 1. HCl, 2. Bleach, 4. H 2SO 4, , 3. Litmus, , Codes, (a) 1 and 2, , (b) 1 and 3, , (c) 1 and 4, , (d) 2 and 4, , 15. Identify the compound X on the basis of the reactions given below. Also, choose the, correct chemical formulae of A, B and C., +Zn, ¾¾®, A, Compound X, , +HCI, ¾¾®, B + H 2O, +CH COOH, , 3, ¾¾¾®, C + H 2O, , X, , A, , B, , C, , (a), , NaOH, , Na 2 ZnO2, , NaCl, , CH3 COONa, , (b), , NaCl, , Na 2 ZnO2, , NaOH, , CH3 COONa, , (c), , HCl, , Na 2 ZnO2, , H2 SO4, , CH3 COONa, , (d), , CH3 COONa, , NaOH, , NaCl, , Na 2 ZnO2, , Answers, , THE QUALIFIERS, , 1. (c), 6. (d), 11. (d), , 2. (a), 7. (d), 12. (d), , 3. (d), 8. (b), 13. (b), , 4. (c), 9. (c), 14. (a), , 5. (c), 10. (c), 15. (c), , For Detailed Solutions, Scan the code, , 3. Metals and Non-metals, 1. Ajay took calcium oxide in an iron container. He slowly added some water to it. What, would he observe?, (a) The container becomes cold, (b) The container becomes hot, (c) Green coloured solution is formed, (d) White precipitate is formed

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21, , CBSE Sample Paper Science Class X (Term I), , 2. Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved, by inverting a test tube over it, as shown in figure below., , Gas A, , Test tube, Spatula containing sulphur powder, Burner, , Collection of gas, , Identify gas A in the given experiment., (a) SO 2, (b) SO, , (c) HS, , (d) S 8, , 3. Which of the following can undergo a chemical reaction?, (a) MgSO 4 + Fe, , (b) ZnSO 4 + Fe, , (c) MgSO 4 + Pb, , 4., , (d) CuSO 4 + Fe, , Metal, Yes, , React with, cold water, , P, , No, Yes, , React with, steam, , Q, , No, R, , Which of the following two combinations are correct?, 1. P—Sodium, Q—Aluminium, 2. P—Aluminium, Q—Zinc, 3. Q—Zinc, R—Lead, 4. Q—Copper, R—Silver, (a) 1 and 3, , (b) 2 and 4, , (c) 3 and 4, , (d) 1 and 4, , B, C and D., , Numbers of electrons, , 5. The graph given below depicts number of electrons in an atom of different elements A,, 10, 8, 6, 4, 2, 0, , A, , B, , C, , Which of the following element is a metal?, (a) A, (b) B, (c) C, , D, , (d) D, , respectively. A few pieces of iron filings were then added to both the solutions. The four, students A, B , C and D recorded their observations in the form of a table as given., Student, , Aluminium sulphate solution (I), , Copper sulphate solution (II), , A, , Colourless solution changes to light green., , Blue colour of the solution is retained., , B, , Colourless solution does not change., , Blue colour of the solution changes to green., , C, , Colourless solution changes to light blue., , Blue colour of the solution changes to green., , D, , Colourless solution remains unchanged., , Blue colour of the solution fades away., , THE QUALIFIERS, , 6. Aluminium sulphate and copper sulphate solutions were taken in two test tubes I and II,

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22, , CBSE Sample Paper Science Class X (Term I), , Which of the above represents the correct set of observations that would be recorded, by the student?, (a) A, (b) B, (c) C, (d) D, , 7. The composition of aqua-regia is, (a) Dil.HCl : Conc. HNO3, 3:1, (c) Conc. HCl : Conc. HNO3, 3:1, , (b) Conc. HCl : Dil. HNO3, 3:1, (d) Dil. HCl : Dil. HNO3, 3:1, , 8. A more reactive metal displaces a less reactive metal from the aqueous solution of the, latter. From the following sets tell which one represents a correct picture of both the, possible (✓) and impossible (✘) reactions between metals and the solutions of different, salts?, Metal, , Al2 (SO4 )3, , CuSO4, , FeSO4, , ZnSO4, , (a) Al, , ✘, , ✓, , ✓, , ✓, , (b) Cu, , ✓, , ✘, , ✘, , ✘, , (c) Fe, , ✓, , ✓, , ✘, , ✘, , (d) Zn, , ✘, , ✓, , ✘, , ✓, , 9. A student performed the following four experiments,, CuSO4 (aq), , I, , Cu, , Fe, , Zn, , Al, , CuSO4 (aq), , CuSO4 (aq), , CuSO4 (aq), , IV, , III, , II, , In which experiment(s) would he find the formation of a solid deposition?, Codes, (a) I, II and IV, (b) I and II, (c) I, II and III, (d) II, III and IV, , 10. A student takes four test tubes containing solutions of different colours marked I, II, III, and IV as shown below., The table given below gives information about four solution I, II, III and IV., , THE QUALIFIERS, , Solutions, I, , Colour of solutions, Colourless, , II, , Blue, , III, , Orange, , IV, , Pale green, , Which test tubes could be containing copper sulphate solution and ferrous sulphate, solution?, Codes, (a) I and II, respectively, (c) I and III, respectively, , (b) II and IV, respectively, (d) III and IV, respectively

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23, , CBSE Sample Paper Science Class X (Term I), , 11. An electrician want to use a piece of element to complete a broken electric circuit. He, has elements W, X, Y and Z as follows, Properties, , Elements, Insulator, , Melting point, , Ductility, , W, , P, , Low, , O, , X, , O, , High, , P, , Y, , P, , Low, , P, , Z, , O, , High, , O, , Which of the above element is useful for the electrician?, (a) W and Z, (b) X only, (c) Y only, , 12., , (d) Z and X, , Elements, X, , Y, , Z, , Mercury, , Boron, , Carbon, , Identify the correct option from the given table which represent the type of elements, according to their respective examples., X, , Y, , Z, , (a), , Metal, , Non-metal, , Metalloids, , (b), , Non-metal, , Metal, , Metalloids, , (c), , Metal, , Metalloids, , Non-metal, , (d), , Non-metal, , Metalloids, , Non-metal, , 13. Which of the following element form amphoteric oxides?, (a) Cu, , (b) Al, , (c) K, , (d) Fe, , 14. Which of the following statement is correct?, 1. Aqua regia is a highly corrosive, fuming liquid., 2. Non-metals are non-malleable but are ductile., 3. NaCl is an ionic compound., 4. Metalloids show properties of both metals and non-metals., Codes, (a) 1, 2, 4, , (b) 1, 3, 4, , (c) 2, 3, 4, , (d) 1 and 3, , 15. The electronic configuration of A, B and C are, , (d) A and C, , Answers, 1. (b), 6. (b), 11. (b), , 2. (a), 7. (c), 12. (a), , 3. (d), 8. (a), 13. (b), , 4. (a), 9. (c), 14. (b), , 5. (a), 10. (b), 15. (b), , For Detailed Solutions, Scan the code, , THE QUALIFIERS, , A : 2, 8, B : 2, 8, 7, C : 2, 8, 1, Which of the given element is a non-metal?, (a) A, (b) B, (c) C

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24, , CBSE Sample Paper Science Class X (Term I), , 4. Life Processes, Direction (Q. Nos. 1-30) Each of the question has four options out of which only one is correct., Select the correct option as your answer., , 1. Carefully study the diagram of the cross-section of leaf with lables (i) to (iv). Select the, correct option which gives correct identification and main function and/or characteristics., Waxy, cuticle, (i), (ii), Air spaces, (iii), (iv), Stomatal pore, , (a) (i)-Upper epidermis – It contains large number of stomata., (b) (ii)-Chloroplast – Site for photosynthesis, (c) (iii)-Guard cell – Protective layer of cells, (d) (iv)-Lower epidermis – It has no stomata, , 2. Identify the option that indicates the correct information about labels (i) and (ii)., (i), , (ii), , (a) (i)—Systematic circulation, (ii)—Pulmonary circulation, (b) (i)—Systematic circulation, (ii)—Systematic circulation, (c) (i)—Pulmonary circulation, (ii)—Systematic circulation, (d) (i)—Double circulation, (ii)—Single circulation, , 3. Which of the following option perform same functions?, , THE QUALIFIERS, , (a) Stomata and veins, (c) Lenticels and xylem, , (b) Stomata and lenticels, (d) Sieve tube and stomata, , 4. Which of the following is an example of excretion?, (a) Release of insulin from the pancreas, (c) Removal of carbon dioxide from the lungs, , (b) Release of saliva from the salivary glands, (d) Removal of faces from the alimentary canal, , 5. In which order do these events occur in human nutrition?, (a) Digestion ® Ingestion ® Absorption ® Assimilation, (b) Digestion ® Ingestion ® Assimilation ® Absorption, (c) Ingestion ® Digestion ® Absorption ® Assimilation, (d) Ingestion ® Digestion ® Assimilation ® Absorption

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25, , CBSE Sample Paper Science Class X (Term I), , 6. The blood returning to the heart from lungs via pulmonary veins has more, (a) RBC per mL of blood, (b) haemoglobin per mL of blood, (c) oxygen per mL of blood, (d) nutrients per mL of blood, , 7. Observe the diagram of human respiratory system., A, , Nasal, passage, Trachea, (windpipe), , Pharynx, Larynx, Bronchi, , B, , D, Respiratory, bronchioles, , Bronchioles, , C, , Match the labelling referred in Column I and correlate it with the Column II., Column I, , Column II, , A, , 1., , They helps in the expansion and contraction of thoracic cavity., , B, , 2., , They are the structural and functional unit of lungs., , C, , 3., , It is part through which air is taken in., , D, , 4., , It always contain a residual volume., , Codes, A, (a) 3, (c) 3, , B, 4, 2, , C, 2, 1, , D, 1, 4, , A, (b) 3, (d) 3, , B, 1, 4, , C, 4, 1, , D, 2, 2, , 8. Identify the option that indicates the correct order of organ involve in urine formation,, storage and passing out of urine., Left renal artery, Left renal vein, , Aorta, , (i), , Inferior vena, cava, , (a) (i) Kidney, (ii) Ureter, (iii) Urethra, (b) (i) Kidney, (ii) Urinary bladder, (iii) Urethra, (c) (i) Kidney, (ii) Urethra, (iii) Ureter, (d) (i) Kidney, (ii) Urinary bladder, (iii) Ureter, , (ii), , THE QUALIFIERS, , (iii)

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26, , CBSE Sample Paper Science Class X (Term I), , 9. Taking their number into account, select the correct pair., (a) Ureter and urinary bladder, (b) Kidney and urinary bladder, (c) Urethra and urinary bladder, (d) Urethra and kidney, , 10. Find out the incorrect statement given below., (a) Length of small intestine in various animals depend upon the type of food they eat, (b) Enzymes for digestion of carbohydrates are not secreted in gastric juice, (c) In an organism, different enzymes have different pH, (d) Absorption of nutrients mostly occur in large intestine, , 11. Identify the option that indicates the correct blood vessels connected at location (i), (ii),, (iii) and (iv)., (i), (ii), (iii), , (iv), , (a) (i) Vena cava , (ii) Aorta, (iii) Pulmonary artery, (iv) Pulmonary vein, (b) (i) Vena cava, (ii) Pulmonary vein, (iii) Pulmonary artery, (iv) Aorta, (c) (i) Vena cava, (ii) Pulmonary artery, (iii) Pulmonary vein, (iv) Aorta, (d) (i) Vena cava, (ii) Aorta, (iii) Pulmonary vein, (iv) Pulmonary artery, , 12. The liquid which collects in the cavity of Bowman’s capsule is, (a) concentrated urine, (c) glycogen and water, , (b) blood plasma minus proteins, (d) used bile for excretion, , 13. The deoxygenated blood from the body first enters, (a) into right atrium through vena cava, (b) into left atrium through vena cava, (c) into right ventricle through vena cava, (d) into left ventricle through vena cava, , THE QUALIFIERS, , 14. In a person, the Bowman’s capsule of the nephron is not functioning at all. What will, its effect be on urine formation?, (a) The urine will not be formed, (b) The blood will not be filtered properly, (c) Quantity and quality of urine will be unaffected, (d) No effect will be seen, , 15. What happens to the inhaled air as it passes through the nasal cavity?, (a) Warmed to the body temperature, (b) Moistened by mucus, (c) Filtered in the nasal cavity, (d) All of the above

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27, , CBSE Sample Paper Science Class X (Term I), , 16. Observe the diagram of nephron given below., A, , Glomerulus, , B, , C, , From another, nephron, , D, , Structure of a nephron, , Match the labelling referred in Column I and correlate with the function in Column II., Column I, , Column II, , A, , 1. It carries the filtered blood away from the kidney., , B, , 2. It is involve in filtration of blood., , C, , 3. It collects the urine., , D, , 4. Involved in the selectively reabsorption of the substances., , Codes, A, (a) 2, (c) 2, , B, 4, 4, , C, 1, 3, , D, 3, 1, , A, (b) 4, (d) 2, , B, 2, 3, , C, 1, 4, , D, 3, 1, , 17. The figure given below shows a human respiratory system with labels (i) to (iv)., Identify the correct label with its function and/or characteristics., (i), (ii), , (iii), (iv), , 18. Trypsin differs from pepsin in digestion of protein in, (a) acidic medium, (b) alkaline medium, (c) neutral medium, (d) different pH range, , THE QUALIFIERS, , (a) (i) Nasal passage ® Have presence of half rings to ensure that passage does not collapse, (b) (ii) Pharynx ® It is a common passage for air and food, (c) (iii) Bronchi ® These are smaller tubes that leads to the alveoli, (d) (iv) Diaphragm ® It is the site for gaseous exchange

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28, , CBSE Sample Paper Science Class X (Term I), , 19. What will happen, if mucus is not secreted by the gastric glands?, (a) Action of enzyme pepsin will be reduced, (b) Acidic medium will not be created, (c) It will lead to the corrosion of stomach wall due to HCl, (d) The breakdown of protein will not occur, , 20. In case of kidney failure, an artificial kidney can be used. Which one of the following is, not correct for it?, (a) It is used to remove nitrogenous waste products from the blood, (b) It is different from normal kidney because there is no reabsorption involved, (c) The dialysing fluid has the same osmotic pressure blood, (d) The dialysing fluid contain some amount of nitrogenous waste, , 21. Identify the option that indicates the correct substrate for enzyme that is secreted in, location (i), (ii) and (iii)., , (i ), , (ii), , (iii), , (a) i—Starch, ii—Proteins, iii—Lipids, (c) i—Starch, ii—Lipids, iii—Starch, , (b) i—Proteins, ii—Proteins, iii—Lipids, (d) i—Starch, ii—Lipids, iii—Proteins, , 22. Excretion primarily involves, (a) removal of excess heater, (b) removal of all byproducts during catabolism, (c) removal of byproducts during anabolism, (d) removal of nitrogenous wastes, , THE QUALIFIERS, , 23. The secretion released into the small intestine are, (a) bile and pancreatic juices, (b) pancreatic juices, bile and intestinal juices, (c) pancreatic juices and intestinal juices, (d) intestinal juices only, , 24. Which of the following is not the function of hydrochloric acid?, (a) Creating acidic medium in stomach, (b) Digestion of proteins, (c) Facilitate the function of pepsin, (d) Killing of microbes present

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29, , CBSE Sample Paper Science Class X (Term I), , 25. The figure shown below shows a schematic plan of blood circulation in humans with, labels (i) to (iv). Identify the correct label with its functions., (i), (ii), , (iv), , (iii), , (a) (i) Capillaries of body organs ® Exchange of gases and substances take place and, deoxygenated blood is then carried to lungs, (b) (ii) Pulmonary artery ® Carry oxygenated blood to the lungs, (c) (iii) Capillaries of lungs ® Exchange of gases takes place and oxygenated blood is, carried back to heart via pulmonary vein, (d) (iv) Pulmonary vein ® carry oxygenated blood to the body parts, , 26. The rate of breathing is much faster in aquatic organisms than those of terrestrial, organisms because, (a) the availability of oxygen is fairly high in water, (b) the gills are better developed respiratory organs than lungs, (c) the availability of oxygen is fairly low in water, (d) they take in water through mouth, , 27. The wall of the ventricle are much thicker than of atrium because, (a) it has to pump the blood to distant location, (b) it always receive oxygenated blood, (c) it is present below the atrium, (d) it has to store the blood, , 28. The figure given below shows human digestive system with labels (i) to (iv). Identify, the correct labels with its function and/or characteristics., , (iii), (i ), , (ii), , THE QUALIFIERS, , (iv)

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30, , CBSE Sample Paper Science Class X (Term I), , (a) (i) Liver—It stores bile, (b) (ii) Small intestine—Maximum absorption of water occurs, (c) (iii) Stomach—Digestion of proteins begins here, (d) (iv) Large intestine—Absorption of digested food takes place, , 29. Identify the phase of digestion which is represented in the diagram of nutrition in, Amoeba. Arrow indicates the flow of stages of nutrition process., Nucleus, (a), , (b), , Pseudopodia, Food particle, Food vacuole, Food particle, , (c), , (d), , Undigested food, removed, , Nutrition in Amoeba, , (a) The pseudopodia forms the food vacuole for the egestion of undigested food, (b) The pseudopodia fuses over the food particle forming a food vacuole for the absorption, of the food, (c) The pseudopodia forms the food vacuole for the excretion, (d) The pseudopodia fuses over the nucleus forming a food vacuole for the absorption of food, , 30. Which of the following will not occur, if the guard cells stop working ?, (a) Regulation of transpiration, (c) Conduction of water, , (b) Conduction of food, (d) Decolouration of leaves, , Answers, , THE QUALIFIERS, , 1. (b), 6. (c), 11. (b), 16. (a), 21. (a), 26. (c), , 2. (c), 7. (d), 12. (b), 17. (b), 22. (d), 27. (a), , 3. (b), 8. (b), 13. (a), 18. (b), 23. (b), 28. (c), , 4. (c), 9. (c), 14. (b), 19. (c), 24. (b), 29. (b), , 5. (c), 10. (d), 15. (d), 20. (d), 25. (c), 30. (c), , For Detailed Solutions, Scan the code, , 5. Light : Reflection and Refraction, 1. The velocity of light in glass is 2 ´ 10 8 m/s and that in air is 3 ´ 10 8 m/s. By how much, would an ink dot appear to be raised, when covered by a glass plate 6.0 cm thick?, (a) 2.0 cm, (b) 4.0 cm, (c) 6.0 cm, (d) 1.5 cm, , 2. A point object is placed at the centre of a glass sphere of radius 6 cm and refractive, index 1.5. The distance of the virtual image from the surface of the sphere is, (a) 2 cm, (b) 4 cm, (c) 6 cm, (d) 12 cm

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31, , CBSE Sample Paper Science Class X (Term I), , 3., q1, n1, n2, q2, , Which of the following is not the correct representation of Snell’s law?, n, sin q 2, (a) n1 sin q 1 = n2 sin q 2, (b) 1 =, n2 sin q 1, n2 sin q 1, (d) n1 sin q 2 = n2 sin q 1, (c), =, n1 sin q 2, , 4. If a symmetrical convex lens of focal length f is cut as shown, f, , f¢, , New focal length of lens is f ¢, which of the following is correct?, 1, (c) f = f ¢, (a) f > f ¢, (b) f =, f¢, , (d) f ¢ = 2 f, , 5. Which of the following factors determine the focal length of a lens?, (a) Radii of curvature of the surface of the lens, (b) Nature of material of the lens, (c) Nature of medium in which lens is placed, (d) All of the above, , 6. An object is held at a distance of 60 cm from a convex mirror of focal length 20 cm. At, what distance from the convex mirror, should a plane mirror be held so that image in, the two mirrors coincide?, , O, , F, , C, , 60 cm, , (a) 37.5 cm, (c) 15 cm, n2, , n1, , A concave lens made of a material of refractive index n1 is kept in a medium of, refractive index n2 . A parallel beam of light is incident on the lens as shown. Complete, the path of rays of light emerging from the concave lens if n1 < n2 ., , THE QUALIFIERS, , 7., , (b) 22.5 cm, (d) 75 cm

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32, , CBSE Sample Paper Science Class X (Term I), , n2, , n1, , n1, , n2, , (a), , n2, , n1, , n1, , n2, , (c), , (b), , (d), , 8. Study the given ray diagrams and select the correct statement from the following., X, , X, , Screen, Screen, 25 cm, , 20 cm, , (a) Device X is a concave mirror and device Y is a convex lens, whose focal lengths are 20, cm and 25 cm respectively., (b) Device X is a convex lens and device Y is a concave mirror, whose focal lengths are 10 cm, and 12.5 cm respectively., (c) Device X is a concave lens and device Y is a convex mirror, whose focal lengths are 20 cm, and 25 cm respectively., (d) Device X is a convex lens and device Y is a concave mirror, whose focal lengths are 20 cm, and 25 cm respectively., , 9. A student, while doing the experiment on tracing the path of a ray of light passing, , through a rectangular glass slab, measured the three angles marked as q 1 , q 2 and q 3, as shown., q1, q2, , THE QUALIFIERS, , q3, , His measurements could be correct if he were to find, (a) q 1 < q 2 < q 3, (b) q 1 < q 2 but q 1 = q 3, (c) q 1 > q 2 > q 3, (d) q 1 > q 2 but q 2 = q 3, , 10. For same angle of incidence, lateral displacement of a ray on passing through a glass, slab is, (a) inversely proportional to thickness of glass slab, (b) directly proportional to thickness of glass slab, (c) not depend upon thickness of glass slab, (d) directly proportional to square of thickness of glass slab.

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33, , CBSE Sample Paper Science Class X (Term I), , 11. A tank of water when viewed normally appears to be 1 m deep. Calculate its actual, 4, depth if refractive index of water is ., 3, 4, (a) m, 3, 5, (c) m, 3, , 3, m, 4, 3, (d) m, 5, (b), , 12. A convex lens of power 3 D is held in contact with a concave lens of power -1 D., A parallel beam of light is made to fall on the combination. At what distance from the, combination will the beam get focused?, , (a) 2 cm, (c) 0.5 cm, , (b) 25 cm, (d) 50 cm, , 13. The refractive index of diamond is 2.47 and that of glass is 1.51. How much faster does, light travel in glass than in diamond?, (a) 1.51 times, (c) 2.47 times, , (b) 1.635 times, (d) 1.845 times, , 14. A child runs towards a plane mirror with a velocity of 2 m/s. With what speed will her, image move towards her?, (a) 2 m/s, (c) 4 m/s, , (b) zero, (d) 6 m/s, , 15. Which statement best describes the property of light waves illustrated in the diagram, below?, , (a) Some materials absorb light waves., (b) Some materials are refracted by some materials., (c) Light waves are refracted by some materials., (d) Light waves are emitted by some materials., , Answers, 2. (c), 7. (b), 12. (d), , 3. (d), 8. (d), 13. (b), , 4. (c), 9. (b), 14. (c), , 5. (d), 10. (b), 15. (c), , For Detailed Solutions, Scan the code, , THE QUALIFIERS, , 1. (a), 6. (b), 11. (a)

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34, , CBSE Sample Paper Science Class X (Term I), , 6. The Human Eye and the Colourful World, 1. A beam of white light is incident from glass to air on glass-air interface such that green, light just suffers TIR. The colours of the light which will come out to air are, (a) Yellow, orange, red, (b) Violet, indigo, blue, (c) All colours, (d) All colours except green, , 2. A prism ABC (with BC as base) is placed in different orientations. A narrow beam of, white light is incident on the prism as shown in figure., A, , C, , C, , C, , B, A, , C, , B, (i), , A, (ii), , A, (iii), , B, , B, , (iv), , In which of the following diagrams, after dispersion, the first colour from the top of the, spectrum corresponds to the colour of the Blood?, (a) (i), (b) (ii), (c) (iii), (d) (iv), , 3. Which of the following is the correct plot between the angle of deviation (d) and angle, of incidence (i) for a triangular prism?, d, , d, , d, , (a), , i, , (b), , i, , d, , (c), , i, , (d), , i, , 4. When the prism in dispersion experiment is rotated slowly, then it is observed that, I. white light comes out of the prism on a nearby screen., II. a band of seven colours is observed on a nearby screen with red and indigo colours, at the two ends., III. a band of seven colours is observed on a nearby screen with yellow and violet, colours at the two ends., IV. a band of seven colours is observed on a nearby screen with red and violet colours, at the two ends., Select the incorrect observations, (a) I and II, (b) II and III, (c) I, II and III, (d) I, III and IV, , THE QUALIFIERS, , 5. Which of the following is correct?, (a) l blue > l yellow > l green, , (b) l yellow > l green > l blue, , (c) l yellow > l blue > l green, , (d) l green > l blue > l yellow, , 6. At noon the sun appears white as, (a) light is least scattered, (b) all the colours of the white light are scattered away, (c) blue colour is scattered the most, (d) red colour is scattered the most

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35, , CBSE Sample Paper Science Class X (Term I), , 7. The image shows a light ray incident on a glass prism, B, A, F, , C, D, , E, , The various angles are labelled in the image. Which angle shows the angle of incidence, and angle of refraction respectively?, (a) D and A, (b) F and C, (c) B and D, (d) A and D, , 8. Why do stars appear to twinkle at night?, (a) Because the light of stars travels in different media, (b) Because the distance of star varies when earth rotates, (c) Because the star changes its position, relative to earth, (d) Because the atmosphere reflects the light at different angles., , 9. Match Column I with Column II., Column I, , Column II, , A, , Blue sky, , p., , Group of colours, , B, , Rainbow, , q., , Changing atmosphere, , C, , Spectrum, , r., , Scattering, , D, , Delayed sunset, , s., , Suspended water droplets, , A, (a) r, (c) r, , B, p, s, , C, s, p, , D, q, q, , A, (b) q, (d) s, , B, r, p, , C, p, q, , D, s, r, , 10. A ray of light is inclined to one face of a prism at an angle of 50° as shown., 42°, , 50°, , If the angle of prism is 60°, find the angle which the emergent ray makes with the, second face of the prism., (a) 28°, (b) 52°, (c) 48°, (d) 62°, X, White light, Y, Z, , Examine the above diagram and choose the correct one., (a) X is violet, Y is white light and Z is red, (b) Y is red, X is violet and Z is white light, (c) Y is violet, X is red and Z is yellow light, (d) X is red, Y is violet and Z is white light, , THE QUALIFIERS, , 11.

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36, , CBSE Sample Paper Science Class X (Term I), , 12. A student wants to know about scattering of light, so he noted down his observations, I. The path of light becomes visible due to scattering of light., II. Tyndall effect occurs in colloidal solution, III. Earth’s atmosphere is a homogeneous mixture of minute particles., IV. Size of colloidal particles is relatively larger than true solution molecules., Which one of the following is incorrect about Tyndall effect?, (a) I and III, (b) III, (c) II and IV, (d) I and IV, , 13. What is the difference in time of actual sunrise and advanced sunrise?, (a) 4 minutes, (c) 2 minutes, , (b) 3 minutes 56 seconds, (d) 1 minute, , 14. Select the incorrect statements about rainbow, I. Rainbow is caused by scattering of sunlight by tiny water droplets, present in the, atmosphere., II. A rainbow is always formed in a direction opposite to that of the sun., III. The water droplets refract and scatter the incident sunlight, then reflect it, internally, and finally refract it again when it comes out of the raindrop., IV. Different colours reach the observer’s eye due to the scattering of light and internal, reflection., (a) Both (I) and (II), (b) Both (II) and (III), (c) (I), (III) and (IV), (d) (II), (III) and (IV), , 15. The velocity of waves of all colours is same in, (a) water, , (b) oxygen, , (c) vacuum, , (d) glass, , Answers, , THE QUALIFIERS, , 1. (a), 6. (a), 11. (b), , 2. (a), 7. (d), 12. (b), , 3. (c), 8. (a), 13. (c), , 4. (c), 9. (c), 14. (c), , 5. (b), 10. (a), 15. (c), , For Detailed Solutions, Scan the code

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37, , CBSE Sample Paper Science Class X (Term I), , CBSE, QUESTION BANK, Case Study Based Questions, 1. Read the following and answer any, , (iii) Gas A, obtained above is a reactant for a, very important biochemical process, which occurs in the presence of sunlight., Identify the name of the process., , four questions from (i) to (v)., Marble's popularity began in ancient Rome, and Greece, where white and off-white, marble were used to construct a variety of, structures, from hand-held sculptures to, massive pillars and buildings., , (a) Respiration, (c) Transpiration, , (b) Photosynthesis, (d) Photolysis, , (iv) Marble statues are corroded or stained, when they repeatedly come into contact, with polluted rain water. Identify the, main reason., , (i) The substance not likely to contain, CaCO 3 is, (a) dolomite, (c) calcined gypsum, , (b) a marble statue, (d) sea shells, (a) Decomposition of calcium carbonate to, calcium oxide, (b) Polluted water is basic in nature, hence, it reacts with calcium carbonate, (c) Polluted water is acidic in nature, hence, it reacts with calcium carbonate, (d) Calcium carbonate dissolves in water to, give calcium hydroxide., , (ii) A student added 10 g of calcium, carbonate in a rigid container, secured it, tightly and started to heat it. After some, time, an increase in pressure was, observed, the pressure reading was then, noted at intervals of 5 min and plotted, against time, in a graph as shown below., During which time interval did maximum, decomposition took place?, , Pressure (atm), , 1.00, , (a) Sodium, (b) Sodium oxide, (c) Calcium, (d) Calcium oxide, , 0.75, , Sol., , 0.50, 0.25, , (a) 15-20 min, (c) 5-10 min, , (b) 10-15 min, (d) 0-5 min, , (i) (c) The substance not likely to contain CaCO 3 is, calcined gypsum. The composition of gypsum is, CaSO 4 × 2H2O. It does not have CaCO 3 . Marble is, composed of recrystallised carbonate minerals, most, commonly calcite (CaCO 3 ) or dolomite (CaMg(CO 3 )2 ), Hence, option (c) is correct., , CBSE QUESTION BANK, , (v) Calcium oxide can be reduced to, calcium, by heating with sodium metal., Which compound would act as an, oxidising agent in the above process?, , 1.25

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38, , CBSE Sample Paper Science Class X (Term I), , (ii) (d) The pressure reading was noted at intervals of, 5 min and plotted against time of the reaction which, involved:, , (b) MnO 2 is getting oxidised whereas HCl is, getting reduced., (c) MnO 2 and HCl both are getting reduced., (d) MnO 2 and HCl both are getting oxidised., , D, , CaCO 3 ¾® CaO + CO 2 ­, formation of CO2 gas increases pressure and is, maximum in (0-5) min graph as shown sharp curve in, (0-5) min., Hence, option (d) is correct., (iii) (b) Gas A (CO2), for a very important biochemical, process which occurs in the presence of sunlight, the, name of the process is photosynthesis., The reactants for photosynthesis are light energy,, water, carbon dioxide and chlorophyll, while the, products are glucose, oxygen and water., (iv) (c) Marble statues are corroded or stained when they, repeatedly come into contact with polluted rain water., Polluted rain water is acidic in nature. Hence, it reacts, with calcium carbonate., CaCO 3(s) + H 2SO 4 (aq) ¾® CaSO 4 (s) + CO 2(g) + H2O, Hence, option (c) is correct., (v). (d) Calcium oxide can be reduced to calcium by, heating with sodium metal and calcium oxide acts as, an oxidising agent because it oxidises other, substance, i.e. sodium and its gets reduced., , 2. Read the following and answer any, four questions from (i) to (v)., The reaction between MnO2 with HCl is, depicted in the following diagram. It was, observed that a gas with bleaching, abilities was released ., HCl (aq), , MnO2(s), Reactants, , Products, , CBSE QUESTION BANK, , (i) The chemical reaction between MnO 2, and HCl is an example of, (a) displacement reaction, (b) combination reaction, (c) redox reaction, (d) decomposition reaction, , (ii) Chlorine gas reacts with…… to form, bleaching powder., (a) dry Ca(OH)2, (b) dil. solution of Ca(OH)2, (c) conc. solution of Ca(OH)2, (d) dry CaO, , (iii) Identify the correct statement from the, following ;, (a) MnO 2 is getting reduced whereas HCl, is getting oxidised., , (iv) In the above discussed reaction, what is the, nature of MnO2?, (a) Acidic oxide, (b) Basic oxide, (c) Neutral oxide, (d) Amphoteric oxide, , (v) What will happen, if we take dry HCl gas, instead of aqueous solution of HCl?, (a) Reaction will occur faster, (b) Reaction will not occur, (c) Reaction rate will be slow, (d) Reaction rate will remain the same, Sol., (i) (c) The chemical reaction between MnO 2 and HCl is, redox reaction., Oxidation, (Gain of O-atoms), , MnO2 + 4HCl, , MnCl2 + 2H2O + Cl2, , Reduction, (Loss of O-atoms), , Hence, option (c) is correct., (ii) (a) Chlorine gas reacts with dry Ca(OH)2 to form, bleaching powder., Ca(OH)2 + Cl 2 ¾® Ca(OCl)2 + H2O, (Bleaching power), , Hence, option (a) is correct., (iii) (a) MnO 2 + 4HCl ¾® MnCl 2 + 2H2O + Cl 2 ­, In this reaction, MnO 2 is getting reduced to MnCl 2 by, losing oxygen atoms, while HCl is getting oxidised to, H2O by gaining oxygen atom., Hence, option (a) is correct., (iv) (b) The nature of MnO 2 is basic oxide., MnO 2 has the lowest state of oxidation., Hence, option (b) is correct., (v) (b) If we take dry HCl gas instead of aqueous, solution of HCl, then no reaction takes place., MnO 2 + HCl (dry gas) ¾® reaction will not occur., Hence, option (b) is correct., , 3. Read the following and answer any, four questions from (i) to (v)., Frothing in Yamuna :, The primary reason behind the, formation of the toxic foam is high, phosphate content in the waste water, because of detergents used in dyeing, industries, dhobi ghats and households., Yamuna’s pollution level is so bad that, parts of it have been labelled ‘dead’ as

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39, , CBSE Sample Paper Science Class X (Term I), (a) P > Q > R > S, (c) S < Q < R < P, , there is no oxygen in it for aquatic life to, survive., , (b) P > S > Q > R, (d) S < P < Q < R, , (iv) High content of phosphate ion in river, Yamuna may lead to, (a) decreased level of dissolved oxygen and, increased growth of algae., (b) decreased level of dissolved oxygen and, no effect of growth of algae., (c) increased level of dissolved oxygen and, increased growth of algae., (d) decreased level of dissolved oxygen and, decreased growth of algae., , (i) Predict the pH value of the water of river, Yamuna if the reason for froth is high, content of detergents dissolved in it., (a) 10-11, (c) 2-5, , (v) If a sample of water containing detergents is, provided to you, which of the following, methods will you adopt to neutralise it?, (a) Treating the water with baking soda, (b) Treating the water with vinegar, (c) Treating the water with caustic soda, (d) Treating the water with washing soda, , (b) 5-7, (d) 7, , (ii) Which of the following statements is, correct for the water with detergents, dissolved in it?, (a) Low concentration of hydroxide ion, ( OH- ) and high concentration of, hydronium ion ( H3O+ )., (b) High concentration of hydroxide ion, ( OH- ) and low concentration of, hydronium ion ( H3O+ )., (c) High concentration of hydroxide ion, ( OH- ) as well as hydronium ion ( H3O+ )., (d) Equal concentration of both hydroxide, ion ( OH- ) and hydronium ion ( H3O+ )., , (iii) The table provides the pH value of four, solutions P, Q, R and S., Solutions, , pH value, , P, , 2, , Q, , 9, , R, , 5, , S, , 11, , (i) (a) If high content of detergent dissolved in water of, river Yamuna then the value of pH of water will be, 10-11. Because nature of detergent is basic. So,, water becomes basic and pH of basic water may be, 7-14. Hence, correct option is (a)., (ii) (b) Almost all detergents have NaOH which is basic, in nature and gives OH - ion in water. When they, dissolved in water then the concentration of, hydroxide ion (OH- ) increases and the concentration, of hydronium ion (H3O + ) decreases., (iii) (c) The value of pH of solution depends on, hydronium ion concentration. Lower the value of pH it, means higher the hydronium ion concentration., Hence, according to given pH values the increasing, order of hydronium ion concentration will be S < Q <, R < P. (11 < 9 < 5 < 2)., (iv) (a) Phosphorus is an essential element for plant life, but when there is too much of it in water, it can speed, up eutrophication (a reduction in dissolved oxygen in, water bodies caused by an increase of mineral and, organic nutrients) of river and lakes. A sign of this is, excess algae in the lake., (v) (b) Detergents are basic in nature., So, for neutralise it, acid is required. Because vinegar, is an acid, it can neutralise detergents. Hence, option, (b) is correct., , CBSE QUESTION BANK, , Which of the following correctly represents, the solutions in increasing order of their, hydronium ion concentration?, , Sol.

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40, , CBSE Sample Paper Science Class X (Term I), , Latest CBSE, , SAMPLE PAPER, Latest Sample Question Paper for Class X (Term I), Issued by CBSE on 2 Sept 2021, , Science Class 10 (Term I), Instructions, (i) This paper is divided into three Sections:, (a) Section A – Contains 24 questions. Attempt Attempt any 20 questions., (b) Section B – Contains 24 questions. Attempt Attempt any 20 questions., (c) Section C – Contains 12 questions. Attempt Attempt any 10 questions., (ii) Each questions carries 0.80 mark., (iii) There is NO negative marking., Maximum Marks : 40, Time allowed : 90 Min., , Roll No., , Section A, Section-A consists of 24 questions. Attempt any 20 questions from this section. The first attempted 20, questions would be evaluated., , Latest CBSE SAMPLE PAPER, , 1. Reema took 5 mL of lead nitrate solution in a beaker and added approximately 4 mL of, potassium iodide solution to it., What would she observe?, (a) The solution turned red, (c) White precipitate was formed, , (b) Yellow precipitate was formed, (d) The reaction mixture became hot, , 2. Identify gas A in the following experiment., Thistle funnel, , Delivery tube, , Stand, Burning of gas A, with a pop sound, , Test tube, Dilute, sulphuric, acid, Zinc granules, , Candle, Bubbles, of gas A, Soap bubble filled, with gas A, , Soap solution, , (a) Nitrogen, (c) Oxygen, , (b) Hydrogen, (d) Carbon dioxide

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41, , CBSE Sample Paper Science Class X (Term I), , 3., , METAL, Dil.HCl, , METAL, SALT, , GAS, , Which of the following two combinations are correct ?, Metal, , Gas evolved, , (i), , Copper, , Yes, , (ii), , Iron, , Yes, , (iii), , Magnesium, , No, , (iv), , Zinc, , Yes, , (a) (i) and (iii), (c) (ii) and (iii), , (b) (i) and (iv), (d) (ii) and (iv), , 4. Which of the following correctly represents a balanced chemical equation ?, (a) Fe( s) + 4H2 O ( g) ¾® Fe 3 O 4 ( s) + 4H2 ( g), (b) 3Fe( s) + 4H2 O ( g) ¾® Fe 3 O 4 ( s) + 4H2 ( g), (c) 3Fe( s) + H2 O ( g) ¾® Fe 3 O 4 ( s) + H2 ( g), (d) 3Fe( s) + 4H2 O ( g) ¾® Fe 3 O 4 ( s) + H2 ( g), , 5. The graph given below depicts a neutralisation reaction (acid + alkali ® salt + water)., The pH of a solution changes as we add excess of acid to an alkali., 14, , A, B, C, , pH, value 7, , D, 0, Volume of acid added, , 6. In the reaction of iron with copper sulphate solution,, CuSO 4 + Fe ¾® Cu + FeSO 4, Which option in the given table correctly represents the substance oxidised and the, reducing agent ?, Substance oxidised, (a), , Reducing agent, , Fe, , Fe, , (b), , Fe, , FeSO 4, , (c), , Cu, , Fe, , (d), , CuSO 4, , Fe, , Latest CBSE SAMPLE PAPER, , Which letter denotes the area of the graph where both acid and salt are present?, (b) B, (d) D, , (a) A, (c) C

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42, , CBSE Sample Paper Science Class X (Term I), , 7. The chemical reaction between copper and oxygen can be categorised as, (a) displacement reaction, (b) decomposition reaction, (c) combination reaction, (d) double displacement reaction, , 8. Which of the given option correctly represents the parent acid and base of calcium, carbonate?, Parent acid, , Parent base, , (a), , HCl, , NaOH, , (b), , H2CO 3, , Ca(OH)2, , (c), , H3 PO 3, , CaSO 4, , (d), , H2SO 4, , CaSO 4, , 9. How will you protect yourself from the heat generated while diluting a concentrated, acid ?, (a) By adding acid to water with constant stirring, (b) By adding water to acid with constant stirring, (c) By adding water to acid followed by base, (d) By adding base to acid with constant stirring, , 10. Why is it important to balance a skeletal chemical equation?, (a) To verify law of conservation of energy, (b) To verify the law of constant proportion, (c) To verify the law of conservation of mass, (d) To verify the law of conservation of momentum, , 11. Carefully study the diagram of the human respiratory system with labels (i), (ii), (iii), and (iv). Select the option which gives correct identification and main function and /or, characteristic., , Bronchus, Cut end of rib, , heart, , Latest CBSE SAMPLE PAPER, , (i ), , (ii), (iii), , Lung, (iv), , (a) (i) Trachea: It is supported by bony rings for conducting inspired air, (b) (ii) Ribs: When we breathe out, ribs are lifted, (c) (iii) Alveoli: Thin walled sac-like structures for exchange of gases, (d) (iv) Diaphragm: It is pulled up when we breathe in

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43, , CBSE Sample Paper Science Class X (Term I), , 12. Identify the option that indicates the correct enzyme that is secreted in location (i), (ii), and ( iii) ., , (i ), , (ii), (iii), , (a) (i)-Lipase, (ii)-Trypsin, (iii)-Pepsin, (b) (i)-Amylase, (ii)-Pepsin, (iii)-Trypsin, (c) (i)-Trypsin, (ii)-Amylase, (iii)-Carboxylase, (d) (i)-Permease, (ii)-Carboxylase, (iii)-Oxidase, , 13. Opening and closing of stomatal pore depends on, (a) atmospheric temperature, (b) oxygen concentration around stomata, (c) carbon dioxide concentration around stomata, (d) water content in the guard cells, , 14. The figure given below shows a schematic plan of blood circulation in humans with, labels. Identify the correct label with its functions., (iii), , (ii), , (a) (i) Pulmonary vein - takes impure blood from body parts, (b) (ii) Pulmonary artery - takes blood from lungs to heart, (c) (iii) Aorta - takes blood from heart to body parts, (d) (iv) Vena cava - takes blood from body parts to right auricle, , Latest CBSE SAMPLE PAPER, , (iv), , (i )

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44, , CBSE Sample Paper Science Class X (Term I), , 15. Identify the phase of circulation which is represented in the diagram of heart given, below. Arrows indicate contraction of the chambers shown., , (a) Blood transferred to the right ventricle and left ventricle simultaneously, (b) Blood is transferred to lungs for oxygenation and is pumped into various organs, simultaneously, (c) Blood transferred to the right auricle and left auricle simultaneously, (d) Blood is received from lungs after oxygenation and is received from various organs, of the body, , 16. Observe the diagram of human digestive system., A, , B, C, , Latest CBSE SAMPLE PAPER, , D, , Match the labelling referred in Column I and correlate with the function in Column II., Column I, , Column II, , A, , 1., , The length of this depends on food the organism eats., , B, , 2., , Initial phase of starch digestion, , C, , 3., , Increases the efficiency of lipase enzyme action., , D, , 4., , This is the site of the complete digestion of carbohydrates, proteins and fats., , Codes, A B, (a) 1 2, (b) 2 3, (c) 2 4, (d) 4 1, , C, 3, 4, 3, 2, , D, 4, 1, 1, 3

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45, , CBSE Sample Paper Science Class X (Term I), , 17. Which of the following mirror is used by a dentist to examine a small cavity in a, patient’s teeth?, (a) Convex mirror, (b) Plane mirror, (c) Concave mirror, (d) Any spherical mirror, , 18. Which diagram shows image formation of an object on a screen by a converging lens?, 2 × Focal length, , 2 × Focal length, , (b), , (a), , Object, , Object, , Screen, , Screen, Focal length, , Focal length, , (c), , (d), Object, , Object, , Screen, , Screen, , 19. Which of the following can make a parallel beam of light when light from a point, source is incident on it?, (a) Concave mirror as well as convex lens, (b) Convex mirror as well as concave lens, (c) Two plane mirrors placed at 90° to each other, (d) Concave mirror as well as concave lens, , 20. Consider these indices of refraction: glass: 1.52; air: 1.0003; water: 1.333. Based on the, , 21. If a beam of red light and a beam of violet light are incident at the same angle on the, inclined surface of a prism from air medium and produce angles of refraction r and v, respectively, which of the following is correct?, 1, (a) r = v, (b) r > v, (c) r =, (d) r < v, v, , 22., , Concave mirror, , C, , F, , P, , Latest CBSE SAMPLE PAPER, , refractive indices of three materials, arrange the speed of light through them in, decreasing order., (a) The speed of light in water > the speed of light in air > the speed of light in glass, (b) The speed of light in glass > the speed of light in water > the speed of light in air, (c) The speed of light in air > the speed of light in water > the speed of light in glass, (d) The speed of light in glass > the speed of light in air > the speed of light in water

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46, , CBSE Sample Paper Science Class X (Term I), , Examine the above figure and state which of the following option is correct?, [one small box in the figure is equal to 1 cm], (a) The mirror has a focal length of - 6 cm and will produce an image of magnification + 1., (b) The mirror has a focal length of - 3 cm and will produce an image of magnification - 1., (c) The mirror has a focal length of - 3 cm and will produce an image of magnification + 1., (d) The mirror has a focal length of - 6 cm and will produce an image of magnification - 1., Q, , 23., , Air, P, Air, , Glass, , O, , The angle of incidence from air to glass at the point O on the hemispherical glass slab is, (a) 45°, (b) 0°, (c) 90°, (d) 180°, , 24. A prism ABC (with BC as base) is placed in different orientations. A narrow beam of white, light is incident on the prism as shown in below figure. In which of the following, diagrams, after dispersion, the third colour from the top of the spectrum corresponds to, the colour of the sky?, C, , A, , C, , B, , C, , A, C, , B, (i), , A, (ii), , A, (iii), , (a) (i), (c) (iii), , B, , B, , (iv), , (b) (ii), (d) (iv), , Section B, Section B consists of 24 questions (Sl. No. 25 to 48). Attempt any 20 questions from this section. The first, attempted 20 questions would be evaluated., , Latest CBSE SAMPLE PAPER, , 25., , Limestone, , Heated, Step 1, , X + CO2, + H2O, Step 2, , Slaked lime, , Identify the correct option from the given table which represents the type of reactions, occurring in step 1 and step 2., Endothermic, , Exothermic, , (a), , O, , P, , (b), , P, , O, , (c), , P, , P, , (d), , O, , O

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47, , CBSE Sample Paper Science Class X (Term I), , 26. In which year is the concentration of hydrogen ion the highest?, 6.00, , pH value, , 5.00, 4.00, 3.00, 2.00, 1.00, 0.00, 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011, Rain pH value, , (a) 2002, , (b) 2008, , (c) 2011, , (d) 2005, , 27. The diagram shows the reaction between metal and dil. acid., Mg+, dil.HCl, , A, , Zn+, dil.HCl, , Cu+, dil.HCl, B, , C, , Ca+, dil.HCl, D, , What is the reason for different behaviour of Mg in test tube B ?, (a) Mg is lighter element than dil. HCl, (b) Mg reacts with dil. HCl to produce H2 gas which helps in floating, (c) Mg reacts with dil. HCl to produce N2 gas which helps in floating, (d) Mg reacts with dil. HCl to produce CO2 gas which helps in floating, , 28. The table shown below gives information about four substances: A, B, C and D., Electrical conductivity, , Substance, , Melting point (K), , A, , Solid, , Liquid/Aqueous, , 295, , Good, , Good, , B, , 1210, , Poor, , Good, , C, , 1890, , Poor, , Good, , D, , 1160, , Poor, , Poor, , 29. Vinay observed that the stain of curry on a white shirt becomes reddish-brown when, soap is scrubbed on it, but it turns yellow again when the shirt is washed with plenty, of water. What might be the reason for his observation?, I. Soap is acidic in nature., II. Soap is basic in nature., III. Turmeric is a natural indicator which gives reddish tinge in bases., IV. Turmeric is a natural indicator which gives reddish tinge in acids., (a) I and II, (b) II and III, (c) I and IV, (d) II and IV, , Latest CBSE SAMPLE PAPER, , Identify ionic compounds from the above given substances., (a) A, B, (b) B, C, (c) A, B, D, (d) A, C, D

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48, , CBSE Sample Paper Science Class X (Term I), , 30. In which of the following setups would the bulb glow?, 6 volt battery, , Bulb, , 6 volt battery, , Bulb, Switch, , Switch, , Beaker, I., , Beaker, , II., , Nail, , Nail, , Dilute HCl solution, , Sugar solution, , Rubber cork, , 6 volt battery, , Rubber cork, , 6 volt battery, , Bulb, , Bulb, , Switch, , Switch, , Beaker, , Beaker, III., , IV., Nail, , Nail, , Alcohol in water, , Lime water, , Rubber cork, , (a) I and II, (c) II, III and IV, , Rubber cork, , (b) I and IV, (d) I, II and IV, , Direction (Q. No. 31 to 34) Consist of two statements – Assertion and Reason. Answer these questions, selecting the appropriate option given below :, (a) Both A and R are true and R is the correct explanation of A., (b) Both A and R are true, but R is not the correct explanation of A., (c) A is true, but R is false., (d) A is false, but R is true., , 31. Assertion Fresh milk in which baking soda is added, takes a longer time to set as curd., , Latest CBSE SAMPLE PAPER, , Reason Baking soda decreases the pH value of fresh milk to below 6., , 32. Assertion Decomposition of vegetable matter into compost is an endothermic reaction., Reason Decomposition reaction involves breakdown of a single reactant into simpler, products., , 33. Assertion Resins and gums are stored in old xylem tissue in plants., Reason Resins and gums facilitate transport of water molecules., , 34. Assertion Sky appears blue in the day time., Reason White light is composed of seven colours.

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49, , CBSE Sample Paper Science Class X (Term I), , 35. The table given below shows the reaction of a few elements with acids and bases to, evolve hydrogen gas., Which of these elements form amphoteric oxides ?, Element, , (a) A and D, , Acid, , Base, , A, , O, , O, , B, , P, , P, , C, , P, , O, , D, , P, , P, , (b) Band D, , (c) A and C, , (d) B and C, , 36. In which of the following groups of organisms, blood flows through the heart only, once during one cycle of passage through the body?, (a) Rabbit, parrot, turtle, (b) Frog, crocodile, pigeon, (c) Whale, Labeo, penguin, (d) Shark, dog fish, sting ray, , 37. What is common between extensive, network of blood vessels around walls of alveoli and in glomerulus of nephron?, (a) Thick walled arteries richly supplied with blood, (b) Thin walled veins poorly supplied with blood, (c) Thick walled capillaries poorly supplied with blood, (d) Thin walled capillaries richly supplied with blood, , 38. Plants use completely different process for excretion as compared to animals. Which, one of the following processes is not followed by plants for excretion?, (a) They can get rid of excess water by transpiration, (b) They selectively filter toxic substances through their leaves, (c) Waste products are stored as resins and gums in old xylem, (d) They excrete waste substances into the soil around them, , 39. If the power of a lens is - 4.0 D, then it means that the lens is a, , 40. Rays from Sun converge at a point 15 cm in front of a concave mirror. Where should an, object be placed so that size of its image is equal to the size of the object?, (a) 30 cm in front of the mirror, (b) 15 cm in front of the mirror, (c) Between 15 cm and 30 cm in front of the mirror, (d) More than 30 cm in front of the mirror, , 41. In which of the following groups of, organisms, food material is broken down outside the body and then absorbed in?, (a) Mushroom, green plants, Amoeba, (b) Yeast, mushroom, bread mould, (c) Paramecium, Amoeba, Cuscuta, (d) Cuscuta, lice, tapeworm, , Latest CBSE SAMPLE PAPER, , (a) concave lens of focal length - 50 m, (b) convex lens of focal length + 50 cm, (c) concave lens of focal length - 25 cm, (d) convex lens of focal length - 25 m

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50, , CBSE Sample Paper Science Class X (Term I), , 42. In a person, the tubule part of the nephron is not functioning at all. What will be its, effect on urine formation?, (a) The urine will not be formed, (b) Quality and quantity of urine is unaffected, (c) Urine is more concentrated, (d) Urine is more diluted, , 43. If the real image of a candle flame formed by a lens is three times the size of the flame, and the distance between lens and image is 80 cm, at what distance should the candle, be placed from the lens?, 40, 80, cm, cm, (d) (a) - 80 cm, (b) - 40 cm, (c) 3, 3, , 44., Principal axis, , C, , F, Object, , While looking at the above diagram, Nalini concluded the following ?, I. The image of the object will be a virtual one., II. The reflected ray will travel along the same path as the incident ray but in opposite, direction., III. The image of the object will be inverted., IV. This is a concave mirror and hence the focal length will be negative., Which of the above statements are correct?, (a) I and II, (b) I and III, (c) II, III and IV, (d) I, II, III and IV, , 45., Medium 1, , Latest CBSE SAMPLE PAPER, , Medium 2, Medium 3, Medium 4, , 1, 2, 3, , 4, 4, , In the above diagram light is travelling through different media. It is noted by a, scientist that Ð 1 = Ð 3 = Ð4 but Ð2 < Ð1. Which of the following statement would be, correct?, (a) Medium 1 is denser than medium 3 but it’s density is equal to medium 2, (b) Medium 2 is the rarest medium, (c) Medium 3 is denser than medium 1, (d) Medium 1 and 3 are essentially the same medium, but medium 2 is denser than 1 and 3, , 46. The refractive index of flint glass is 1.65 and that for alcohol is 1.36 with respect to air., What is the refractive index of the flint glass with respect to alcohol ?, (a) 0.82, (b) 1.21, (c) 1.11, (d) 1.01

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51, , CBSE Sample Paper Science Class X (Term I), , 47., , A¢, , F2, , A, B¢, , F1 B, , O, , The above lens has a focal length of, 10 cm. The object of height 2 mm is placed at a distance of 5 cm from the pole. Find the, height of the image., (a) 4 cm, (b) 6.67 mm, (c) 4 mm, (d) 3.33 mm, , 48. A cable manufacturing unit tested few elements on the basis of their physical, properties., Properties, , W, , X, , Y, , Z, , Malleable, , Yes, , No, , No, , Yes, , Ductile, , Yes, , No, , No, , Yes, , Electrical conductivity, , Yes, , Yes, , Yes, , No, , High, , Low, , Low, , High, , Melting Point, , Which of the above elements were discarded for usage by the company?, (a) W, X, Y, (b) X, Y, Z, (c) W, X, Z, (d) W, X, Z, , Section C, , Compound, , Formula, , Mass of solid present/g, , Sodium chloride, , NaCl, , 28.0, , Magnesium chloride, , MgCl 2, , 8.0, , Magnesium sulphate, , MgSO 4, , 6.0, , Calcium sulphate, , CaSO 4, , 2.0, , Calcium carbonate, , CaCO 3, , 1.0, , Total amount of salt obtained, , 45.0, , 49. Which compound in the table reacts with acids to release carbon dioxide ?, (a) NaCl, , (b) CaSO 4, , (c) CaCO 3, , (d) MgSO 4, , Latest CBSE SAMPLE PAPER, , This Section C consists of three Cases followed by questions. There are a total of 12 questions in this, section. Attempt any 10 questions from this section., The first attempted 10 questions would be evaluated., Case I The salt pans in Marakkanam, a port town about 120 km from Chennai are the third, largest producer of salt in Tamil Nadu. Separation of salt from water is a laborious process and, the salt obtained is used as raw materials for manufacture of various sodium compounds. One, such compound is sodium hydrogen carbonate, used in baking, as an antacid and in soda acid, fire extinguishers., The table shows the mass of various compounds obtained when 1 litre of sea water is, evaporated.

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52, , CBSE Sample Paper Science Class X (Term I), , 50. How many grams of magnesium sulphate are present in 135 g of solid left by, evaporation of sea water?, (a) 6 g, (b) 12 g, , (c) 18 g, , (d) 24 g, , 51. What is the saturated solution of sodium chloride called?, (a) Brine, (c) Slaked lime, , (b) Lime water, (d) Soda water, , 52. What is the pH of the acid which is used in the formation of common salt?, (a) Between 1 to 3, (c) Between 8 to 10, , (b) Between 6 to 8, (d) Between 11 to 13, , Case II The Figure shown alongside represents an activity to prove the requirements for, photosynthesis. During this activity, two healthy potted plants were kept in the dark for 72, hours. After 72 hours, KOH is kept in the watch glass in setup X and not in setup Y., Both these setups are air tight and have been kept in light for 6 hours. Then, iodine test is, performed with one leaf from each of the two plants X and Y., , Bell jar, Watch-glass, containing, potassium, hydroxide, X, , Y, , 53. This experimental setup is used to prove essentiality of which of the following, requirements of photosynthesis?, (a) Chlorophyll, (b) Oxygen, , (c) Carbon dioxide, , (d) Sunlight, , (c) moisture, , (d) sunlight, , 54. The function of KOH is to absorb, (a) oxygen, , (b) carbon dioxide, , Latest CBSE SAMPLE PAPER, , 55. Which of the following statements shows the correct results of Iodine Test performed, on the leaf from plant X and Y respectively?, (a) Blue - black colour would be obtained on the leaf of plant X and no change in colour on, leaf of plant Y, (b) Blue - black colour would be obtained on the leaf of plant Y and no change in colour on, leaf of plant X, (c) Red colour would be obtained on the leaf of plant X and brown colour on the leaf of, plant Y, (d) Red colour would be obtained on the leaf of plant Y and brown colour on the leaf of, plant X, , 56. Which of the following steps can be followed for making the apparatus air tight?, I. Placing the plants on glass plate., II. Using a suction pump., III. Applying vaseline to seal the bottom of jar., IV. Creating vacuum., (a) I and II, (b) II and III, (c) I and III, , (d) II and IV

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53, , CBSE Sample Paper Science Class X (Term I), , Case III. Noor, a young student, was trying to demonstrate some properties of light in her, Science project work. She kept ‘X’ inside the box (as shown in the figure) and with the help of a, laser pointer made light rays pass through the holes on one side of the box. She had a small, butter-paper screen to see the spots of light being cast as they emerged., Ray 2, Ray 1, X, Ray 2, Ray 1, , 57. What could be the ‘X ’ that she placed inside the box to make the rays behave as, shown?, (a) a converging lens, (c) a plane mirror, , (b) a parallel-sided glass block, (d) a triangular prism, , 58. She measured the angles of incidence for both the rays on the left side of the box to be, 48.6°. She knew the refractive index of the material ‘X ’ inside the box was 1.5. What, will be, the approximate value of angle of refraction?, (a) 45°, (b) 40°, (c) 30°, (d) 60°, (Use the value : sin 48.6° » 0.75), , 59. Her friend noted the following observations from this demonstration :, (i) Glass is optically rarer than air., (ii) Air and glass allow light to pass through them with the same, velocity., (iii) Air is optically rarer than glass., (iv) Speed of light through a denser medium is faster than that of a rarer medium., (v) The ratio of sine of angle of incidence in the first medium to the ratio of sine of angle of, refraction in the second medium, gives the refractive index of the second medium with, respect to the first one., Which one of the combination of the above statements given below is correct?, (a) (ii), (iv) and (v) are correct, (b) (iii) and (iv) are correct, (c) (i), (iv) and (v) are correct, (d) (iii) and (v) are correct, then, (a) lateral shift of the rays would have been less, (b) lateral shift of the rays would have been more, (c) lateral shift of the rays would remain the same as before, (d) there is not enough information to comment on any of the above statements, , ANSWERS, 1. (b), 11. (c), , 2. (b), 12. (b), , 3. (d), 13. (d), , 4. (b), 14. (d), , 21. (d), 31. (c), 41. (b), , 22. (b), 32. (d), 42. (d), , 23. (b), 33. (c), 43. (d), , 24. (b), 34. (b), 44. (c), , 51. (d), , 52. (a), , 53. (c), , 54. (b), , 5. (d), 15. (b), 25. (c), , 6. (a), 16. (b), 26. (a), , 7. (c), 17. (c), 27. (b), , 8. (b), 18. (c), 28. (b), , 9. (a), 19. (a), 29. (b), , 10. (c), 20. (c), 30. (b), , 35. (b), 45. (d), 55. (b), , 36. (d), 46. (b), 56. (c), , 37. (d), 47. (c), 57. (b), , 38. (b), 48. (b), 58. (c), , 39. (c), 49. (c), 59. (d), , 40. (a), 50. (c), 60. (a), , Latest CBSE SAMPLE PAPER, , 60. If the object inside the box was made of a material with a refractive index less than 1.5

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54, , CBSE Sample Paper Science Class X (Term I), , SOLUTIONS, 1. When Reema added approximately 4 mL of, potassium iodide solution to 5 mL of lead, nitrate solution, then yellow precipitate of lead, iodide was formed along with potassium, nitrate., 2KI + Pb(NO3 )2 ¾® PbI2 + 2KNO3, Potassium, iodide, , Lead nitrate, , Lead iodide Potassium, (Yellow ppt.) nitrate, , 2. In the given experiment, the gas evolved (A) is, hydrogen as zinc reacts with dil. H2SO4 to form, zinc chloride and hydrogen gas., Zn + dil.HCl ¾® ZnCl 2 + H 2 ­, (Zinc), , (Dilute, hydrochloric acid), , (Zinc, chloride), , (Hydrogen), , The presence of hydrogen is tested by bringing, a burning candle near the soap bubbles filled, with gas A (hydrogen). On doing so, hydrogen, gas burns with pop sound due to the reaction, between hydrogen and oxygen present in the, air makes a small explosion with pop sound., 3. (i) When copper metal reacts with dilute, hydrochloric acid, then no reaction occurs, because copper cannot displace hydrogen, from HCl to evolve H 2 gas as it is less, reactive than hydrogen., (ii) When iron reacts with dilute hydrochloric, acid, then iron chloride and hydrogen gas, is formed., Fe( s) + dil. HCl( aq) ¾® FeCl 2( aq) + H 2( g ), , Latest CBSE SAMPLE PAPER, , In this reaction, Fe being more reactive,, displaces hydrogen from hydrochloric acid, to form FeCl 2 and H 2 gas., (iii) The reaction between magnesium and, dilute hydrochloric acid produces, magnesium chloride and hydrogen gas., Mg( s) + dil. HCl( aq) ¾® MgCl 2( aq) + H 2( g ), In this reaction, Mg being more reactive,, displaces hydrogen from hydrochloric acid, to form MgCl 2 and H 2 gas., (iv) When zinc is treated with dilute HCl, then, zinc chloride and hydrogen gas is, produced., Zn( s) + dil. HCl( aq) ¾® ZnCl 2( aq)+ H 2( g ), In this reaction, zinc being more reactive,, displaces hydrogen from HCl and forms, zinc chloride and hydrogen gas., Hence, the combination of (ii) and (iv) is, correct., 4. A balanced equation is an equation for a, chemical reaction in which the number of, , atoms for each element in the reaction is same, or equal for both the reactants and the products., In (a) reaction,, Fe( s) + 4H 2O( g ) ¾® Fe3O 4( s) + 4 H 2( g ), Fe-atoms are not balanced., In (b) reaction,, 3Fe( s) + 4H 2O ( g ) ¾® Fe3O 4( s) + 4 H 2( g ), Number of atoms of all elements are equal on, both the side of the reaction. Hence, it is a, balanced equation., In (c) reaction,, 3Fe( s) + H 2O ( g ) ¾® Fe3O 4( s) + 4 H 2( g ), O-atoms are unbalanced., In (d) reaction,, 3Fe( s) + 4H 2O ( g ) ¾® Fe3O 4( s) + 4 H 2( g ), H-atoms are not balanced., 5. Acid and base reacts with each other to form, salt and water, this reaction is known as, neutralisation reaction., Acid + Base ¾® Salt + H2O, As the pH of acid is below 7, so the letter, which donates the area of the graph where, both acid and salt are present after addition of, excess acid to an alkali is (D)., 6. The reaction between iron and copper sulphate, solution is as follows :, CuSO 4 + Fe ¾® Cu + FeSO 4, The substance which gets oxidised is called, reducing agent. Hence, in the given reaction,, Fe is oxidised and consequently acts as, reducing agent by gaining oxygen atoms to, form FeSO 4 ., 7. The chemical reaction between copper and, oxygen can be written as :, Cu( s) + O 2( g ) ¾® 2 CuO( s), In this reaction, two reactants, Cu and O 2, react with each other and form single product,, i.e. copper oxide, CuO. Hence, this reaction is, categorised as combination reaction., 8. The term ‘parent acid’ and ‘parent base’ are, used to describe the original compounds that, combined to make the salt., So, calcium carbonate salt can be obtained by, the reaction between H 2CO 3 (parent acid) and, Ca(OH)2 (parent base) to form calcium, carbonate salt and water., H 2CO 3 + Ca(OH)2 ¾® CaCO 3 + H 2O, Carbonic acid, (Parent acid), , Calcium hydroxide, (Parent base), , Calcium, carbonate, (Salt), , Water

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55, , CBSE Sample Paper Science Class X (Term I), , 9. The process of diluting a concentrated acid is a, highly exothermic one. Thus, while diluting a, concentrated acid, one should add acid to, water with constant stirring to avoid any, mishappening. The heat generation in the, process may cause the mixture to splash out., 10. The balancing of chemical equation is based on, the law of conservation of mass, which states, that the total mass of the system must remain, constant throughout the reaction i.e. mass of, the reactants should be equal to total mass of, the product., 11. Option (c) is the correct., (iii)-Alveoli are thin walled sac-like structures, present in lungs for gaseous exchange., (i)-Trachea is supported by ring of cartilages, which prevent it from collapsing in the, absence of air., (ii)-Ribs lift up, when we breathe in., (iv)-Diaphragm contracts and flattens, when, we breathe in., 12. (i) Salivary glands present in our mouth, secrete salivary amylase for digestion of, starch., (ii) Stomach secretes pepsin which helps in, digestion of protein., (iii) Trypsin is produced by the pancreas in an, inactive form called trypsinogen. It enters, the small intestine and is converted to, active trypsin., 13. The opening and closing of stomata is, controlled by the guard cells. When water, flows into the guard cells, they swell up and, the curved surface causes the stomata to open., When the guard cells loses water, they shrink, and become flacid, thus closing the stomata., , 15. The given diagram shows contraction of right, and left ventricles of heart. Due to contraction, of right ventricle, blood is transferred to lungs, for oxygenation through pulmonary artery., Due to contraction of left ventricle, oxygenated, blood is pumped into various organs through, aorta. Both these contractions take place, simultaneously., , (A) Intial phase of starch digestion take place, in mouth by the help of salivary glands., (B) Liver increases the efficiency of lipase, enzyme by providing alkaline medium in, small intestine., (C) Small intestine is the site of the complete, digestion of carbohydrates, proteins and fats., (D) The length of small intestine depends on, food the organism eats., 17. Concave mirrors are used by dentists to examine, a small cavity in a patient’s teeth because these, mirrors give enlarged image of the teeth., If an object is placed close to a concave mirror, it, forms an erect and enlarged image of the object., So, the dentist holds the mirror in such a way that, the tooth lies within its focus as shown below., A¢, A, F B, , C, , P, , B¢, , 18. The ray coming parallel to the principal axis, after refraction will pass through principal, focus in case of convex lens., Similarly, a ray directed to optical centre will, emerge out undeviated., Therefore, the correct image formation of an, object on a screen by a converging lens is,, Focal length, , Object, , Screen, , 19. Concave mirror as well as convex lens can make, a parallel beam of light when light from a point, source is incident on it, as shown below., , C, , P, , F, , Concave mirror, , F, , O, , F, , Convex lens, , 20. Given, m g = 1.52 , m a = 1.0003, m w = 1333, ., Speed of light in vacuum, Speed of light in medium, c, m=, vm, , As we know, m =, \, , Latest CBSE SAMPLE PAPER, , 14. (iv) Vena cava collects deoxygenated blood, from body parts and carries it to right, auricle., (i) Pulmonary vein carries oxygenated blood, from lungs to the heart., (ii) Aorta takes blood from heart to all body, parts except lungs., (iii) Pulmonary artery takes deoxygenated, blood from heart to lungs., , 16. Option (b) shows correct matches.

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56, , CBSE Sample Paper Science Class X (Term I), , c, = 1.52, vg, c, For air, m a =, = 10003, ., va, c, For water, m w =, = 1333, ., vw, , For glass, m g =, , …(i), , 24. Generally, in case of a prism (ii), the formation, of spectrum is shown below, A, , …(ii), …(iii), , Red, Orange, Yellow, Green, Indigo Blue, Violet, , From Eq. (i), (ii) and (iii), we get, \, , mg > mw > ma, c, c, c, >, >, vg vw va, , or, , va > vw > vg, , C, , Hence, speed of light in air > speed of light in, water > speed of light in glass., 21. Red light has the maximum wavelength and, violet light has the minimum wavelength., So in any medium, red light travels fastest and, deviates least, while violet light travels slowest, and deviates maximum, i.e. Wavelength µ, 1, Velocity µ, Deviation, So, the angle of refraction of red light ( r) is less, than the angle of refraction of violet light ( v ), [i.e. r < v ]., 22. On observing the given figure, we notice that, the object is placed at centre of curvature of, concave mirror., So, the image will be formed at center of, curvature and of same size as that of object but, inverted, as shown below., A, F, , B, B¢ C, , P, , B, , In the above figure, from top the third colour is, yellow. But we can see that from bottom the, third colour is blue which is the colour of sky., So we can obtain the correct situation by, inverting the prism. Thus the required, orientations can be found in case (ii)., B, , C, , A, , 25. In step 1, limestone (CaCO 3 ) is heated and, calcium oxide and carbon dioxide are formed., So, X is calcium oxide and the reaction is, endothermic because heat is given to the, reactant., In Step 2, the products formed in step 1,, which are CaO and CO2 are treated with, water, then slaked lime is produced along, with evolution of heat. So, step 2 involves, exothermic reaction., The complete reaction can be written as, Heated, , Limestone ¾¾¾®, , Latest CBSE SAMPLE PAPER, , A¢, , So, the mirror has a focal length of - 3 cm and, will produce an image of magnification - 1., 23., , Q, Air, P, Air, , Glass, , O, , Normal at any point on the curved surface of, uniform hemisphere is along the radial line of, that hemisphere because the tangent at that, point is perpendicular to the radius vector. So,, the normal at point O in given figure is line OP., As the incident ray from air travels along the, normal OP. Therefore, the angle of incidence, from air to glass at the point O on the, hemispherical glass slab is 0º., , Violet, Indigo, Blue, Green, Yellow, Orange, , (CaCO3 ), , endothermic, , CaO + CO2, Exothermic ½ + H2O, , ¯, Slaked lime + Heat, ( Ca(OH)2 ), , 26. The concentration of hydrogen ions is, inversely related to its pH value according to, the following expression :, pH = - log[H+ ], So, according to graph, the pH value touched, the lowest in 2002. Hence, the concentration of, H + ions is highest in 2002., 27. When magnesium reacts with dil.HCl in test, tube B, then there is formation of salt, i.e., MgCl 2 and hydrogen gas comes out as bubbles., This hydrogen gas bubbles are responsible for, the floating of magnesium metal., Mg + 2 HCl ¾® MgCl2 + H2 ­, (Dil.)

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57, , CBSE Sample Paper Science Class X (Term I), , 28. The ionic compounds are crystalline solids and, hard in nature. Hence, they have high melting, point and good conductor of electricity in, aqueous form. So, according to the information, given in table, B and C substances have high, melting points and good electrical conductivity, in aqueous form., So, B and C are ionic compounds., 29. Both (II) and (III) reasons are correct. Soap is, made up of a weak acid and a strong base,, therefore, it is basic in nature and in basic, medium, turmeric (natural indicator) gives, reddish tinge., 30. In (I) setup, the electrolyte is dilute HCl, solution which can produce free ions on, dissociation in water to conduct electricity. So,, the bulb will glow in this setup ., In (II) setup, the electrolyte is sugar solution, which does not conduct electricity as it does, not dissociate into free ions in water. Hence,, the bulb will not glow., In (III) setup, the electrolyte is alcohol, dissolved in water does not conduct electricity, because it is very weak acid and does not, dissociate completely into free ions. Hence, the, bulb will not glow., In (IV) setup , the electrolyte is lime water, which contains citric acid and dissociates into, free ions to conduct electricity. Hence, the bulb, will glow., 31. Assertion is true, but Reason is false because, baking soda, being a base, increase the pH, value of fresh milk to above 6., , 33. Assertion is true, but Reason is false., In plants, waste products are stored as resins, and gums in old xylem. They do not facilitate, transport of water molecules. Elements of, xylem help in conduction of water., 34. During the day time, sky appears blue. This is, because the size of the particles in the, atmosphere is smaller than the wavelength of, visible light, so they scatter the light of shorter, wavelength, i.e. blue colour. This scattered, blue light enters our eye., When a white light passes through a prism, it, splits into seven colours, i.e. VIBGYOR. This, band of seven colours is called spectrum of, white light., , 35. Amphoteric oxides are those oxides which, can act as both acid and base., So, the element B and D form amphoteric, oxides as they react with both acid and base, and evolve H 2 gas., 36. Single circulation is present in organisms with, a 2-chambered heart, which is seen in fishes, such as shark, dog fish, Labeo and sting ray., Turtle and frog have 3-chambered heart,, whereas rabbit, parrot, pigeon, whale, penguin, and crocodile have 4-chambered heart. Hence,, they do not show single circulation of blood in, heart., 37. An extensive network of thin walled capillaries, richly supplied with blood is present around, walls of alveoli and in glomerulus of nephron., 38. Plants do not have specific organ for excretion., They use different strategies for removing their, wastes such as excess water is removed by, transpiration, some wastes are stored in leaves, that fall off from plants. Many plant’s waste, products are stored in cellular vacuoles, and in, form of resins and gums. They also excrete, waste substances into the soil around them,, but do not selectively filter toxic substances, through their leaves., 39. Given,, Power of lens, P = - 4 D, We know that,, 100, P=, f (cm), 100 100, f ( cm ) =, =, P, -4, Þ, f ( cm ) = - 25, Negative focal length means concave lens., So, the lens is a concave lens of focal length, 25 cm., 40. When light rays from sun converge at a point, 15 cm from the mirror, this means 15 cm is, focal length of concave mirror because rays, coming from infinity will converge at focus of, the mirror., \, f = - 15 cm, As the size of image is equal to the size of, object, this means, or, Þ, , m= - 1, -v, m=, = -1, u, v=u, , Latest CBSE SAMPLE PAPER, , 32. Assertion is false, but Reason is true because, the decomposition of vegetable matter into, compost involves evolution of heat., Hence, it is an exothermic process., , \Both Assertion and Reason are true but, Reason is not correct explanation of Assertion.

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58, , CBSE Sample Paper Science Class X (Term I), , Therefore, object should be placed at centre of, curvature which makes an image at centre of, curvature of size., Hence, object should be 30 cm in front of the, mirror., 41. Yeast, mushroom and bread mould are, saprotrophs. They breakdown food outside the, body and absorb the simpler digested, particles., Green plants are autotrophic in nature., Paramecium, Amoeba are organisms having, holozoic mode of nutrition. Cuscuta, lice and, tapeworm are parasitic organisms., 42. The major function of kidney tubules is, reabsorption of ions and molecules such as, sodium ions, glucose, amino acid, water, etc. If, the tubule part of the nephron is not, functioning at all in a person, the person will, produce dilute urine as absorption of water, does not take place., 43. Given, m = - 3 [Q real image is formed by, convex lens], v = 80 cm, v, u, 80, Þ, -3=, u, 80, cm, Þ, u= 3, Hence, the candle should be placed at a, æ 80 ö, distance of ç - ÷ cm from the lens., è 3 ø, , \ Magnification, m =, , Latest CBSE SAMPLE PAPER, , 44. The complete diagram of image formation is, given below :, A, B¢, C, , B F, , A¢, , It is clearly observed that when object is placed, between center of curvature and focus of, concave mirror then the image formed is, beyond the centre of curvature which is real,, inverted and magnified., We know that a ray coming through centre of, curvature of a concave mirror, reflects back, along the same path after striking the mirror, surface., The focal length of concave mirror is negative, because it is measured along opposite to the, direction of incident light from pole., , 45. The diagram of path of light travelling through, different media is shown below,, 1, , Medium 1, , 2, , Medium 2, , 3, , Medium 3, , 4, 4, , Medium 4, , Given, Ð1 = Ð3 = Ð4 and Ð2 < Ð1, Angle of incidence of medium 1 and angle of, refraction of medium 3 are equal., This shows that medium 1, medium 3 are same, medium., As Ð2 < Ð1, means medium 2 is denser as, compared to medium 1 that’s why light ray, bent towards the normal of the plane., 46. Given, m glass = 165, . , m alcohol = 136, ., Refractive index of flint glass w.r.t air = m glass, Refractive index of alcohol w.r.t air = m alcohol, Now, refractive index of flint glass w.r.t, alcohol, m glass, 165, ., =, = 121, ., =, m alcohol 136, ., 47. Given,, Focal length, f = + 10 cm [convex lens], Height of object, h0 = 2 mm = 0.2 cm, Object distance, u = - 5 cm, Height of image, hi = ?, By lens formula,, 1 1 1, - =, v u f, On putting values, we get, 1, 1, 1, =, v ( - 5 ) 10, 1, 1, 1 1-2 -1, =, - =, =, v 10 5, 10, 10, Þ, , v = - 10 cm, , Now, magnification, m =, or, or, , v hi, =, u h0, , - 10, h, = i Þ hi = 0.4 cm, - 5 0.2, hi = 4 mm, , So, the height of image is 4 mm.

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59, , CBSE Sample Paper Science Class X (Term I), , 48. The elements X, Y and Z were dicarded for, usage by the company because for a cable, manufacturing, the element should be ductile,, malleable, good conductor of electricity and, should have high melting point and the, elements X, Y and Z do not have all these, properties. Hence, X , Y and Z are dicarded., 49. Metal carbonates on treating with acids,, releases carbon dioxide and water along with, corresponding metal salt., Hence, when calcium carbonates, CaCO 3 reacts, with acid like HCl, then calcium chloride,, CaCl 2, carbon dioxide and water will be formed., CaCO 3( s) + HCl ( aq) ¾® CaCl 2( aq) + H 2O( l ), + CO 2( g ), 50. Mass of magnesium sulphate present in per, gram solid = 6.0 g, Total amount of salt obtained = 45 g, So, in 135 g of solid,, 135, Mass of magnesium sulphate =, ´ 6 = 18 g, 45, 51. Brine is a high-concentration solution of salt,, sodium chloride in water or it is the saturated, solution of sodium chloride., 52. Common salt is formed from hydrochloric acid, and sodium hydroxide base., HCl + NaOH ¾® NaCl + H2O, So, the acid used is strong acid which has pH, value between 1 to 3., 53. The given experimental setup is used to prove, the essentiality of carbon dioxide (CO 2 ) for the, process of photosynthesis., 54. The function of KOH in setup X is to absorb, carbon dioxide (CO 2 ) present in the air., , Thus, due to absence of CO 2, the leaf fails to, produce starch. Therefore, does not turn, blue black in colour on treating with iodine, solution., In the leaf of plant Y, starch is synthesised due, to availability of CO 2, hence blue-black colour, would be obtained on treating with iodine, solution., 56. By placing the plants on glass plate and, applying vaseline to seal the bottom of jar, , 57. As it is a clearly shown that ray 1 and ray 2, travel parallel to each other, before and after, the refraction. This case is only possible in a, parallel-sided glass block., 58. Given, Angle of incidence, i = 48.6 º, Refraction index of box, m = 1.5, Now, using Snell’s law, we get, sin i, =m, sin r, sin 48.6, Þ, = 1.5, sin r, 0.75, or, Þ r = sin - 1(0.5 ), sin r =, 1.5, or, r = 30°, Hence, angle of refraction is 30º for refracted ray., 59. Light ray travels with different speed in, different medium. The velocity of light in a, medium depends on the refractive index of, that medium., c, mm =, vm, 1, or, mm µ, vm, More dense the medium, less the speed of light, ray or vice-versa., As compared to air, glass is optically denser, than air, hence speed of light ray in glass is less, than the speed of light ray in air., The ratio of sine of angle of incidence in the, first medium to the ratio of sine of angle of, refraction in the second medium, gives the, refractive index of the second medium w.r.t., the first one, which is also known as Snell’s, law., sin i, m, 1, m2 = 2 =, m1 sin r, Hence, III and V observations are correct., 60. If the object inside the box was made of a, material with a refractive index less than 1.5,, means the object inside the box becomes, optically rarer as compared to previous, material. Then the lateral shift of the rays, would have been less, because of less angle of, refraction., , Latest CBSE SAMPLE PAPER, , 55. Iodine solution is used to test the presence of, starch. KOH present in setup X absorbs CO 2., , makes the experimental apparatus air tight, whereas a suction pump will create vaccum by, removing air from the container.

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SAMPLE PAPER 1, SCIENCE, A Highly Simulated Practice Questions Paper, for CBSE Class X (Term I) Examination, , Instructions, (i) This paper is divided into three Sections:, (a) Section A – Contains 24 questions. Attempt any 20 questions., (b) Section B – Contains 24 questions. Attempt any 20 questions., (c) Section C – Contains 12 questions. Attempt any 10 questions., (ii) Each questions carries 0.80 mark., (iii) There is NO negative marking., Maximum Marks : 40, Time allowed : 90 Min., , Roll No., , Section A, Section-A consists of 24 questions. Attempt any 20 questions from this section. The first attempted 20, questions would be evaluated., , 1. Vishal took 3 mL of potassium sulphate solution in a beaker and added approximately, 3 mL of barium chloride solution. What would he observed?, (a) Insoluble yellow precipitate was formed (b) Insoluble white precipitate was formed, (c) Insoluble green precipitate was formed, (d) The soluble become blue, , 2. In the given experimental diagram of electrolysis of water, the gases produced are, Plastic mug, , Test tube, Water, , Graphite rod, , Rubber stopper, Cathode, , Anode, , 6V, Battery, , Switch, , Electrolysis of water, , (a) hydrogen and carbon dioxide, (c) oxygen and hydrogen, , (b) oxygen and nitrogen, (d) carbon monoxide and hydrogen

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64, , CBSE Sample Paper Science Class X (Term I), , 3. Which of the following represents correct balanced chemical equation?, (a)AlCl 3 + NH 4 OH ¾® Al(OH) 3 + NH 4 Cl, (b)AlCl 3 + 3NH 4 OH ¾® Al(OH) 3 + 3NH 4 Cl, (c) 2AlCl 3 + 3NH 4 OH ¾® 2 Al(OH) 3 + 2 NH 4 Cl, (d)3AlCl 3 + 4NH 4 OH ¾® Al(OH) 3 + NH 4 Cl, , 4. The element (X) reacts with acid and base,, + Acid, , X ¾¾¾, ¾® Y + H 2, + Base, Z + H2, Identify the correct option of element (X) with respect to reactivity with acid and base., Element ( X ), , Reactivity with acid, , Reactivity with base, , (a), , C, , O, , O, , (b), , K, , O, , P, , (c), , S, , P, , O, , (d), , Zn, , P, , P, , 5. The graph given below depicts the reaction between acid and base,, 14 B, pH, value, A, O, , Volume of acid, added, , Which of the following solution or sample is responsible for decline in pH value of graph?, (a) Caustic soda, (b) Lemon juice, (c) Baking soda, (d) Common salt, , 6. In the given reaction,, 2 PbO( s) + C( s) ¾® 2 Pb ( s) + CO2 ( g), Identify the correct option which represents the substance oxidised and the reducing agent., , SAMPLE PAPER 1, , Substance oxidised, , Reducing agent, , (a), , Pb, , PbO, , (b), , PbO, , Pb, , (c), , C, , C, , (d), , CO2, , PbO, , 7. The reaction between potassium bromide and silver nitrate is an example of, (a) combination reaction, (b) decomposition reaction, (c) double displacement reaction, (d) displacement reaction

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65, , CBSE Sample Paper Science Class X (Term I), , 8. Which of the given options correctly represents the parent acid and base of sodium, carbonate?, Parent Acid, , Parent Base, , (a) HCl, , Na 2 O, , (b) H2 CO2, , NaOH, , (c) H3 PO4, , Na 2 O, , (d) H2 CO 3, , NaOH, , 9. A substance ‘X’ turns blue litmus red. It also, (a) turns phenolphthalein colourless, (c) vanishes odour of vanilla, , (b) vanishes smell of clove oil, (d) turns methyl orange to yellow, , 10. Which of the following is an endothermic process?, (a) Condensation of water vapours, (c) Evaporation of water, , (b) Dilution of sulphuric acid, (d) Combustion of LPG, , 11. The given diagram shows a vertical section of the heart., 1, , 3, , 2, , 4, , Which of the following function of the numbered blood vessels are correctly matched?, (a) 1-Pulmonary artery–Carries blood to the body, (b) 2-Superior and inferior vena cava–Carries blood to lungs, (c) 3-Aorta–Carries blood from lungs, (d) 4-Pulmonary veins–Carries blood from lungs, , 12. A person was found to have reduced level of reabsorption of water and glucose due to, kidney damage. Which of following labelled parts would be the site of damage for this, patient ?, Q, , P, , R, , (a) Q, (c) S, , (b) P, (d) R, , SAMPLE PAPER 1, , S

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66, , CBSE Sample Paper Science Class X (Term I), , 13. High blood pressure is caused by the, (a) constriction of ventricles, (b) constriction of arterioles, (c) constriction of veins, (d) constriction of capillaries, , 14. The overall process of breakdown of glucose in both aerobic and anaerobic respiration, is summarised below. Identify the correct option regarding the following labels., Glucose, (6-carbon, molecule), , Absence of, oxygen, (ii), , Ethanol + Carbon dioxide + Energy, (2-carbon molecule), , (i), Pyruvate, (3-carbon, molecule, +, Energy), , Lack of oxygen, (iii), , Lactic acid + Energy, (3-carbon molecule), , Presence of, oxygen, Carbon dioxide +, (iv), Water + Energy, , (a) Process (i) occurs in mitochondria in the absence of oxygen, (b) Process (iv) occurs in mitochondria in the presence of oxygen, (c) In the absence of oxygen, formation of ethanol, carbon dioxide and energy occur in, bacteria (ii), (d) Process (iii) occurs in blood cells during heavy exercise, , 15. Which of the following statement is true about heart?, Vena cava receiving, blood from, upper body, , Right atrium, Vena cava receiving, blood from, lower body, Right ventricle, , Aorta, Pulmonary, arteries, Pulmonary, veins, Left atrium, Valves, , Left ventricle, , SAMPLE PAPER 1, , Interventricular septum(dividing wall), , (a) Left atrium receives oxygenated blood from different parts of body, while right atrium, receives deoxygenated blood from lungs, (b) Left ventricle pumps oxygenated blood to different body parts, while right ventricle pumps, deoxygenated blood to lungs, (c) Left atrium transfers oxygenated blood to right ventricle which sends it to different body, parts, (d) Right atrium receives deoxygenated blood from different parts of the body, while right, ventricle pumps oxygenated blood to different parts of the body

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67, , CBSE Sample Paper Science Class X (Term I), , 16. Observe the diagram of human respiratory system., C, , B, , A, D, , Match the labelling referred in Column I and correlate it with Column II., Column I, , Column II, , A., , 1. These are the main passageway into the lungs., , B., , 2. They deliver air to tiny air sacs called alveoli., , C., , 3. It is also known as windpipe., , D., , 4. It is the passage way between pharynx and trachea., , Codes, A, (a) 2, (c) 1, , B, 3, 4, , C, 4, 3, , D, 1, 2, , A, (b) 3, (d) 1, , B, 2, 2, , C, 1, 3, , D, 4, 4, , 17. Which phenomenon is depicted in the diagram given below?, Star, , Observer, , (a) Diffraction of light, (c) Refraction of light, , (b) Scattering of light, (d) Reflection of light, , 18. Identify the optical element which forms a real magnified image and virtual magnified, , 19. A real image of same size as that of object is formed by a convex lens. The object must, be at a distance of, (a) u < f, (c) f < u < 2 f, , (b) u = f, (d) u = 2 f, , SAMPLE PAPER 1, , image of an object in front of it., (a) A thin diverging lens, (b) A thin converging lens, (c) A thick diverging mirror, (d) A thick converging mirror

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68, , CBSE Sample Paper Science Class X (Term I), , 20., Medium A, Medium B, , Observe the above figure. Which of the following statement would be correct?, (a) Medium B has more refractive index than medium A., (b) Medium A is optically denser medium as compared to medium B., (c) Medium A and medium B are essentially the same medium but angle of incidence is, critical angle., (d) Medium A is denser, so it is optically rarer medium., , 21. Refractive index of water with respect to air is 1.33, and refractive index of diamond, with respect to air is 2.42. Based on this data, arrange the wavelength of light through, them in increasing order., (a) Wavelength in air < Wavelength in diamond < Wavelength in water, (b) Wavelength in water < Wavelength in air < Wavelength in diamond, (c) Wavelength in diamond < Wavelength in water < Wavelength in air, (d) Wavelength in air < Wavelength in water < Wavelength in diamond, , 22., Black, paper, , The focal length of above lens is 10 cm. One-half of lens is covered with black paper. Which, of the following is correct?, (a) The image formed is half of original image in height, (b) A complete image is formed but of less intensity and brightness, (c) Image is formed only above the principal axis, (d) No image is formed due to black paper, , 23. Red colour is used for stop sign in the traffic signal. Which phenomenon is involved in, , SAMPLE PAPER 1, , this ?, (a) Dispersion of white light into its constituent colours, (b) Refraction of light due to atmosphere, (c) Reflection of light due to windshield of car, (d) Scattering of light by particles present in air, , 24., Reflected ray, , A ray is reflected by a plane mirror as shown above. The angle of incidence for the, above reflected ray is, (a) 90°, (b) 0°, (c) 180°, (d) 45°

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69, , CBSE Sample Paper Science Class X (Term I), , Section B, Section B consists of 24 questions (Sl. No. 25 to 48). Attempt any 20 questions from this section. The first, attempted 20 questions would be evaluated., , 25. The table provides the pH value of four solutions, P, Q, R and S., Solutions, , pH value, , P, , 3, , Q, , 10, , R, , 5, , S, , 12, , Which of the following correctly represents the arrangements of solutions in decreasing, order of the concentration of hydrogen ions?, (a) P > Q > R > S, , (b) S > Q > R > P, , (c) P > R > Q > S, , (d) P < S < Q < R, , 26. A student performed the following four experiments,, CuSO4 (aq), , CuSO4 (aq), Zn, , Al, , II, , I, , CuSO4 (aq), , CuSO4 (aq), , Cu, , Fe, , IV, , III, , In which experiment(s) would he find the formation of a solid deposition?, (a) I and II, , (b) II and III, , (c) I, II and III, , (d) Only IV, , 27. The table shown below gives information about four substances: A, B, C and D., Hardness, , Ductility, , Lustrous, , A, , Hard, , Yes, , Yes, , B, , Soft, , No, , Yes, , C, , Hard, , Yes, , Yes, , D, , Soft, , Yes, , Yes, , Identify the non-metal from the above given substances., (a) A, C, , (b) B, D, , (c) Only B, , (d) None of these, , SAMPLE PAPER 1, , Substances

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70, , CBSE Sample Paper Science Class X (Term I), , 28. Copper (II) hydroxide on decomposition, gives two products. Which of the following, statement is correct regarding the balanced chemical equation for this process?, (a) 2 moles of copper (II) hydroxide produces 2 moles of cupric oxide and 1 mole of water, (b) 1 mole of copper (II) hydroxide produces 2 moles of cupric oxide and 1 mole of water, (c) 1 mole of copper (II) hydroxide produces 1 mole of cupric oxide and 1 mole of water, (d) 2 moles of copper (II) hydroxide produces 1 mole of cupric oxide and 2 moles of water, , 29. Equal length of magnesium ribbons are taken in test tubes A and B. Hydrochloric acid, ( HCl) is added to test tube A, while acetic acid (CH 3 COOH) is added to test tube B., Amount and concentration taken for both the acids are same. Which of the following, observation(s) is/are correct?, I. Change in colour is observed in both test tubes., II. Fizzing occurs in both test tubes., III. Evolution of hydrogen gas in both test tubes., IV. White precipitate is formed in test tube A., (a) I and III, (b) II and III, (c) I and IV, (d) I, II and III, , 30. Four samples, A, B, C and D were taken and their pH value was recorded. The graph, was drawn on the basis of pH value with respect to four samples., 14, pH, value, , 7, , 0, , A, , B, , Which sample represents milk of magnesia?, (a) A, (b) B, , C, , D, , (c) C, , (d) D, , Direction (Q. No. 31 to 34) Consist of two statements – Assertion (A) and Reason (R). Answer these, questions selecting the appropriate option given below :, (a) Both A and R are true and R is the correct explanation of A., (b) Both A and R are true, but R is not the correct explanation of A., (c) A is true, but R is false., (d) A is false, but R is true., , 31. Assertion The balancing of chemical equation is based on law of conservation of mass., , SAMPLE PAPER 1, , Reaction In a balanced equation, the total number of atoms of each elements must be, equal on both sides of the equation., , 32. Assertion Baking soda is an acid which creates acidity in the stomach., Reason Baking soda has a pH around 8.3., , 33. Assertion The inner lining of the small intestine have numerous finger-like projections, called villi., Reason The villi helps in breakdown of protein and lipids., , 34. Assertion Out of water, mustard oil, glycerine and kerosene, the ray of light incident, obliquely at same angle would bend most in glycerine., Reason Glycerine has lowest refractive index.

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71, , CBSE Sample Paper Science Class X (Term I), , 35. The table given below shows the displacement reaction of a few elements, A, B, C and, D with following solutions one by one., Metal, , Copper sulphate, , Zinc sulphate, , Silver nitrate, , A, , P, , O, , P, , B, , P, , P, , P, , C, , O, , O, , P, , D, , O, , O, , O, , Arrange the metals A, B, C and D in order of increasing reactivity., (a) A > B > C > D, (b) D > C > B > A, (c) D < C < A < B, (d) B < A < C < D, , 36. Pancreatic enzymes helps in the digestion of, (a) fats and proteins, (c) carbohydrates, proteins and fats, , (b) carbohydrates and proteins, (d) carbohydrates and fats, , 37. Which of the following statement is correct about bile?, (a) Secreted by liver and stored in gall bladder, (b) Secreted by pancreas and stored in liver, (c) Secreted by salivary gland and stored in saliva, (d) Secreted by gastric glands and stored in stomach, , 38. What is the importance of having many blood vessels in the walls of the small intestine ?, (a) The blood vessels absorbs water from undigested food, (b) The blood vesels carry the digestive juices, (c) It enables the efficient absorption of digested food, (d) It takes the absorbed food to each cell for obtaining energy, , 39. Light rays from a distant source are converged at a point 20 cm in front of a concave, mirror. Where should an object be placed, so that size of its image is equal to the size of, the object?, (a) 40 cm in front of concave mirror, (b) 20 cm in front of concave mirror, (c) Between 20 cm and 40 cm in front of concave mirror, (d) More than 40 cm in front of concave mirror, , 40. If two thin lenses of focal length 20 cm and - 25 cm are combined to form a single lens,, (b) 1 D, (d) 9 D, , 41. During the breathing cycle, when air is taken in and let out, the lungs always contain, (a) total volume of air, (c) expiratory reserve volume, , (b) tidal volume, (d) residual volume of air, , 42. Anam choked when she was taking her lunch. What could have happened?, (a) She swallowed food that was not completely digested, (b) The salivary gland have not secreted enough amylase enzyme, (c) Some food particles entered her windpipe, (d) Starch is not digested properly in her mouth, , SAMPLE PAPER 1, , then the power of combination is, (a) 5 D, (c) - 4 D

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72, , CBSE Sample Paper Science Class X (Term I), , 43., A, A', B, , B' F, , C, , An object AB is standing 40 cm in front of diverging mirror. Its image appears 15 cm, behind the mirror. The focal length of the mirror will be, (a) + 12 cm, (b) - 12 cm, (c) + 24 cm, (d) - 24 cm, , 44. A 6 cm tall object is placed perpendicular to the principal axis of a convex lens of focal, length 25 cm. The distance of the object from the lens is 40 cm. Find the size of the, image formed., (a) + 66.67 cm, (b) - 10 cm, (c) - 66.67 cm, (d) + 10 cm, , 45., A, , B, , The above optical element is a spherical mirror which produces an image of, magnification -1 on a screen placed at a distance of 50 cm from the mirror. Find the, distance of the image from the object., (a) 25 cm, (b) - 50 cm, (c) 50 cm, (d) 0, , 46. If the speed of light in air is 3 ´ 10 8 m/s and speed of light in water is 2.2 ´ 10 8 m/s, then, the refractive index of water is, (a) 1.4, (c) 1.5, , (b) 2.4, (d) 1.22, , 47. Two media are joined together in contact and a ray of light travels as shown in the figure., 45º, , Medium 1, , SAMPLE PAPER 1, , 30º Medium 2, , Then, the refractive index of medium 1 with respect to medium 2 is, (a) 3, (c), , 2, 3, , 3, 2, 1, (d), 2, (b)

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73, , CBSE Sample Paper Science Class X (Term I), , 48. Zinc granules were added to zinc sulphate, copper sulphate, aluminium sulphate and, iron sulphate solution as shown below., , Zinc, sulphate, Zinc, I, , Copper, sulphate, Zinc, II, , Aluminium, sulphate, , Iron, sulphate, , Zinc, III, , Zinc, IV, , Which of the following observation is correct?, (a) In beaker II, zinc will displace copper from copper sulphate solution., (b) In beaker III, zinc will displace aluminium from aluminium sulphate solution., (c) In beaker IV, zinc will not displace iron from its sulphate solution., (d) All of these are correct., , Section C, This Section C consists of three Cases followed by questions. There are a total of 12 questions in this, section. Attempt any 10 questions from this section. The first attempted 10 questions would be evaluated., , Case I. Four groups of students were assigned on separately the experiment of interaction of, iron nail with a solution of copper sulphate. Each group recorded the observations as given, below in the table., Group of, students, , Initial colour Final colour Change in the, of solution, of solution, iron nail, , A, , Blue, , Colourless, , Brown coat, , B, , Green, , Green, , Brown coat, , C, , Blue, , Blue, , Brown coat, , D, , Blue, , Light green, , Brown coat, , 49. Which type of reaction is observed in given experiment ?, (a) Combination, (c) Double displacement, , (b) Displacement, (d) Decomposition, , (a) A, (c) C, , (b) B, (d) D, , 51. The brown coating on iron nail is due to, (a) rust, (c) oxidation, , (b) copper deposition, (d) All of these, , SAMPLE PAPER 1, , 50. Which group of students recorded all the observations correctly?

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74, , CBSE Sample Paper Science Class X (Term I), , 52. Which of the following statement is correct?, (a) Iron is more reactive than copper, (b) Copper is more reactive than iron, (c) The colour of iron sulphate solution is blue, (d) The colour of copper sulphate solution is green, , Case II. Excretion is the biological process by which an organism removes the metabolic wastes, from the body. The main organs involved in the human excretory systems are pair of kidneys, a, pair of ureters, a urinary bladder and a urethra. The figure given below represents the human, excretory system., , Kidneys, , Ureter, , Urinary, bladder, , 53. Where can one find kidneys in a human body?, (a) At the back, behind the lungs, (c) Near belly button, , (b) At the back, above the waist, (d) Behind pancreas gland, , 54. The muscular tubes which take the urine from the kidneys to the bladder are, (a) urinary bladder, , (b) ureters, , (c) urethra, , (d) nephrons, , 55. Choose the incorrect pair., (a) Storage of urine—Urinary bladder, (c) Filtration units—Kidney, , (b) Transport of urine—Ureter, (d) Collecting filtered urine—Glomerulus, , 56. Which among the following is/are not the function of kidney?, , SAMPLE PAPER 1, , I. Cleaning of blood by filtering it and removing waste products., II. Regulation of minerals in the body and production of hormones., III. Providing energy for the flow of blood., IV. Maintaining higher concentration of electrolytes., Codes, (a) I and III, (b) II and III, (c) Only II, (d) III and IV, Case III. Vinita demonstrated an activity to prove that white light is made up of many colours., She set up the experiment as shown, White, light, , A, , Spectrum, of, different, colours, , She observed that white light gets split into raindows colours. Some deviates more while some, deviates less.

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75, , CBSE Sample Paper Science Class X (Term I), , 57. Which optical element A is used by Vinita to perform this experiment?, (a) Soap bubble, (c) Prism, , (b) Rectangular glass slab, (d) Diverging lens, , 58. She observes that there are seven colours in the spectrum, then which colour suffers, least deviation and most deviation, respectively?, (a) Red colour suffers least deviation while violet colour suffers most deviation., (b) Violet colour suffers least deviation while red colour suffers most deviation., (c) Yellow colour is mean colour, so it suffers minimum deviation., (d) Yellow colour is mean colour, so it suffers most deviation., , 59. Four colour rays are shown in figure. Which colour has more speed in the prism ?, , P, Q, R, S, , Beam of, light, , (a) P, , (b) Q, , (c) R, , (d) S, , 60. Among the seven colours observed in the experiment, which colour is having the, shortest wavelength?, (a) Red, (b) Blue, , (c) Yellow, , (d) Violet, , SAMPLE PAPER 1

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OMR SHEET, , SP 1, , Roll No., Sub Code., , Student Name, , Instructions, Use black or blue ball point pens and avoid Gel & Fountain pens for filling the OMR sheet., Darken the bubbles completely. Don’t put a tick mark or a cross mark, half-filled or over-filled bubbles will not be read, by the software., Correct, , ✔, , ✗, , Incorrect, , Incorrect, , Incorrect, , Do not write anything on the OMR Sheet., Multiple markings are invalid., , 1, , 21, , 41, , 2, , 22, , 42, , 3, , 23, , 43, , 4, , 24, , 44, , 5, , 25, , 45, , 6, , 26, , 46, , 7, , 27, , 47, , 8, , 28, , 48, , 9, , 29, , 49, , 10, , 30, , 50, , 11, , 31, , 51, , 12, , 32, , 52, , 13, , 33, , 53, , 14, , 34, , 54, , 15, , 35, , 55, , 16, , 36, , 56, , 17, , 37, , 57, , 18, , 38, , 58, , 19, , 39, , 59, , 20, , 40, , 60, , Check Your Performance, Total Questions:, Total Correct Questions:, , If Your Score is, , Score Percentage =, , Total Correct Questions, Total Questions, , × 100, , Less than 60%, > Average (Revise the concepts again), Greater than 60% but less than 75% > Good (Do more practice), Above 75%, > Excellent (Keep it on)

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77, , CBSE Sample Paper Science Class X (Term I), , Answers, 1. (b), 11. (d), , 2. (c), 12. (d), , 3. (b), 13. (b), , 4. (d), 14. (b), , 21. (c), 31. (a), 41. (d), , 22. (b), 32. (d), 42. (c), , 23. (d), 33. (c), 43. (c), , 24. (b), 34. (c), 44. (b), , 51. (b), , 52. (a), , 53. (b), , 54. (b), , 5. (b), 15. (b), 25. (c), , 6. (c), 16. (a), 26. (c), , 7. (c), 17. (c), 27. (c), , 8. (d), 18. (b), 28. (c), , 9. (a), 19. (d), 29. (b), , 10. (c), 20. (b), 30. (b), , 35. (c), 45. (d), , 36. (c), 46. (a), , 37. (a), 47. (c), , 38. (d), 48. (a), , 39. (a), 49. (b), , 40. (b), 50. (d), , 55. (c), , 56. (d), , 57. (c), , 58. (a), , 59. (a), , 60. (d), , EXPLANATIONS, 1. When potassium sulphate solution was added, to barium chloride solution, then white, precipitate of barium sulphate is formed along, with potassium chloride., K2SO4( aq) + BaCl 2( aq) ¾® BaSO4( s), Potassium sulphate, , Barium chloride, , Barium sulphate, (white ppt.), , +, , 2KCl( aq), Potassium chloride, , 2. The electrolysis of water forms two gases,, hydrogen and oxygen., 2H 2O ( l ) ¾Electrolysis, ¾ ¾ ¾¾® 2 H 2( g ) + O 2( g ), , 4. The element (X) is zinc which reacts with both, acid and base., Zn( s) + H 2SO 4 ( aq) ¾® ZnSO 4 ( aq) + H 2( g ), Sulphuric acid, , Zinc sulphate, , Hydrogen, , Zn( s) + 2NaOH( aq) ¾® Na 2ZnO 2( aq) + H 2( g ), Zinc, , Sodium hydroxide, , Sodium zincate, , Silver nitrate, , Hydrogen, , 5. Lemon juice (b) contain citric acid. Acids have, pH value below 7. So, addition of lemon juice is, responsible for the decline in pH value in the, given graph., , 6. The substance which gets oxidised acts as, reducing agent. C is oxidised in the given, reaction by addition of oxygen atom, therefore, also acts as reducing agent., 7. The reaction between potassium bromide and, silver nitrate forms two products that are silver, bromide and potassium nitrate., , Silver bromide, , +, , KNO 3 ( aq), Potassium nitrate, , This reaction is an example of double, displacement reaction as Ag and K are, displaced by each other., 8. Sodium carbonate is prepared by reaction, between carbonic acid ( H2CO3 ) as parent, acid and sodium hydroxide (NaOH) as parent, base., 2NaOH, + H 2CO 3 ¾®, Carbonic acid, , Na 2CO 3, Sodium carbonate, , + 2H 2O, Water, , 9. A substance ‘X’ which turns blue litmus red is, an acid and phenolphthalein becomes, colourless in presence of acid., Whereas methyl orange gives yellow colour in, basic solution. Vanilla and clove are olfactory, indicators, their smell can be detected in, presence of acid only., 10. Evaporation of water is endothermic process, because in this process, heat is required for, conversion of water into vapours., 11. 1-Pulmonary artery carries blood from the, heart to the lungs., 2-Superior and inferior vena cava carries, deoxygenated blood from the body to the heart., 3-Aorta carries blood from the heart to the body., 4-Pulmonary veins carries blood from lungs to, the heart., 12. The correct labelling is, P = Efferent arteriole, Q = Glomerulus, R = Capillaries, S = Collecting duct, , SAMPLE PAPER 1, , Caustic soda and baking soda are bases which, can increase pH value and common salt, solution is neutral in nature., , ¾® AgBr( s), , KBr( aq), Potassium bromide, , Sodium hydroxide, , 3. Chemical equation (b) is balanced one., The balanced chemical equation is that in which, the total number of atoms of each element are, equal on both sides of the equation., AlCl 3 + 3NH 4OH ¾® Al(OH)3 + 3 NH 4Cl, , Zinc, , AgNO 3 ( aq) +

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78, , CBSE Sample Paper Science Class X (Term I), , The capillaries (R) around the kidney tubule, reabsorbing some useful substances from the, initial filtrate like glucose, amino acids, water, as the urine flows along the tubule., 13. High blood pressure or hypertension is caused, by the constriction of arterioles, which results in, increased resistance to blood flow. It can lead to, the rupture of an artery and internal bleeding., 14. Process (iv) occurs in mitochondria in the, presence of oxygen., Breakdown of pyruvate using oxygen takes, place in the mitochondria. This process breaks, up the three-carbon pyruvate molecule to give, three molecules of carbon dioxide and water., The incorrect options can be corrected as, Process (i) occurs in cytoplasm in the, presence or absence of oxygen., In the absence of oxygen, formation of, ethanol, carbon dioxide and energy occur in, yeast (ii)., Process (iii) occurs in muscle cells during, heavy exercise., l, , l, , l, , 15. Oxygen-rich blood from lungs enters the left, atrium. The left atrium will relax when it is, collecting this blood. It then contracts, and the, left ventricle (next chamber) expands so that, the blood is transfered to it. Contraction of left, ventricle pumps the oxygenated blood to the, various parts of body., Deoxygenated blood from body enters right, atrium as it expands. Now, as the right atrium, contracts, the right ventricle (lower chamber), dilates resulting in transfer of blood to right, ventricle., , SAMPLE PAPER 1, , 16. The correct labelling is, (A)—Bronchioles, (B)—Trachea, (C)—Larynx, (D)—Bronchi, (A) Bronchi are subdivided into smaller tubes, and form structure called bronchioles. Each, bronchioles finally terminates into alveoli, that provide surface for the exchange of, gases., (B) Trachea is also called windpipe which, serves as passage for air to the lungs., (C) Larynx is also called voice box. It is the, passage way of air between pharynx and, trachea., (D) Trachea is divided into two smaller tubes, called bronchi, which are main, passageway into the lungs., , 17. When the light from a star enters the earth’s, atmosphere, it undergoes multiple refraction, and its path changes multiple times due to, bending of light towards the normal., Therefore, the apparent position of the star is, slightly different from its actual position., 18. A thin converging lens forms a real magnified, and virtual magnified image., When object is placed between F and 2F,, it forms real and magnified image but, inverted., When object is placed between optical centre, and F, it forms virtual, erect and magnified, image., 19. Convex lens forms a real image of same size as, that of object when the object is placed at its, centre of curvature, means object distance,, u = 2 f., 20. According to the given figure, light ray coming, from medium B enters medium A and bends, towards normal which means medium A is, optically denser than medium B., As the medium A is optically denser, so its, refractive index is more than that of B., 21. As we know that,, Refractive index µ, , 1, Wavelength, , \ ma < mw < md, Þ ld < lw < la, Wavelength of light in diamond is smallest, while wavelength of light in air is largest., 22. When half of lens is covered with black, paper, then the image formation is shown, below, A, F, B, , 2F, , B', , 2F, , F, A', , Lens formed a complete image of the object,, but the intensity and brightness of image will, be reduced because some rays cannot pass, through covered portion of lens., 23. Traffic signals are of red colour because red, light is least scattered and enters into the eye, with less loss of intensity. Due to this reason,, observer can see red signal from a very far, distance.

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79, , CBSE Sample Paper Science Class X (Term I), , 24. The angle of incidence for the given reflected, light is 0°. The ray diagram is shown below, Reflected ray, Incident ray, , 25. Lower the pH value of a substance, higher the, concentration of hydrogen ions., H+ ion concentration decreases as the pH, value increases., So, the decreasing order of concentration of, hydrogen ions of P, Q, R, and S is P > R > Q >, S., , The inner lining of the small intestine have, numerous finger-like projections called villi., These villi increases the surface area for, absorption. The villi are richly supplied with, blood vessels which takes the absorbed food to, each and every cell of the body, where it is, utilised for obtaining energy, building up new, tissues and the repair of old tissues., 34. A is true, but R is false because the refractive, index of glycerine is highest among the given, materials, so the ray of light incident obliquely, at same angle would bend most in case of, glycerine., , 27. As non-metals are soft and non-ductile in, nature. They are non-lustrous but iodine is a, non-metal which is lustrous in nature. Hence,, B is a non-metal among other options., , 35. B is the only metal which shows displacement, reaction in all three given solution of copper,, zinc and silver. This indicates that B is more, reactive than rest of metals and D is least, reactive as it does not show any displacement, reaction with given three solutions. A shows, displacement reaction in two solution while C, shows in only one solution. Therefore, A is, more reactive than C but less reactive than B., Hence, the increasing order of reactivity is, D<C<A<B, , 28. On decomposition of 1 mole of copper (II), hydroxide, it gives 1 mole cupric oxide and 1, mole water., , 36. The pancreatic enzymes are released in small, intestine, which is the site for complete, digestion of carbohydrates, proteins and fats., , 26. In I, II and III experiments, he find the, formation of a solid deposition because Al, Zn, and Fe are more reactive than Cu. They will, replace Cu from its sulphate solution and Cu, will deposit as solid., , D, Cu(OH)2 ¾¾, ® CuO + H 2O, , All elements are already balanced in this, equation. So, (c) is the correct answer, 29. When metal reacts with acid, there is, formation of salt and hydrogen gas., Metal + Acid ¾® Salt + Hydrogen gas, This hydrogen gas is responsible for fizzing, that occur in both test tubes. So, II and III are, correct observations., 30. Milk of magnesia is basic in nature and have, pH value around 10.5. So, according to bar, graph, only B have pH value above 7. Hence,, B represents milk of magnesia as their pH, value is higher than 7., , The balancing of equation follows law of, conservation of mass which states that total, mass of all atoms is same before and after the, reaction means mass is conserved., 32. A is false but R is true., Baking soda is a base which has pH value, around 8.3., 33. A is true, but R is false., , 38. The villi in the small intestine are supplied with, blood vessels which takes the absorbed food to, each and every cell of the body, where it is, utilised for obtaining energy, building up new, tissues and the repair of old tissues., 39. Light rays from a distant source converge at, 20 cm in front of a concave mirror, this means, 20 cm is the focal length of that mirror., Therefore, to get an image of same size of, object, the object should be placed at centre of, curvature, i.e. 40 cm in front of concave mirror., 40. Given, f1 = 20 cm and f2 = - 25 cm, 100, We know that, P =, f (in cm), 100, \, P1 =, =5D, 20, 100, and, P2 =, =-4D, - 25, Power of combination, P = P1 + P2 = 5 D - 4 D, Þ, , P = 1D, , SAMPLE PAPER 1, , 31. Both A and R are true and R is the correct, explanation of A., , 37. Bile juice is secreted by liver and stored in the, gall bladder. Bile salts breakdown the large fat, globules into smaller globules increasing the, efficiency of enzymes action, i.e. emulsification.

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80, , CBSE Sample Paper Science Class X (Term I), , 41. During the breathing cycle, when air is taken, in and let out, the lungs always contain a, residual volume of air, so that there is, sufficient time for oxygen to be absorbed and, for the carbon dioxide to be released., 42. A cartilage flap, epiglottis is present in the, throat behind the tongue, which prevents the, entry of food particles into the windpipe., While swallowing food epiglottis moves to, block the entrance of food into the windpipe., Sometimes, food might enter into windpipe, and cause choking. Thus, Anam choked due to, entry of food particles in her windpipe., 43. Given, object distance, u = - 40 cm, , or, or, , 1 1 1, + =, u v, f, 1, 1, 1, +, =, - 40 15, f, 1, 5, =, f 120, f = + 24 cm, , Focal length of lens, f = 25 cm, Object distance, u = - 40 cm, 1 1 1, Using lens formula, = f v u, 1, 1, 1, Þ, = 25 v ( - 40 ), 200, cm, or, v=, 3, h, v, Now, magnification, m = i =, ho u, 200, hi, =, 6 3 ´ ( - 40 ), , 3 ´ 10 8, 2.2 ´ 10 8, , = 1.4, , 47. Given, angle of incidence, i = 45°, Angle of refraction, r = 60°, 45º, Medium 1, 30º, , 60º, , Medium 2, , 49. The change in colour of initial and final, solution and the deposition of layer on element, indicates the occurrence of displacement, reaction., 50. The blue colour of copper sulphate changes, into light green colour solution due to, formation of ferrous sulphate by displacement, reaction., Fe( s) + CuSO 4 ( aq) ¾® FeSO 4 ( aq) + Cu( s), Iron, , Copper sulphate, (Blue), , Ferrous sulphate, (Light green), , Copper, , The displaced copper gets deposited on iron, nail and form brown coating on it., , hi = - 10 cm, , 45. The mirror is concave mirror., , SAMPLE PAPER 1, , m=, , 48. According to reactivity series, aluminium is, more reactive than zinc. So, zinc cannot, displace aluminium, but iron and copper are, less reactive than zinc. So, they can be easily, displaced by zinc. So, the correct observation, is (a)., , 44. Given, height of object, ho = 6 cm, , Þ, , Þ, , va, vw, , \Refractive index of medium 1 w.r.t. medium 2,, sin i, (by Snell’s law), m=, sin r, 1, sin 45°, m=, Þ m= 2, Þ, 3, sin 60°, 2, 2, m=, Þ, 3, , Image distance, v = 15 cm, By using mirror formula, we get, , Þ, , \ Refractive index, m =, , Given, m = - 1, u = - 50 cm, -v, -v, Þ-1=, \ Magnification, m =, u, - 50, Þ, v = - 50 cm, \ The distance of image from the object, = - 50 - ( - 50 ) = 0, 46. Given, speed of light in air ( va ) = 3 ´ 10 8 m/s, 8, , Speed of light in water ( vw ) = 2.2 ´ 10 m/s, , Hence, D group of students recorded all the, correct observations., 51. The brown coating on iron nail is due copper, deposition because according to reactivity, series, iron is more reactive than copper, so, it, will displace copper from it’s sulphate solution, and then solid copper will get deposited on, iron nail., 52. According to reactivity series, iron is more, reactive than copper as it is placed above copper, in reactivity series of metals.

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81, , CBSE Sample Paper Science Class X (Term I), , 53. In humans, the kidneys are the main excretory, organs. These bean-shaped organs are located in, abdomen, one on either side of backbone above, the waist., 54. The urine forming in each kidney eventually enters, a long muscular tube, the ureter, which connects, the kidneys with the urinary bladder., 55. Each kidney has large numbers of tiny filtration, unit called nephrons, which are closely packed, together. These are the structural and functional, units of kidney., 56. Kidneys are involved in the cleaning of blood by, filtering it and removing waste products. It also, regulates minerals in our body and produced, certain hormones like vitamin-D and, , erythropoietin. Kidney also regulaes the pH, of blood and maintains homeostasis., 57. Prism is the optical element, which is used, in this experiment to get spectrum of white, light., 58. Red colour suffers least deviation because, the wavelength of red light is more than, rest of the colours and violet colour suffers, from most deviation due to its shorter, wavelength., 59. P has more speed in the prism because it, suffers least deviation., 60. Violet colour has the shortest wavelength, among rest of the colours in white light., , SAMPLE PAPER 1

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SAMPLE PAPER 2, SCIENCE, A Highly Simulated Practice Questions Paper, for CBSE Class X (Term I) Examination, , Instructions, (i) This paper is divided into three Sections:, (a) Section A – Contains 24 questions. Attempt any 20 questions., (b) Section B – Contains 24 questions. Attempt any 20 questions., (c) Section C – Contains 12 questions. Attempt any 10 questions., (ii) Each questions carries 0.80 mark., (iii) There is NO negative marking., Maximum Marks : 40, Time allowed : 90 Min., , Roll No., , Section A, This section consists of 24 multiple choice questions with overall choice to attempt any 20 questions. The, first attempted 20 questions will be considered for evaluation., , 1. Ajay took lead nitrate salt in a dry test tube. He heated the test tube. What would he, observed?, (a) Yellow coloured residue and brown fumes were observed, (b) White coloured residue with yellow fumes were observed, (c) Yellow precipitate with colourless residue was observed, (d) Brown coloured fumes with colourless residue was observed, , 2. Identify the colour of gas evolved in the following experiment., Gas evolved, Test tube holder, Boiling test tube, Potassium nitrate, , Burner, , (a) Colourless, , (b) Yellow, , (c) Whitish grey, , (d) Black

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83, , CBSE Sample Paper Science Class X (Term I), , 3., , Metal, NaOH, , Gas, , Metal salt, , Which of the following two combinations are correct?, Metal, , Gas evolved, , (i), , Al, , No, , (ii), , Ag, , No, , (iii), , Mg, , Yes, , (iv), , Zn, , Yes, , (a) (i) and (iii), (c) (ii) and (iv), , (b) (ii) and (iii), (d) (i) and (iv), , 4. Which of the following option correctly represents a balanced chemical equation?, (a) 2Na 2CO 3 ( s) + 2HCl( aq) ¾® 2NaCl( aq) + H 2O( c) + 2CO 2 ( g), (b) 3Na 2CO 3 ( s) + HCl( aq) ¾® 3NaCl( aq) + H 2O( l) + 3CO 2 ( g), (c) Na 2CO 3 ( s) + 2HCl( aq) ¾® 2NaCl( aq) + H 2O( l) + CO 2 ( g), (d) 3Na 2CO 3 ( s) + 2HCl( aq) ¾® 3NaCl( aq) + H 2O( l) + 3CO 2 ( g), , 5. The graph given below represents neutralisation reaction. The pH of solution changes, as we add excess of base to an acid., D, 14, pH, value 7, , C, A, , 0, , B, Volume of base, added, , Which letter denotes the area of the graph where both base and salt are present?, (a) A, (b) B, (c) C, (d) D, , 6. In the reaction of copper oxide with hydrogen,, CuO( s) + H 2 ( g) ¾® Cu( s) + H 2O( l), , Substance oxidised, , Reducing agent, , (a), , CuO, , Cu, , (b), , H2, , H2, , (c), , Cu, , CuO, , (d), , H 2O, , H2, , SAMPLE PAPER 2, , Which option in the given table correctly represents the substance oxidised and the, reducing agent?

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84, , CBSE Sample Paper Science Class X (Term I), , 7. The chemical reaction between methane and oxygen is, (a) displacement reaction, (b) combination reaction, (c) exothermic reaction, (d) precipitation reaction, , 8. Which of the given option correctly represents the parent acid and parent base of, ammonium chloride?, Parent acid, , Parent base, , (a), , NH3, , NaOH, , (b), , NH3, , (c), , HCl, HNO 3, , NaOH, , (d), , HCl, , NH4 OH, , 9. What happens when excess of CO 2 gas is passed through lime solution (lime water)?, (a) The milkiness of limewater disappears, (b) The milkiness of limewater changes from white to yellow, (c) The lime solution becomes hot, (d) The lime solution becomes cold, , 10. The bleaching powder gives smell of chlorine due to, (a) formation of chlorine on exposure to atmosphere, (b) unstability of bleaching powder, (d) formation of excess of chlorine, (d) displacement reaction, , 11. Observe the diagram of human respiratory system,, Nose, , Nasal, passage, , Pharynx, , (i), , Larynx, , Rings of, cartilage, (iii), , Bronchi, , Lung, Respiratory, bronchioles, , SAMPLE PAPER 2, , (iv), , (ii), , Select the option which gives correct identification and main function or/and, characteristics., (a) (i) Trachea - It is supported by complete cartilage rings, (b) (ii) Diaphragm - Relaxes and get back to its original shape during expiration, (c) (iii) Ribs - When we breathe out, ribs are lifted, (d) (iv) Alveoli - It filters air by fine hairs and mucus present in them

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85, , CBSE Sample Paper Science Class X (Term I), , 12. The table show nutrients present in four foods., Food, P, , Carbohydrate, , Fat, , Protein, , ü, , û, , ü, , Q, , û, , û, , ü, , R, , û, , ü, , û, , S, , ü, , ü, , û, , Which foods would both be partly digested in the stomach?, (a) P and Q, (b) P and R, (c) Q and S, , (d) R and S, , 13. Rings of cartilage are present in the throat to ensure that, (a) the air passage collapses, (c) the air is filtered entering the nostrils, , (b) the air passage does not collapse, (d) None of these, , 14. The given diagram shows the different stages of nutrition in Amoeba with labels (i) to (iv)., Nucleus, (i ), , Pseudopodia, Food particle, Food vacuole, , (ii ), , Food particle, , (iii ), , (iv ), , Undigested food, removed, , Identify the correct label with its characteristics., (a) (i) Ingestion – It is the process of eliminating undigested food, (b) (ii) Digestion – The food get readily absorbed by the cytoplasm, (c) (iii) Absorption – The cell membrane ruptures and absorbs food, (d) (iv) Egestion – The undigested food is removed from the body, , 15. Identify the phase of respiration which is represented in the diagram given below., , Lung, Diaphragm, , SAMPLE PAPER 2, , Sternum, Ribs

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86, , CBSE Sample Paper Science Class X (Term I), , Arrow indicates the expansion of different parts shown., (a) When we breathe in, then the ribcage and diaphragm moves upward simultaneously, (b) When we breathe in, ribcage contracts and diaphragm relaxes, (c) When we breathe in, the downward movement of ribcage and upward movement of, diaphragm increase the chest cavity, (d) When we breathe in, the upward movement of ribcage as well as downward movement, of diaphragm increase the space in chest cavity, , 16. Nephron, functional unit of kidney, the structure that actually produces urine in the, process of removing waste and excess substances from the blood., A, , C, , B, , Renal, artery, Brach of, renal vein, D, Capillaries, , Match the labelling referred in Column I and correlate with the Column II., Column I, A, , 1., , It is network of small blood vessels, located at the beginning of the nephron., , B, , 2., , It finally gathers all the materials that has not returned to the blood through the, tubular membranes., , C, , 3., , Reabsorption of glucose, amino acids and major amount of water occurs in it., , D, , 4., , It is cup-like structure that filters blood from the urine., , Codes, A, (a), 4, (c), 1, , 17., , Column II, , B, 3, 3, , C, 2, 4, , D, 1, 2, , (b), (d), , A, 4, 4, , B, 3, 2, , C, 1, 1, , D, 2, 3, , Incident, ray, , SAMPLE PAPER 2, , 70º, A, , O, , B, , Principal, axis, , From the given figure, the refracted ray would travel, (a) along OB, (b) along OA, (c) undeviated, (d) at 20° to the direction of OB, , 18. A child knows that white light is coming from Sun but the sunlight that reaches Earth is, yellowish rather than white. This is due to scattering and sunlight becomes deficient in, (a) violet colour, (b) blue colour, (c) red and violet colours, (d) violet, indigo and blue colours

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87, , CBSE Sample Paper Science Class X (Term I), , 19. A ray of light travels from medium I to medium II. The figure shows the variation of, sine of angle of incidence in medium I with sine of angle of refraction in medium II., Some conclusions are drawn as follows :, , sin r, , q>45°, sin i, , I. Speed of light in medium I > Speed of light in medium II, II. Speed of light in medium I < Speed of light in medium II, III. Light travels from denser to rarer medium, Which of the following statement(s) is/are correct?, (a) Only I, (b) Only II, (c) I and III, (d) II and III, , 20., O, , f, , f, , f/2, , Examine the above figure and find the distance of image from lens., (a) f distance from left of lens, (b) f distance from right of lens, 3f, 3f, (c), distance from left of lens, (d), distance from right of lens, 2, 2, , 21. Which one of the following statement is correct about the refraction of light through a, glass prism?, (a) Incident ray bend towards the base but the emergent ray bends away from base of, prism., (b) Both incident and emergent rays bend towards the base., (c) Both incident and emergent rays bend parallel to the base., (d) Incident ray bends away from the base while emergent ray bend towards the base of prism., , 22., Glass of, window pane, , 40°, , (b), , (a), , Glass of, window pane, , (c), , Glass of, window pane, , 40º, , Glass of, window pane, , (d), , Glass of, window pane, , SAMPLE PAPER 2, , Figure shows a ray of light meeting the glass of the window of a car at an angle of, incidence of 40°. Complete ray diagram is

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88, , CBSE Sample Paper Science Class X (Term I), , 23. If we use a concave mirror of focal length 2.5 cm as a dentist’s mirror, the distance of, tooth from the mirror should be, (a) less than 2.5 cm than the focal length, (b) more than 2.5 cm than the focal length, (c) less than 5 cm than the focal length, (d) more than 5 cm than the focal length, , 24., , 2f2, , f1 O, , f1, , 2f2, , From the given figure, the image should be, (a) magnified and virtual, (b) magnified and real, (c) diminished and virtual, (d) diminished, real and inverted, , Section B, This section consists of 24 multiple choice questions with overall choice to attempt any 20 questions. In case, more than desirable number of questions are attempted, ONLY first 20 will be considered for evaluation., Step II, , 25. Glucose + O 2 ¾¾® X + H 2 O ¾¾® H 2 CO 3, Step I, , Identify the correct option from the given table which represents the type of reaction in, step I and acidic nature of H 2CO 3 in step II., Exothermic, , Acidic nature, , (a), , û, , ü, , (b), , ü, , û, , (c), , ü, , ü, , (d), , û, , û, , SAMPLE PAPER 2, , 26. In which year, the concentration of hydrogen ion is the highest?, 6, 5, 4, pH, value 3, 2, 1, 0, , 2008 2012 2016 2020, Soil pH value, , (a) 2008, (c) 2016, , (b) 2012, (d) 2020

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89, , CBSE Sample Paper Science Class X (Term I), , 27. The diagram shows the reaction between metal and dilute. acid., , Zn+, Dil.HNO3, , Ag+, Dil.HNO3, , (A), , (B), , Cu+, Dil.HNO3, , Mg+, Dil.HNO3, , (C), , (D), , Which of the following statement is incorrect regarding the reactions taking place in, four given test tubes?, (a) In test tube A, nitrous oxide is evolved, (b) In test tube B, nitrogen dioxide is evolved, (c) In test tube C, nitric oxide is evolved, (d) In test tube D, nitrogen dioxide is not evolved, , 28. The table shown below gives information about six elements A to F., Electronic configuration, , Formula of compound, , I., , A : 2, 1, , B : 2, 6, , A2 B, , II., , B : 2, 6, , C : 2, 7, , B 2C, , III., , C : 2, 7, , D : 2, 8, 3, , DC 3, , IV., , E : 2, 8, 6, , F : 2, 8, 8, 2, , FE 3, , Identify the compound which is wrongly formed., (a) I and II, (b) II and IV, (c) III and IV, (d) I and III, , 29. Raj observed that after the reaction between hydrochloric acid and sodium hydroxide,, sodium chloride and water are formed. Then, he searched about sodium chloride., Some of his statements about NaCl salt are given below :, It is also prepared by chlor-alkali process., It is a neutral salt, having pH value = 7., It is white crystalline solid., It is also called rock salt., , Select the correct statement(s)., (a) I, II and IV, (c) II and III, , (b) II, III and IV, (d) III and IV, , SAMPLE PAPER 2, , I., II., III., IV.

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90, , CBSE Sample Paper Science Class X (Term I), , 30. On adding few drops of universal indicator to four colourless solutions, A, B, C and D, having pH 2, 10, 9 and 7 respectively. Which of the following test tube is labelled with, correct colour?, , Red, (A ), , Green, , Blue, , (B), , Violet, , (C), , (a) A and B, (c) A, B and C, , (D), , (b) B and D, (d) A and C, , Direction (Q. No. 31 to 34) Consist of two statements – Assertion and Reason. Answer these questions, selecting the appropriate option given below :, (a) Both A and R are true and R is the correct explanation of A., (b) Both A and R are true, but R is not the correct explanation of A., (c) A is true, but R is false., (d) A is false, but R is true., , 31. Assertion Plaster of Paris is used by doctors for setting fractured bones., Reason When plaster of Paris is mixed with water, it forms hard material called, gypsum to support fractured bones., , 32. Assertion Refrigeration of cooked food takes place at low temperatures., Reason To cool down the cooked food quickly., , 33. Assertion All the veins carry deoxygenated blood from various organs to the heart., Reason Pulmonary artery carry deoxygented blood from the heart to the lungs., , 34. Assertion In diffused reflection, a parallel beam of incident light is reflected in, different directions., Reason The diffused reflection is due to the failure of laws of reflection., , 35. The table given below provides information related to the reaction of a few compounds, with hydrochloric acid and evolution of CO 2 in corresponding reaction., , SAMPLE PAPER 2, , Compounds, , Reactivity with HCl, , Evolution of CO 2, , ü, , ü, , I., , Na 2CO 3, , II., , ZnO, , ü, , û, , III., , KOH, , û, , û, , IV., , AgNO 3, , ü, , û, , Which of the following is incorrect option?, (a) I and IV, (b) I, II and III, (c) II and III, , (d) Only III, , 36. Which one of the following juices secreted in the human body does not contain any, enzyme?, (a) Salivary juice, (c) Gastric juice, , (b) Bile juice, (d) Pancreatic juice

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91, , CBSE Sample Paper Science Class X (Term I), , 37. Which type of respiration and reaction will take place in the germinating seeds in the, experimental setup showing CO 2 is evolved during respiration?, (a) In anaerobic respiration, reaction is, C 6 H12 O 6 + 6O 2 ¾® 6CO 2 + 6H2 O + Energy, (b) In aerobic respiration, reaction is, C 6 H12 O 6 + 6O 6 ¾® 2C 2 H2 OH + 2CO 2 + Energy, (c) respiration in the presence of oxygen, No Reaction, (d) In aerobic respiration, reaction is, C 6 H12 O 6 + 6O 2 ¾® 6CO 2 + 6H2 O + Energy, , 38. If trypsin is lacking in the pancreatic juices, which of the following events in the small, intestine will not takes place properly?, (a) Starch breaking down into sugars, (c) Digestion of proteins, , (b) Absorption of vitamins, (d) Emulsification of fats, , 39. An object is placed 25 cm in front of a concave lens of focal length 25 cm. Find the, location and nature of image., (a) At 5 cm from lens and real, (c) At - 0.5 cm from lens and erect, , 40., , P=8 D, , (b) At 12.5 cm from lens and virtual, (d) At -12.5 cm from lens and diminished, P=–10 D, , Find the power of combination of given lenses., (a) 18 D, (b) 2 D, (c) - 2 D, , (d) -18 D, , 41. Which of the following is protein digesting enzymes?, (a) Trypsin, Amylase, Pepsin, (b) Lipase, Trypsin, Amylase, (c) Pepsin, Trypsin, Bile, (d) Trypsin, Pepsin, Chymotrypsin, , 42. If Henle’s loop were absent from mammalian nephron, which one of the following to, , 43. The refractive index of a dense flint glass and for alcohol are 1.65 and 1.36 respectively, with respect to air. Then, the refractive index of dense flint glass with respect to alcohol, will be, (a) 1.10, (b) 1.21, (c) 1.31, (d) 1.5, , 44. A light ray is incident on a rectangular glass slab at an angle of 60°. The angle between, the ray coming out of the slab and the normal to the face of rectangular slab from, where it comes out is, (a) 30°, (b) 60°, (c) 90°, (d) 0°, , SAMPLE PAPER 2, , be expected?, (a) There will be no urine formation, (b) There will be hardly any change in the quality and quantity of urine formed, (c) The urine will be more concentrated, (d) The urine will be more dilute

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92, , CBSE Sample Paper Science Class X (Term I), , 45., A, , B, , D, , C, , F, 10 cm, , A square wire of side 1 cm is placed in front of concave mirror with one end at the, centre of curvature as shown. Find the length of image of side CD., 10, 11, 5, 6, (a), cm, (b), cm, (c) cm, (d) cm, 11, 10, 6, 5, , 46. At what distance, an object should be placed in front of a concave mirror of focal, length 20 cm to get an erect image?, (a) 10 cm, (b) 20 cm, , (c) 25 cm, , 47., , (d) 40 cm, , A, A, , Q, , R, , P, , S, C, , B, , In the above diagram, light is travelling through different media. It is noticed by a scientist, that ray QR is parallel to base CB. Which is the following statement would be correct?, (a) Angle of deviation is minimum,, (b) Angle of deviation and angle of prism are equal to angle of incidence., (c) Angle of emergence and angle of deviation are equal to angle of incidence., (d) Angle of deviation is maximum and equal to angle of incidence., , 48. A jewellery making unit tested few elements on the basis of their physical properties., Properties, , A, , B, , C, , D, , Malleable, , Yes, , No, , No, , Yes, , Ductile, , Yes, , No, , No, , Yes, , Lustre, , Yes, , No, , Yes, , No, , Melting point, , High, , Low, , Low, , High, , SAMPLE PAPER 2, , Which of the above elements were discarded for usage by the company?, (a) A, B and D, (b) B, C and D, (c) A and C, (d) B and C, , Section C, This Section C consists of three Cases followed by questions. There are a total of 12 questions in this section., Attempt any 10 questions from this section. The first attempted 10 questions would be evaluated., Case I. The sample of acetic acid is taken in a clean test tube. Now, a blue litmus paper strip is taken and a, drop of acetic acid is placed on litmus paper and the colour change is observed., Glass rod, Drop of, acetic acid, pH paper

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93, , CBSE Sample Paper Science Class X (Term I), , Another test tube is taken and 1 mL of acetic acid is added into it. A pinch of sodium bicarbonate ( NaHCO 3 ), is added to test tube containing acetic acid. Pass the evolved gas through the lime water and observe the, changes., , Lime water, Acetic acid, Sodium, bicarbonate, , 49. What is the effect on litmus paper after putting a drop of acetic acid?, (a) Blue litmus paper turns red, (c) Green colour is observed, , (b) Red litmus paper turns blue, (d) No change in any litmus paper, , 50. The odour of the acetic acid taken in test tube is, (a) sweet and fruity, (c) pungent, , (b) like rotten egg, (d) unpleasant, , 51. Complete the reaction involves in second experiment,, CH 3COOH( aq) + NaHCO 3 ( s) ¾® ?, (b) CH 3 COONa, H 2O, CO 2, (d) CH 3 OH, CO 2 , NaOH, , (a) CH 3 COONa, H 2O, (c) CH 4 , CO 2 , NaOH, , 52. What happens when excess of evolved gas is passed through lime water in experiment II?, (a) The solution becomes more milky, (b) The solution becomes yellow, (c) The solution becomes transparent, (d) No effect observed in solution, Case II. In a given activity, freshly prepared lime water was taken in two test tubes marked A and B., Air is blown through mouth in lime water in test tube B. In test tube A, syringe or pichkari is used to, pass air through the fresh lime water., , Pichkari, , Rubber, tube, , Tube, , Test tube, containing, lime water, , Lime water, , B, , 53. When air is blown from the mouth into a test tube containing limewater, the limewater, turns milky due to the presence of, (a) oxygen, (b) carbon dioxide, , (c) nitrogen, , (d) water vapour, , 54. Limewater turns milky due to the formation of, (a) water vapour, , (b) carbon dioxide, , (c) calcium carbonate, , (d) lactic acid, , SAMPLE PAPER 2, , A, , I. Air being passed into limewater with a pickhari/syringe., II. Air being exhaled into limewater.

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94, , CBSE Sample Paper Science Class X (Term I), , 55. Which of the following statements shows the correct observation for test tube-1 and, test tube-2., (a) Test tube - 1 – No change observed and test tube - 2 – Limewater turns milky, immediately, (b) Test tube -1 – Limewater turns milky immediately and test tube - 2 – No change, observed, (c) Test tube -1 –Limewater turns milky immediately and test tube - 2 – Limewater turned, milky after a long time, (d) Test tube -1 –Limewater turns milky after a long time and test tube- 2 – Limewater turns, milky immediately, , 56. Which of the following conclusion is true about the given experiment?, (i) Pichkari has more amount of CO 2 than our mouth, (ii) Lime water turns milky due to the presence of oxygen, (iii) The air exhaled through mouth turns limewater milky at very fast rate, (iv) Exhaled air contains more CO 2 as compared to atmospheric air, Choose the correct option., (a) (i) and (ii), (b) (iii) and (iv), (c) (ii) and (iii), (d) (i) and (iv), Case III. A student wants to know that what type of image, a spherical mirror forms. So, he placed object, at different locations in front of mirror and observed the images. Some images were real, some were, virtual. At a specific location, image and object size were same, while at other distances, it is either enlarged, or diminished. After understanding this, he observed that this phenomenon is known as reflection of light by, spherical surfaces., Hollow sphere, of glass, Principal, axis, , C, , C, , Pole, , Principal, axis, , Reflecting, surface, , 57. When he placed concave mirror in the experiment, then the image formed of object, placed at centre of curvature will be, (a) larger than the object, (c) highly enlarged but inverted, , (b) smaller than the object, (d) same size as that of object., , 58. A convex mirror has wider field of view. Which of the following is correct about it?, , SAMPLE PAPER 2, , (a) The image formed is much smaller than the object, (b) A large number of images can be seen, (c) The image formed is much closer to the mirror, (d) All of the above, , 59. A child standing in front of a magic mirror, finds her head of same size, middle portion, smaller and legs bigger than original. Which of the following is the correct sequence of, mirrors from the top?, (a) Plane, convex and concave, (b) Convex, concave and plane, (c) Concave, plane and convex, (d) Convex, plane and concave, , 60. To get an image larger than that of object one can use, (a) convex mirror but not a concave mirror, (b) concave mirror but not a convex mirror, (c) Either a convex mirror or a concave mirror, (d) a plane mirror

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OMR SHEET, , SP 2, , Roll No., Sub Code., , Student Name, , Instructions, Use black or blue ball point pens and avoid Gel & Fountain pens for filling the OMR sheet., Darken the bubbles completely. Don’t put a tick mark or a cross mark, half-filled or over-filled bubbles will not be read, by the software., Correct, , ✔, , ✗, , Incorrect, , Incorrect, , Incorrect, , Do not write anything on the OMR Sheet., Multiple markings are invalid., , 1, , 21, , 41, , 2, , 22, , 42, , 3, , 23, , 43, , 4, , 24, , 44, , 5, , 25, , 45, , 6, , 26, , 46, , 7, , 27, , 47, , 8, , 28, , 48, , 9, , 29, , 49, , 10, , 30, , 50, , 11, , 31, , 51, , 12, , 32, , 52, , 13, , 33, , 53, , 14, , 34, , 54, , 15, , 35, , 55, , 16, , 36, , 56, , 17, , 37, , 57, , 18, , 38, , 58, , 19, , 39, , 59, , 20, , 40, , 60, , Check Your Performance, Total Questions:, Total Correct Questions:, , If Your Score is, , Score Percentage =, , Total Correct Questions, Total Questions, , × 100, , Less than 60%, > Average (Revise the concepts again), Greater than 60% but less than 75% > Good (Do more practice), Above 75%, > Excellent (Keep it on)

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96, , CBSE Sample Paper Science Class X (Term I), , Answers, 1. (a), 11. (b), 21. (b), , 2. (a), 12. (a), 22. (b), , 3. (c), 13. (b), 23. (a), , 4. (c), 14. (d), 24. (c), , 5. (d), 15. (d), 25. (c), , 6. (b), 16. (a), 26. (c), , 7. (c), 17. (c), 27. (b), , 8. (d), 18. (d), 28. (b), , 9. (a), 19. (d), 29. (b), , 10. (a), 20. (a), 30. (d), , 31. (a), 41. (d), 51. (b), , 32. (c), 42. (d), 52. (c), , 33. (d), 43. (b), 53. (b), , 34. (c), 44. (b), 54. (c), , 35. (d), 45. (a), 55. (d), , 36. (b), 46. (a), 56. (b), , 37. (d), 47. (a), 57. (d), , 38. (c), 48. (b), 58. (d), , 39. (d), 49. (a), 59. (a), , 40. (c), 50. (c), 60. (b), , EXPLANATIONS, 1. When lead nitrate is heated, then it, decomposes to form yellow coloured lead, oxide, brown coloured fumes of nitrogen, dixoide and oxygen., D, 2Pb(NO 3 )2( s) ¾¾, ®, , 2PbO( s), Lead oxide (Residue), (Yellow), , Lead nitrate, , + 4NO 2( g ) + O 2( g ), Nitrogen, dioxide, (Brown), , Oxygen, , 2. When potassium nitrate is heated, then, colourless gas is evolved i.e. oxygen and, potassium nitrite formed as product., D, , KNO3 ¾® KNO2 + O2( g ), , Potassium, nitrate, , Potassium, nitrite, , Oxygen, , 3. The correct combination is (ii) and (iv) as :, (i) When Al reacts with NaOH, then salt of, aluminium is formed with evolution of, hydrogen gas., 2Al( s) + 6NaOH( aq) ® 2Na 3 AlO 3 + 3 H 2 ­, (ii) When silver and sodium hydroxide reacted, together, then no reaction takes place., Hence. No evolution of gas., , SAMPLE PAPER 2, , (iii) Magnesium and sodium hydroxide do not, react with each other. Hence, no evolution, of gas., (iv) When zinc is reacted with sodium, hydroxide, then zinc salt is formed with, evolution of hydrogen gas., Zn( s) + 2 NaOH( aq) ¾® Na 2ZnO 2 + H 2 ­, Hence, (ii) and (iv) are correct combination., 4. Na 2CO 3 ( s) + 2HCl( aq) ¾® 2NaCl( aq) +, H 2O( l ) + CO 2( g ), is balance equation because total number of, atoms of all the elements are equal on both, sides of an equation., , 5. The pH value of base is above 7. So, on, addition of base to an acid, neutralisation, reaction take place., Acid + Base ® Salt + Water, On addition of excess base, the pH of solution, rises above 7 due to presence of base along, with salt. Hence, D is the correct letter which, represents both base and salt., 6. The substance which gets oxidised is called, reducing agent. So, H 2 is oxidised into H 2O by, addition of oxygen atom and hence, H 2 is also, the reducing agent., 7. The reaction which are accompanied by the, evolution of heat is called exothermic reaction., When methane is reacted with oxygen, then, carbon dioxide and water are formed with, evolution of heat. Hence, this reaction is, exothermic in nature., CH 4 + 2O 2 ¾® CO 2 + 2H 2O + Heat, Methane, , Oxygen, , Carbon, dioxide, , Water, , 8. Ammonium chloride is formed by reaction, between hydrochloric acid (parent acid) and, ammonium hydroxide (parent base), HCl, , Hydrochloric, acid, , + NH 4OH ¾® NH 4Cl + H 2O, Ammonium, hydroxide, , Ammonium, chloride, , Water, , 9. When CO 2 gas is passed through limewater, it, turns lime water milky due to formation of, calcium carbonate. But, if CO2 is passed in, excess through lime solution, this milkiness, disappears due to formation of calcium, hydrogen carbonate which is colourless., Ca(OH)2( aq) + CO 2( g ) ® CaCO 3 ( s) + H 2O( l ), Limewater, , Carbon, dioxide, , Calcium, carbonate, (White), , Water, , CaCO 3 ( s) + H 2O( l ) + CO 2( g ) ¾®, Calcium, Carbonate, , Excess, , Ca(HCO 3 )2( aq), (Calcium hydrogen, carbonate), (Colourless)

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97, , CBSE Sample Paper Science Class X (Term I), , 10. Bleaching powder (CaOCl 2 ) reacts with carbon, dioxide present in atmosphere and produce, calcium carbonate and chlorine gas, that’s why, it gives smell of chlorine., CaOCl 2 + CO 2 ¾® CaCO 3 + Cl 2, Bleaching, Powder, , Carbon, dioxide, , Calcium, Carbonate, , Chlorine, gas, , 11. The diaphragm helps in the inspiration and, expiration of air in and out of the lungs., During expiration, the diaphragm relaxes and, returns to its previous shape and then the air is, pushed out of the lungs., The incorrect option can be corrected as, (i) Trachea It is supported by incomplete, cartilage rings., (iii) Ribs When we breathe out, ribs move, downwards., , flows into tubules by blood capillaries called, glomerulus. The blood passes through the, tubular part of nephron, where important, substances such as glucose, amino acids and a, major amount of water are selectively, reabsorbed by it. The collecting duct finally, gathers all the materials that has not returned, to the blood through the tubular membranes., 17. When a ray of light falls on the optical centre, of a lens, then after refraction, it passes, undeviated., 18. As violet, indigo and blue colours are scattered, most by Earth’s atmosphere because of their, shorter wavelength. So, the sunlight becomes, yellowish as it is deficient in violet, indigo and, blue colours., 19. Refractive index of a medium,, , (iv) Awedi Structure in lungs that facilitate, gaseous exchange., 12. The stomach lining secrete gastric juices and, enzymes to digest carbohydrates and proteins., So, food P and Q has carbohydrates and, proteins in them, therefore, they both would be, partly digested in the stomach., 13. Rings of cartilage are present in the throat to, ensure that the air passage does not collapse., 14. Inside the food vacuole, complex food breaks, down into small molecules and get readily, absorbed by the cytoplasm. The undigested, food material is removed by the cell, membrane, which ruptures suddenly at any, place and eliminates out the undigested food,, i.e. egestion., , 16. The correct labelling is, A = Bowman’s capsule, B = Tubular part of nephron, C = Glomerulus, D = Collecting duct, Nephrons has a cup-like capsule called, Bowman’s capsule, at its upper end and the, lower end is tube-like and called tubule. Blood, , sin i, sin r, , Since, slope angle (q) of given graph > 45°, So, refractive index (m ) < 1, , æ, 1 ö, ÷, çQm =, slope ø, è, , \The light is travelling from denser to rarer, medium and speed of light in medium I is less, than the speed of light in medium II., 20. Given, u =, , -f, 2, , Using lens formula,, 1 1 1, = +, v u f, Þ, , 1, 1, 1, =, +, v - f, f, 2, =, , or, , -2 + 1, 1, =f, f, , v=- f, , 21. The path of light on entering the glass prism is, shown below, , Incident ray, , Emergent, ray, , Here, both the incident ray and emergent ray, bend towards the base of the glass prism at, both the faces., , SAMPLE PAPER 2, , 15. When we breathe in, then, (i) the muscles between the ribs contracts, causing the ribcage to move upward and, outward, and, (ii) the diaphragm contracts and moves, downward. The upward and outward, movement of ribcage, as well as, downward movement of diaphragm, both, increase the space in the chest cavity and, make it larger., , m=

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98, , CBSE Sample Paper Science Class X (Term I), , In test tube (C), nitric oxide is evolved., , 22. The path of light is shown below :, Incident ray, 40º, , In test tube (D), nitric oxide is evolved., , Refracted, ray, , 40°, Emergent, ray, , 3Cu + 8HNO 3 ¾® 3Cu(NO 3 )2 + 2NO + 4H 2O, (Copper) (Dil. nitric, (Copper nitrate) (Nitric (Water), oxide), oxide), 3Mg + 8HNO 3 ¾®, (Magnesium) (Dil. nitric, oxide), , 3Mg(NO 3 )2, (Magnesium, nitrate), , Glass of window pane, , + 2NO + 4H 2O, (Nitric, oxide), , In glass slab incident angle is equal to, emergent angle. Hence, emergent ray is, parallel to incident ray., , (Water), , Hence, only option (b) is incorrect., 28. In (I), the electronic configuration of A is 2 , 1, , 23. Concave mirror produces virtual and enlarged, image only when the object is placed between, pole and focus. So, the distance of tooth from, the mirror should be less than 2.5 cm than the, focal length., , and B is 2, 6., \ The valency of A is 1 and B is 2., , 24. The image is formation of given figure as, shown below, , The formula of compound is A2 B., In II, the electronic configuration of B is 2,6 and, C is 2,7., , A, , B, , 1, , 2, , \ The valency of B is 2 and C is 1., 2f2, , f1 O, , f1, , 2f2, , Image will be formed at focus on the same side, of lens as object. It is virtual, erect and highly, diminished., 25. The oxidation of glucose is exothermic process, because, it involves evolution of heat., C6H12O6 +, Glucose, , O2, , (Oxygen), , ¾¾®, , + H2O, , CO2, , (Carbon dioxide) (Water), , + Heat ¾®, , H2CO3, (Carbonic acid), , SAMPLE PAPER 2, , H 2CO 3 is a weak acid and it is called carbonic, acid. Hence, option (c) is correct., 26. In the given graph, the pH value touched, lowest in 2016 and highest in 2020. However,, higher the pH value, lesser is the concentration, of H+ ions. Hence, highest concentration of H+, ions is present in 2016, whereas pH value is the, lowest., 27. In test tube (A), nitrous oxide is evolved., Zn + 4HNO 3 ¾® Zn(NO 3 )2 + 2N 2O + 2H 2O, , (Zinc), , (Dil. nitric, acid), , (Zinc nitrate), , (Nitrous, oxide), , Water, , In test tube (B), nitric oxide is evolved., 3Ag + 4HNO 3 ¾® 3AgNO 3 + NO + 2H 2O, (Silver), , (Dil. nitric, acid), , (Silver nitrate), , (Nitric, oxide), , Water, , B, , C, , 2, , 1, , The correct formula of compound is BC2., In (III), the electronic configuration of C is 2,7, and D is 2, 8, 3., \ The valency of C is 1 and D is 3., C, , D, , 1, , 3, , The formula of compound is C3 D., In (IV), the electronic configuration of E is 2, 8,, 6 and F is 2, 8, 8, 2., The valency of E and F is 2 and 2 respectively., E, , F, , 2, , 2, , The correct formula of compound is EF., Hence, (II) and (IV) are wrongly formed., 29. Among the given statements related to NaCl,, only (I) statement is wrong, because sodium, hydroxide (NaOH) is prepared by chlor-alkali, process, but not NaCl salt., 30. In test tube A, the solution has pH = 2 (acidic)., Hence, on adding universal indicator, it shows, red colour which is correct. In test tube B, the, solution has pH = 10 (basic). Hence, on adding, universal indicator, it should show dark blue, colour instead of green colour.

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99, , CBSE Sample Paper Science Class X (Term I), , In test tube C, the solution has pH = 9 (basic)., Hence, on adding universal indicator, it shows, blue colour which is correct. In test tube D, the, solution has pH = 7 (neutral). Hence, on, adding universal indicator, it should show, green colour instead of violet colour., 31. Both A and R are correct and R is the correct, explanation of A. Plaster of Paris is used for, setting fractured bones because when plaster, of paris is mixed with water, it forms hard, material, known as gypsum, which is used and, applied around the fractured limbs., 32. A is true but R is false because refrigeration of, cooked food at low temperature is done to, prevent the growth of microorganisms, activity, of enzymes and purely chemical reactions., 33. A is false, but R is true., All the veins carry deoxygenated blood from, various organs to the heart except pulmonary, veins, which carry oxygenated blood from the, lungs to the heart., 34. A is true but R is false., In diffused reflection, a parallel beam of, incident light is reflected in different, directions. The laws of reflection are valid at, each and every point of surface either it is, smooth or rough. The diffused reflection is due, to the roughness of surface., 35. (d) In (I) reaction, Na 2CO 3 reacts with HCl and, evolves CO 2 gas., Na 2CO 3 + HCl ¾® NaCl + H 2O + CO 2, In (II) reaction, ZnO reacts with HCl, but does not evolve CO 2 gas., ZnO + HCl ¾® ZnCl 2 + H 2O, In (III) reaction, KOH does not reacts with HCl, and does not evolveCO 2 gas, which is incorrect., The possible reaction of KOH and HCl is :, KOH + HCl ¾® KCl + H 2O, This reaction does not evolve CO 2, , AgNO 3 + HCl ¾® AgCl + HNO 3, Hence, option (d) is correct., 36. Bile does not contain any enzyme, instead it, has bile salts. Bile emulsifies fat into smaller, droplet., Saliva has salivary amylase enzyme, gastric, juice has pepsin enzyme and pancreatic juice, has trypsin, amylase and lipase enzymes., , 38. Trypsin is an enzyme that catalyses the, digestion of proteins in the small intestine., So, if trypsin is lacking in the pancreatic juices,, the digestion of proteins in the small intestine, will not takes place properly., 39. Given, object distance, u = - 25 cm, Focal length, f = - 25 cm, From lens formula,, , Þ, , 1 1 1, - =, v u f, 1, 1, 1, =, +, v -25 ( -25 ), 1, 2, =v, 25, , Þ, Þ, , v=-, , 25, = - 12 .5 cm, 2, , Nature of image is virtual, erect and, diminished., 40. Given, power of convex lens, P1 = 8 D, Power of concave lens, P2 = - 10 D, \Power of combination, P = P1 + P2, = 8 D + ( -10 D), Þ, , P = -2 D, , 41. The three main proteolytic enzymes produced, naturally in your digestive system are pepsin,, trypsin and chymotrypsin., Pepsin is a stomach enzyme that aids in the, digestion of protein in food. It breaks down the, protein in food into polypeptides., The pancreas secretes pancreatic juice which, contains enzymes like trypsin for digesting, proteins., Chymotrypsin plays a significant role in, breakdown of partially hydrolysed proteins, into peptides when activated., 42. The main function of loop of Henle is, absorption of water. Therefore, if Henle’s loop, was absent from mammalian nephron, the, urine will be more dilute., 43. Given, refractive index of dense flint glass,, m g = 1.65, Refractive index of alcohol, m a = 1.36, , SAMPLE PAPER 2, , In (IV) reaction, AgNO 3 reacts with HCl but, does not evolve CO 2., , 37. The germinating seed undergo aerobic, respiration as oxygen is available., The reaction is, C6H12O6 + 6 O2 ¾® 6 CO2 + 6 H2O + energy.

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100, , CBSE Sample Paper Science Class X (Term I), , 44., , Now, refractive index of dense flint glass w.r.t., alcohol is, m g 1.65, a, =, = 1.21, mg =, m a 1.36, , So, angle of deviation and angle of prism is not, equal to angle of incidence., [Q Ðe ¹ 0 ], Similarly, Ðe + ÐD ¹ Ði, , Glass, , 60º, , Emergent, ray, , We know that, incident ray and emergent ray, are parallel to each other in rectangular glass, slab. Therefore,, (corresponding angles), , Þ Ðe = 60°, 45. Wire at point C is at centre of curvature of, concave lens, so its image C ¢ will be at C, i.e., C = C¢, , 48. The elements B, C and D were discarded for, usage by the company because for making, jewellery, the element should be malleable,, ductile, lustrous and should have high melting, point. So, these properties were only seen in, elements A. So, rest of others were discarded., 49. As acetic acid is acidic in nature, it changes, blue litmus paper into red., 50. Acetic acid gives a pungent smell of vinegar., 51. When acetic acid is added in sodium, bicarbonate solution, sodium acetate is formed, along with evolution of carbon dioxide gas and, water., CH 3COOH( aq) + NaHCO 3( s) ¾®, , Now, for point D;, , CH 3COONa( aq) + CO 2( g ) ­ + H 2O ( l ), , Given, u = 10 + 10 + 1 = - 21 cm,, f = - 10 cm, By mirror formula,, 1 1 1, + =, v u f, Þ, , 1 1 1, 1, 1 ö, = - =, - æç, ÷, v, f u -10 è -21 ø, , Þ, , v=, , -210, 11, , 210, from mirror., 11, The length of image of side CD is C ¢ D¢ or CD¢, 210, 210, =- ( -20 ) = 20 11, 11, 10, = cm, 11, Image of point D, i.e. D¢ is at -, , SAMPLE PAPER 2, , [Q ÐA ¹ 0 ], , When a ray of light is travelling through a, prism and refracted ray is parallel to the base,, this condition gives the minimum angle of, deviation., , Incident ray 60º, , Ði = Ðe, , ÐD = Ði + Ðe - ÐA, , 46. To get an erect image from a concave mirror,, the object should be placed between pole and, the focus of mirror. So, among given options, only 10 cm is less than the focal length of, mirror., 47. Angle of deviation depends upon angle of, prism ( ÐA), angle of incidence ( Ði ) and angle, of emergence ( Ðe) by relation, , 52. On passing excess of CO 2 in limewater, the, milkiness disappears due to formation of, calcium carbonate., Ca(OH)2( aq) + CO 2( g ) ¾® CaCO 3 ( s) ¯ + H 2O ( l ), Calcium, hydroxide, (limewater), , Carbon, dioxide, , Calcium, carbonate, , Water, , 53. When air is blown from mouth into test tube,, the limewater turns milky because the air we, breathe out has more CO2., 54. When CO 2 gas is passed through limewater, it, turns milky due to the formation of calcium, carbonate., 55. In test tube-1 : Limewater turns milky after a, long time because the amount of carbon, dioxide present in atmospheric air is very less, as compared to exhaled air., In test tube-2 : Limewater turns milky, immediately as the exhaled air is rich in carbon, dioxide., 56. Statement (iii) and (iv) are correct. The air, exhaled through mouth turns lime water milky, at very fast rate because exhaled air contains, more CO 2 as compared to atmospheric air.

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101, , CBSE Sample Paper Science Class X (Term I), , 57. When object is placed at the centre of, curvature of concave mirror, the image formed, is of same size as that of object, real and, inverted., 58. A convex mirror forms a large number of, images which are very close to each other, so, they can be seen on mirror and it gives a wider, field of view as shown., Convex mirror, , 59. As the image of head is of same size, so upper, portion of mirror is plane., The middle portion image is smaller, so, the middle portion of mirror is convex and the, image of legs is bigger than original, so the, lower portion of mirror is concave., 60. To get a large image of object, concave mirror, is used., When object is placed between focus and pole,, it forms an enlarged virtual image of object., But convex mirror only forms diminished, image., , Larger field view, , SAMPLE PAPER 2

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SAMPLE PAPER 3, SCIENCE, A Highly Simulated Practice Questions Paper, for CBSE Class X (Term I) Examination, , Instructions, (i) This paper is divided into three Sections:, (a) Section A – Contains 24 questions. Attempt any 20 questions., (b) Section B – Contains 24 questions. Attempt any 20 questions., (c) Section C – Contains 12 questions. Attempt any 10 questions., (ii) Each questions carries 0.80 mark., (iii) There is NO negative marking., Maximum Marks : 40, Time allowed : 90 Min., , Roll No., , Section A, Section-A consists of 24 questions. Attempt any 20 questions from this section. The first attempted 20, questions would be evaluated., , 1. Anil took 3 mL of sodium sulphate solution in a test tube and added 3 mL of barium, chloride solution. What would he observe?, (a) The solution turned red, (b) White precipitation was formed, (c) Yellow precipitation was formed, (d) The reaction mixture became hot, , 2. Identify the gas A in the following experiment., Gas A, Boiling tube, , Sodium hydrogen, carbonate, Burner, , (a) H 2, , (b) CO 2, , (c) O 2, , (d) H 2 S

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103, , CBSE Sample Paper Science Class X (Term I), , 3., , Metal, H2O, , Gas, , Metal oxide, , Which of the following two combinations are correct ?, Metal, , Gas evolved, , (i), , Al, , Yes, , (ii), , Fe, , Yes, , (iii) Cu, , No, , (iv) Ca, , No, , (a) (i) and (ii), (c) (i), (ii) and (iii), , (b) (ii) and (iii), (d) Only (iv), , 4. Which of the following correctly represents a balanced chemical equation?, (a) MgO ( s) + HNO 3 ( aq) ¾® Mg(NO 3 ) ( aq) + H 2 O( l), (b) MgO ( s) + 2HNO 3 ( aq) ¾® Mg(NO 3 ) 2 ( aq) + H 2 O( l), (c) 2MgO ( s) + 2HNO 3 ( aq) ¾® 2Mg(NO 3 ) 2 ( aq) + H 2 O( l), (d) 2MgO ( s) + 4HNO 3 ( aq) ¾® 2Mg(NO 3 ) 2 ( aq) + 3H 2 O( l), , 5. The graph has shown three pH curves A, B and C., , pH value, , A, 7, , C, B, , 0, Volume of solution, , Which letter represents the addition of acid to solution?, (b) B, (d) Both A and C, , (a) A, (c) C, , 6. In the reaction of ammonia with oxygen,, , 7. The chemical reaction between copper oxide and hydrogen can be categoriesed as, (a) neutralisation reaction, (c) combination reaction, , (b) decomposition reaction, (d) redox reaction, , SAMPLE PAPER 3, , 4NH 3 + 5O 2 ¾® 4NO + 6H 2 O, Which option in the given table correctly represents the substance oxidised and the, oxidising agent?, Substance oxidised, Oxidising agent, (a), NH 3, O2, (b), O2, NO, (c), NO, NO, (d), H2O, NH 3

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104, , CBSE Sample Paper Science Class X (Term I), , 8. Which of the given options correctly represents the parent acid and base of potassium, nitrate?, Parent acid, (a) Carbonic acid, (b) Nitric acid, (c) Nitric acid, (d) Hydrochloric acid, , Parent base, Potassium hydroxide, Potassium oxide, Potassium hydroxide, Potassium oxide, , 9. Which of the following statement is correct regarding hydrochloric acid and water?, (a) Hydrochloric acid dissociates into hydrogen and hydroxyl ions in the solution, (b) Hydrochloric acid does not ionises in the solution, (c) Hydrochloric acid forms hydronium ions in the solution, (d) Hydrochloric acid in water produces only negative ions and releases hydrogen gas, , 10. Why is it important to keep the food items in refrigerator?, (a) To protect them from rusting, (c) To avoid contact with viruses, , (b) To protect them from rancidity, (d) To protect them form sunlight, , 11. Carefully study the diagram of the human heart with labels (i) to (iv). Select the option, which given correct identification and main function and/or characteristic., (i), , (iv), , (ii), , (iii), , (a) (i) Superior vena cava ® brings deoxygenated blood from lower body parts, (b) (ii) Inferior vena cava ® brings deoxygenated blood from upper body parts, (c) (iii) Septum ® it divides the left and right side of the heart., (d) (iv) Aorta ® carry deoxygenated blood to the body parts, , 12. What are the functions of the xylem?, Carrying sugars, , Carrying water, , Carrying mineral ions, , Giving support, , r, , r, , ü, , (b), , ü, ü, , r, , r, , (c), , r, r, , ü, ü, , r, , (d), , ü, ü, ü, , SAMPLE PAPER 3, , (a), , Key, ü = a function of xylem, r = not a function of xylem., , ü

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105, , CBSE Sample Paper Science Class X (Term I), , 13. Herbivores have longer small intestine because, (a) they need to digest cellulose, (b) they digest proteins and fats, (c) digestive juices in herbivores are not functional, (d) None of the above, , 14. The figure given below shows a diagram of closed and open stomatal pore with labels, (i) to (iii). Identify the correct label with it functions., (i), Nucleus, , (ii), , (iii), , (a) (i) Guard cells – Helps in exchange of water, (b) (ii) Chloroplast – Site for the photosynthesis, (c) (ii) Stomatal pore – Participate in gaseous exchange during photosynthesis, (d) (iii) Epidermal cells – Controls opening and closing of the stomata, , 15. The diagram shows the ribs and some of the muscles used in breathing. Identify the, phase of breathing., Sternum, Vertebrae, Breathing, out, , External, intercostals, Diaphragm, , (a) During inhalation, chest cavity is compressed due to relaxation of ribs and diaphragm, (b) During exhalation, the ribs muscles and diaphragm relaxes, (c) During exhalation, the chest cavity becomes larger due to relaxation of ribs and diaphragm, (d) During inhalation, the diaphragm contracts and ribs muscles relaxes simultaneously, , 16. Observe the diagram of hemodialysis,, (A ), (C ), , Dialysing, solution, , Fresh dialysing, solution, , (D ), , SAMPLE PAPER 3, , (B )

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106, , CBSE Sample Paper Science Class X (Term I), , Match the labelling referred in Column I and correlate it with Column II., Column I, , Column II, , (A), , 1., , It is made up of selectively permeable membrane through which, patient’s blood passes., , (B), , 2., , It is the line from artery to the pump., , (C), , 3., , It contains solution with excess salts and urea., , (D), , 4., , It is the line from the apparatus to vein., , Codes, A, (a) 4, (c) 4, , B, 2, 2, , C, 1, 3, , D, 3, 1, , A, (b) 2, (d) 2, , B, 3, 4, , C, 4, 1, , D, 1, 3, , 17. The part of a lens through which a ray of light passes without suffering any deviation, is called, (a) centre of curvature, (c) focus, , (b) pole, (d) optical centre, , 18. In an experiment to trace the path of a ray of light passing through a glass prism for, different value of angle of incidence, it is observed that the emergent ray, , Prism, , (a) is parallel to the incident ray, (c) is perpendicular to the incident ray, , (b) is parallel to refracted ray, (d) bends at angle to the direction of incident ray, , 19. Which of the following lenses would you prefer to use while reading small letters, found in dictionary?, (a) A convex lens of focal length 50 cm, (b) A concave lens of focal length 30 cm, (c) A convex lens of focal length 5 cm, (d) A concave lens of focal length 5 cm, , SAMPLE PAPER 3, , 20. Consider a light ray travels from medium I to medium II to medium III of refractive, indices 1, 1.23 and 2.12, respectively. Arrange the speed of light through them in, decreasing order., (a) Speed of light in medium I > Speed of light in medium II > Speed of light in medium III, (b) Speed of light in medium III > Speed of light in medium II > Speed of light in medium I, (c) Speed of light in medium I > Speed of light in medium III > Speed of light in medium II, (d) Speed of light in medium III > Speed of light in medium I > Speed of light in medium II, , 21. An object is placed at some distance u from a convex lens of focal length f . If image, obtained is virtual, erect and magnified, then choose the correct relation of image, distance v with u and f (in magnitude)., (a) v < f < u, (b) f < u < v, (c) u < v < f, (d) u < f < v

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107, , CBSE Sample Paper Science Class X (Term I), , 22. A student used a device (X) to obtain/focus the image of a well illuminated distant, building on a screen (S) as shown in the figure. Name the device used and its focal, length., X, S, , 8 cm, ., , (a) Concave lens of focal length - 8 cm, (c) Convex lens of focal length 8 cm, , 23., , (b) Concave mirror of focal length -8 cm, (d) Convex mirror of focal length 8 cm, , Incident ray, 35º, , Plane mirror, , The total angle between the incident ray and reflected ray will be, (a) 35°, (b) 70°, (c) 110°, (d) 55°, , 24. Study the following diagrams in which the path of a ray of light passing through a, glass prism as traced by four students P, Q, R and S as shown, , P, , Q, , Which student traced the path correctly?, (a) Student P, (b) Student Q, , R, , (c) Student R, , S, , (d) Student S, , Section B, Section B consists of 24 questions (Sl. No. 25 to 48). Attempt any 20 questions from this section. The first, attempted 20 questions would be evaluated., , 25. Potassium chlorate ¾® KCl + X, , SAMPLE PAPER 3, , Identify the correct option from the given table which represents the type of reaction, and gas evolved in reaction., Exothermic, Gas evolved, (a), ü, r, (b), r, ü, (c), ü, ü, (d), r, r

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108, , CBSE Sample Paper Science Class X (Term I), , 26. In which year, the maximum acidity of rain was recorded?, , pH, value, Rain pH value, , 2002 2006 2010 2014, , (a) 2002, , (b) 2010, , 2018, , (c) 2018, , (d) 2014, , 27. Zinc pieces were placed in each of the four test tubes containing different salt solutions, as shown below, Aluminium, sulphate, solution, , Zinc, sulphate, solution, , Zinc pieces, , Zinc pieces, I, , II, , Iron, sulphate, solution, , Copper, sulphate, solution, , Zinc pieces, , Zinc pieces, III, , IV, , In III and IV solutions, the change in colour is observed but not in others. What is the, reason for this observation ?, (a) Zinc is more reactive than iron and copper, (b) Zinc is less reactive than iron and copper, (c) Aluminium is less reactive than zinc, iron and copper, (d) Zinc is more reactive than aluminium, , SAMPLE PAPER 3, , 28. The table shown below gives information about four substances A, B, C and D., Substances, , Melting point (K), , Electrical conductivity in aqueous medium, , A, , 298, , Poor, , B, , 1120, , Good, , C, , 1850, , Good, , D, , 935, , Poor, , Identify the substances which are ionic in nature?, (a) A and B, (b) B and C, (c) C and D, , (d) A and C, , 29. A boy was stung by a bee. He started crying because of stung. Then her mother washed, the affected area with soap and he got some relief. Which of the following statements, are correct regarding this incident?, I. Soap is acidic in nature., II. Soap is basic in nature., III. Acid is present in bee sting., IV. Base is present in bee sting., (a) I and III, (b) I and IV, (c) II and III, (d) II and IV

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109, , CBSE Sample Paper Science Class X (Term I), , 30. Which of the following setups is/are most appropriate for the evolution of hydrogen, gas and its identification?, , (a) I and III, , (b) II and IV, , (c) I, II and II, , (d) Only II, , Direction (Q. Nos. 31-34) For given questions two statements are given-one labelled Assertion (A) and, the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d), as given below., (a) Both A and R are true and R is the correct explanation of A., (b) Both A and R are true, but R is not the correct explanation of A., (c) A is true, but R is false., (d) A is false, but R is true., , 31. Assertion Antacids are used to neutralise the effect of extra acid produced in the, stomach during indigestion., Reason Antacids are basic in nature., , 32. Assertion Sodium chloride is used for the manufacturing of many chemicals like, bleaching powder, sodium hydroxide, etc., Reason The main source of common salt is sea water., , 33. Assertion Amylase is the first enzyme to mix with food in digestive tract., Reason It helps in digestion of starch., , 34. Assertion A rainbow is always formed in the sky after a rain shower and in the same, direction as that of sun., Reason Water droplets of rain act like tiny prism., , 35. The table given below shows different types of indicators., Indicators, , Synthetic, , (i) Phenolphthalein, , P, , O, , (ii) Methyl orange, , O, , P, , (iii) Vanilla essence, , P, , O, , (iv) Turmeric, , P, , O, , Which of the following gives correct information regarding the types of indicators?, (a) (i) and (ii), (b) (iii) and (iv), (c) (ii) and (iv), (d) (i), (ii) and (iv), , 36. Among the following choose the correct option which included the organisms that, have a holozoic mode of nutrition., (a) Plasmodium and Amoeba, (c) Parasite and Paramecium, , (b) Amoeba and Paramecium, (d) Plasmodium and Paramecium, , SAMPLE PAPER 3, , Natural

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110, , CBSE Sample Paper Science Class X (Term I), , 37. Choose the correct statement that describes arteries., (a) They have thick elastic walls, blood flows under high pressure; collect blood from, different organs and bring it back to the heart, (b) They have thin walls with valves inside, blood flows under low pressure and carry, blood away from the heart to various organs of the body, (c) They have thick elastic walls, blood flows under low pressure carry blood from the, heart to various organs of the body, (d) They have thick elastic walls without valves inside, blood flows under high pressure, and carry blood away from the heart to different parts of the body., , 38. Which of the following statements accurately describe what happens in the mouth?, (a) Amylase breaks down large proteins molecules into smaller maltose molecules, (b) Chewing increases the surface area of food for digestion, (c) Saliva emulsifies fats into smaller droplets, (d) Teeth absorbs large insoluble molecules, , 39. The magnification produced by a plane mirror is +1. What does it mean?, (a) Image is of same size as that of object and real, (b) Image is inverted and real, (c) Size of image is same as that of object but it is virtual and inverted., (d) Image is erect and virtual and of same size as that of object., , 40. An object at a distance of 25 cm is slowly moved towards the pole of convex mirror., The image will become, (a) shortened and real, (c) enlarged and virtual, , (b) diminished and virtual, (d) enlarged and real, , 41. Which of the following parts of the heart contains oxygenated blood?, (a) Pulmonary veins, left atrium and aorta, (b) Pulmonary artery, right ventricle and vena cava, (c) Pulmonary artery, left atrium and aorta, (d) Right atrium, right ventricle and aorta, , 42. Which of the following is not a purpose of transpiration ?, (a) Supplies water for photosynthesis, (b) Helps in translocation of sugar in plants, (c) Cools leaf surface, (d) Transport minerals from the soil to all the parts of the plant, , SAMPLE PAPER 3, , 43. A person of height 180 cm is standing in front of a plane mirror. His eyes are at a height, of 172 cm from the floor. To see his full image for minimum length of mirror, the lower, end of the mirror should be placed at height of, (a) 90 cm from the floor, (b) 94 cm from the floor, (c) 8 cm from the floor, (d) 86 cm from the floor, , 44., , Red, White, light, , Violet, Prism

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111, , CBSE Sample Paper Science Class X (Term I), , A student observes the above phenomenon in the lab when a white light passes, through a prism. His observations are, I. white light splits into many colours, II. angle of deviation of red is greater than violet colour, III. violet light deviates most., IV. speed of red light is greater than violet light., V. wavelength of violet colour is more than red., Which one of the combination of the above statements given below is correct ?, (a) (I), (II) and (III) are correct, (b) (III) and (V) are correct, (c) (I), (III) and (IV) are correct, (d) (I), (IV) and (V) are correct, , 45., Plane mirror, , Man, , In the above figure, a man of height 5.8 ft is standing in front of a plane mirror. The, minimum size of plane mirror to see his full image is, (a) 2.9 ft, (b) 4 ft, (c) 5.8 ft, (d) 11.6 ft, , 46. The refractive index of diamond is 2.42 and that of glass is 1.52. How much faster does, light travel in glass than in diamond?, (a) 2.42 times faster, (c) 1.52 times faster, , (b) 1.59 times faster, (d) 1.63 times faster, , 47. A circle of radius 10 cm is placed in front of a convex mirror of focal length 10 cm as, shown below, 10 cm, O, P, , If the image is half the size of object, find the radius of image of circle., (a) 10 cm, (b) 1 cm, (c) 5 cm, (d) 2.5 cm, , 48. A utensil manufacturing unit tested few elements on the basis of their physical, properties., A, , B, , C, , D, , Malleable, , Yes, , No, , No, , Yes, , Ductile, , Yes, , No, , No, , Yes, , Heat conductivity, , Yes, , Yes, , Yes, , No, , High, , Low, , Low, , High, , Melting point, , Which of the above elements were not approved for usage by the company?, (a) A, B and D, (c) B, C and D, , (b) A, B and C, (d) A, B and D, , SAMPLE PAPER 3, , Properties

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112, , CBSE Sample Paper Science Class X (Term I), , Section C, This Section C consists of three Cases followed by questions. There are a total of 12 questions in this, section. Attempt any 10 questions from this section. The first attempted 10 questions would be evaluated., Case I. 2 mL of ethanoic acid was taken in test tube I and test tube II. A red litmus paper was, introduced in test tube I and a pH paper was introduced in test tube II. The experiment was, performed by four students A, B, C and D; and they reported their observation as given in the table., , Students Action on red litmus paper, , Action on pH paper, , A, , Turned blue, , Turned pink, , B, , Remains unchanged, , Turned green, , C, , Turned blue, , Turned blue, , D, , Remains unchanged, , Turned pink, , 49. Which set of observation is correct?, (a) A, , (b) B, , (c) C, , (d) D, , 50. What is the approximate pH of ethanoic acid?, (a) 4, , (b) 2, , (c) 6, , (d) 0, , 51. What will be the effect on phenolphthalein in ethanoic acid?, (a) Pink, , (b) Red, , (c) Yellow, , (d) Colourless, , 52. The dark blue colour on pH paper indicates that the sample is, (a) highly basic, , (b) highly acidic, , (c) mild basic, , (d) mild acidic, , Case II. The figure shown below represents the flow of blood in the human heart. The blood passes, through the heart two times to supply once to the whole body. So, it is called double circulation of blood., , SAMPLE PAPER 3, , 53. In humans, right auricle receives deoxygenated blood from, (a) aorta, (c) pulmonary vein, , (b) vena cava, (d) pulmonary artery, , 54. The pulmonary arteries arises from the, (a) right auricle, , (b) left ventricle, , (c) right ventricle, , (d) left auricle, , 55. What is the correct route for blood flow in human?, (a) Left atrium ® Left ventricle ® Lungs ® Right ventricle ® Right atrium, (b) Left atrium ® Left ventricle ® Right ventricle ® Right atrium ® Lungs, (c) Right atrium ® Right ventricle ® Left ventricle ® Left atrium ® Lungs, (d) Right atrium ® Right ventricle ® Lungs ® Left atrium ® Left ventricle

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113, , CBSE Sample Paper Science Class X (Term I), , 56. In mammals, veins differ from arteries in having, 1. Low pressure, , 2. Thicker walls, , 3. Internal valves, (a) 1 and 3, (c) 3 and 4, , 4. High pressure, (b) 1 and 2, (d) 2 and 3, , Case III. An Overhead Projector (OHP), like a film or slide projector, uses light to project an enlarged, image on a screen. In an OHP, the source of the image is a page-sized sheet of transparent plastic film, (also known as foils) with the image to be projected either printed or hand-written/drawn., These are placed on the glass surface of the projector, which has a light source below it and a projecting, mirror and lens assembly above it as shown below. They are widely used in education and business. It, works on the same principle as a slide projector, in which a focussing lens projects light from an, illuminated slide onto a projector screen, where a real image is formed., Screen, Plane, mirror, , Image, , Focal, lens, , Object, , Concave, mirror, , 57. What kind of lens is used to make the overhead projector?, (a) Convex lens, (c) Bifocal lens, , (b) Concave lens, (d) Flat lens, , 58. How the image obtained will be real and erect?, (a) When it passes through the lens and directly obtained on the screen., (b) When it passes through the lens and gets reflected on the mirror to be obtained on the, screen., (c) The screen used, automatically makes the image erect and real., (d) Both (b) and (c), , 59. A concave mirror is used here in place of convex mirror. Why?, , 60. The power of convex lens is ............. and that of concave lens is ....... ., (a) positive, negative, (c) negative, negative, , (b) negative, positive, (d) positive, positive, , SAMPLE PAPER 3, , (a) Concave mirror gives real image, (b) Convex mirror gives real image, (c) Concave mirror gives virtual image, (d) Convex mirror gives virtual image

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OMR SHEET, , SP 3, , Roll No., Sub Code., , Student Name, , Instructions, Use black or blue ball point pens and avoid Gel & Fountain pens for filling the OMR sheet., Darken the bubbles completely. Don’t put a tick mark or a cross mark, half-filled or over-filled bubbles will not be read, by the software., Correct, , ✔, , ✗, , Incorrect, , Incorrect, , Incorrect, , Do not write anything on the OMR Sheet., Multiple markings are invalid., , 1, , 21, , 41, , 2, , 22, , 42, , 3, , 23, , 43, , 4, , 24, , 44, , 5, , 25, , 45, , 6, , 26, , 46, , 7, , 27, , 47, , 8, , 28, , 48, , 9, , 29, , 49, , 10, , 30, , 50, , 11, , 31, , 51, , 12, , 32, , 52, , 13, , 33, , 53, , 14, , 34, , 54, , 15, , 35, , 55, , 16, , 36, , 56, , 17, , 37, , 57, , 18, , 38, , 58, , 19, , 39, , 59, , 20, , 40, , 60, , Check Your Performance, Total Questions:, Total Correct Questions:, , If Your Score is, , Score Percentage =, , Total Correct Questions, Total Questions, , × 100, , Less than 60%, > Average (Revise the concepts again), Greater than 60% but less than 75% > Good (Do more practice), Above 75%, > Excellent (Keep it on)

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115, , CBSE Sample Paper Science Class X (Term I), , Answers, 1. (b), 11. (c), 21. (d), , 2. (b), 12. (d), 22. (c), , 3. (c), 13. (a), 23. (c), , 4. (b), 14. (c), 24. (b), , 5. (b), 15. (b), 25. (b), , 6. (a), 16. (d), 26. (d), , 7. (d), 17. (d), 27. (a), , 8. (c), 18. (d), 28. (b), , 9. (c), 19. (c), 29. (c), , 10. (b), 20. (a), 30. (d), , 31. (a), 41. (a), 51. (d), , 32. (b), 42. (b), 52. (a), , 33. (b), 43. (d), 53. (b), , 34. (d), 44. (c), 54. (c), , 35. (c), 45. (a), 55. (d), , 36. (b), 46. (b), 56. (a), , 37. (d), 47. (c), 57. (a), , 38. (b), 48. (c), 58. (b), , 39. (d), 49. (d), 59. (a), , 40. (b), 50. (a), 60. (a), , EXPLANATIONS, 1. The reaction between sodium sulphate, solution and barium chloride solution, produces white coloured precipitate of barium, sulphate along with sodium chloride solution., Na2SO4 ( aq) + BaCl2( aq) ¾® 2NaCl( aq), Sodium sulphate, , Barium, chloride, , Sodium chloride, , +, , BaSO4 ¯, Barium sulphate, (white ppt.), , 2. When sodium hydrogen carbonate is heated in, a test tube then carbon dioxide is evolved. The, other products are sodium carbonate and, water., D, , 2NaHCO3 ¾® Na2CO3 + H2O + CO2 ­, Sodium hydrogen, carbonate, , Sodium, carbonate, , Water, , Carbon, dioxide, (A), , Hence, gas A is carbon dioxide (CO 2)., , 6. In a given reaction, NH 3 is oxidised to NO by, addition of oxygen or removal of hydrogen, and O 2 itself gets reduced, hence, it is an, oxidising agent. So, option (a) is correct., 7. The reaction between copper oxide and, hydrogen is given below :, CuO ( s) + H2 ( g ) ¾® H2O ( l ) + Cu ( s), Copper, oxide, , (i) 2Al ( s) + 3H 2O ( l ) ¾® Al 2O 3( s) + 3H 2( g ), (ii) 3Fe ( s) + 4H 2O ( l ) ¾® Fe 3O 4 ( s) + 4H 2( g ), (iii) Cu ( s) + H 2O ( l ) ¾® No reaction, (iv) Ca ( s) + 2H 2O ( l ) ¾® Ca(OH) 2( aq) + H 2( g ), So, from these four reactions, only (iv), combination is incorrect., Hence, option (c) is correct., , + H 2 O( l), The total number of atoms of each element are, equal on both sides of the equation., 5. According to the graph, there are three curves,, which are A, B and C, which represent base,, acid and neutral solution respectively, according to their pH value. As base (A) has, pH > 7, acid (B) has pH < 7 and neutral (C) has, pH = 7. Hence, option (b) is correct., , Copper, , 8. Potassium nitrate (KNO 3) salt is formed by, reaction between potassium hydroxide (parent, base) and nitric acid (parent acid)., HNO3 ( aq) + KOH( aq) ¾® KNO3 ( aq) + H2O( l ), Potassium, hydroxide, , Potassium, nitrate, , water, , 9. When hydrochloric acid is treated with water,, then ionisation takes place and hydronium, ions and chloride ions are formed., HCl( aq ) + H2O( l ) ¾® H3O+( aq) + Cl - ( aq), Hydrochloric, acid, , Water, , Hydronium, ion, , Chloride, ion, , 10. The food items which contains fats and oils get, oxidised which results in change of small and, taste in them. This process of slow oxidation of, oil and fat is known as rancidity to prevent, food spoilage and rancidity. That’s why they, are kept in refrigerator to slow down the rate, of oxidation and hence, they can be fresh for, longer time period., 11. The septum is the dividing wall between the, right and left side of the heart. Interauricular, septum seprates right and left atrium and, interventricular septum seprates right and left, ventricle., 12. Xylem is a conducting tissue in plants. It helps, in the transportation of water and minerals, from roots to all parts of the plant., , SAMPLE PAPER 3, , 4. The chemical reaction in option (b) is balanced, MgO ( s) + 2HNO 3( aq) ¾® Mg(NO 3) 2( aq), , Water, , It is a redox reaction because CuO is reduced, to Cu and H 2 is oxidised to H 2O in this, reaction. Both oxidation and reduction occurs, in this reaction. So, it is a redox reaction., , Nitric, acid, , 3. Aluminium, iron and calcium react with water, to produce hydrogen gas while copper does, not react with water., , Hydrogen

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116, , CBSE Sample Paper Science Class X (Term I), , Apart of conducting water and minerals, it also, acts as supportive tissue., 13. Herbivores consume plant and grass based, food which contain cellulose. Digestion of, cellulose takes a longer time. Hence, they need, a longer small intestine to allow complete, digestion of cellulose., 14. (ii) Stomatal pores participate in gaseous, exchange during photosynthesis and also, responsible for large amount of water loss., Incorrect options can be corrected as, , 20. Refractive index of medium I, m I = 1, Refractive index of medium II, m II = 1.23, Refractive index of medium III, m III = 2.12, Speed of light in medium, 1, µ, Refractive index of medium, \, , vI > vII > vIII, , 21. Convex lens forms a virtual, erect and, magnified image only when the object is, placed between lens and focus as shown., A', , (i) Guard cell-helps in exchange of gases., (iii) Chloroplast-site for photosynthesis., 15. When we breathe out, the muscles between the, ribs relax causing the ribcage to move, downward and inward and the diaphragm, relaxes and moves upward. As chest cavity, becomes smaller, air is pushed out from the, lungs., , A, B' F B, , F, , u, f, v, , \, , u < f < v (in magnitude), , 22. Device X is a convex lens of focal length 8 cm., As the rays coming from a distant building, through a convex lens converge at its focus., , 16. The correct labelling is, (A) Line from artery to pump, (B) It is line from apparatus to vein., (C) It is tube made up of a selectively, permeable membrane. The patient’s blood, is passed through these tubes., , 23. The situation is shown below, N, , (D) It is used dialysing solution which contains, urea and excess salts., 17. When a ray of light passes through optical, centre of the lens (both concave and convex), it, will emerge out undeviated (as shown in figure), , F1, , O, , F2, , SAMPLE PAPER 3, , Convex lens, , F1, , O, , F2, , Concave lens, , 18. The light ray while passing through a glass, prism suffers refraction at the two faces of, prism. So, the emergent ray will bend at an, angle to the direction of incident ray., 19. Convex lens is used as magnifying glass., 1, As, focal length,, f =, P, Convex lens of focal length 50 cm has power, 2 D, whereas convex lens of focal length 5 cm, has power 20 D. Hence, for better performance,, its focal length should be small., , 55°, M, , 55°, , 35°, , 35°, , M¢, , O, , From figure, Ði = Ðr = 55 °, \ Ði + Ðr = 55 ° + 55 ° = 110 °, 24. Student Q has traced the path correctly., When a ray of light travels from a rarer (air) to, a denser medium of prism, it bends towards, the normal to the first surface and when a, ray of light travels from a denser medium of, prism to rarer medium (air), it bends away, from the normal to the second surface., 25. When potassium chlorate is heated,, it decomposes to give potassium chloride and, oxygen., D, , 2KClO3( s) ¾® 2KCl( s ) + 3O2( g ), Potassium, chlorate, , Potassium, chloride, , Oxygen, , So, potassium chlorate is heated to form, potassium chloride which is an endothermic, reaction and oxygen gas is evolved. Hence,, option (b) is correct.

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117, , CBSE Sample Paper Science Class X (Term I), , 26. Lower the pH value, higher the acidity of, solution. So, in 2014, the pH value was the, lowest, hence, the maximum acidity of rain, was recorded in 2014., 27. In III and IV solutions, the change in colour is, observed due to displacement reaction because, Zn is more reactive than iron and copper, according to reactivity series., So, Zn displaces iron and copper from their, respective salt solutions and form zinc, sulphate solutions., i.e., , Zn ( s) + FeSO4( aq) ¾® ZnSO4( aq) + Fe( s), , Zn ( s) + CuSO4( aq) ¾® ZnSO4( aq) + Cu( s), On the other hand, aluminium is more reactive, than zinc, hence, it is not displaced by zinc and, therefore, no change in solution is observed in, solution I., Zinc does not react with its own sulphate, solution so, no colour change is observed in, solution II., 28. Ionic compounds are crystalline solids and, hard in nature. Hence, they have high melting, point and they can conduct electricity in, aqueous medium. Therefore , substances B and, C are ionic in nature., 29. Both II and III statements are correct. When, bee stings, it injects formic acid into the skin, that causes pain and irritation. When soap, solution is used on the affected area, it gives, relief because soap solution is basic in nature., Acid + Base ® Salt + Water, This process is known as neutralisation reaction., So, the formic acid which cause pain and, irritation gets neutralised by base present in, soap solution. Hence, gives relief., 30. Set up II is the most appropiate for evolution, of hydrogen gas and its identification., Zn ( s) + 2NaOH( aq) ¾® Na 2ZnO 2(aq) + H 2­( g ), To test the evolution of hydrogen gas properly,, delivery tube should not dip in the solution., , Antacids are basic in nature, therefore they are, used to neutralise the acidity produced in, stomach due to indigestion., 32. Both A and R are true but R is not the correct, explanation of A., Sodium chloride is used in the preparation of, many chemicals because its processing method, is cheap and can be produced in large quantity., , 34. A is false and R is true., A rainbow is always formed in the opposite, direction of the sun. The water droplets act like, small prism. Due to the dispersion of light and, internal reflection, different colours reach the, observer’s eye., 35. Phenolphthalein, methyl orange and vanilla, essence are made in laboratories. Therefore,, they are known as synthetic indicators. But, turmeric is present in nature, hence, it is natural, indicator., Therefore, option (c) shows correct information., 36. Amoeba and Paramecium are unicellular, organism with holozoic mode of nutrition. In, Amoeba food is engulfed with the help of, pseudopodia while in paramecium food is, engulfed with the help of hair-like cilia., 37. Arteries are the vessels which carry blood, away from the heart to various organs of the, body. Since, the blood emerges from the heart, under high pressure, the arteries have thick,, elastic walls. Veins collect the blood from, different organs and bring it back to the heart., They do not need thick walls because the, blood is no longer under pressure, instead they, have valves that ensures that the blood flows, in only one direction., 38. Chewing increases the surface area of food., Large food particles are broken down into, small particles by chewing with the help of, teeth. Salivary amylase breaks down large, starch molecules into smaller maltose, molecules. Bile emulsifies fats into smaller, droplets., 39. If magnification is +1, then it means, h, m= i =1, ho, Þ, hi = ho, The image size is same as that of object size,, since the magnification is positive, the image is, erect and virtual., 40. A convex mirror always forms a diminished, and virtual image of object placed at any, position on principal axis., , SAMPLE PAPER 3, , 31. Both A and R are true and R is the correct, explanation of A., , 33. Both A and R are true, but R is not the correct, explanation for A., Food digestion process begins in the mouth., Mouth contains salivary glands that secrete, saliva which contain salivary amylase enzyme., This enzyme breaks down the starch into, simple sugars.

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118, , CBSE Sample Paper Science Class X (Term I), , 41. Pulmonary veins carry oxygenated blood from, lungs to the heart. Left atrium and left, ventricle contain oxygenated blood., Aorta carries oxygenated blood from heart to, different body organs/parts., 42. Absorption of water and minerals by plants, directly depends on the transpiration pull, generated by loss of water through stomata,, but translocation of sugar is a physiological, process and is not related to transpiration loss, of water., 43. The minimum length of mirror for full image,, 180, = 90 cm, 2, \The lower end of the mirror should be at, (180 - 172 ) ù, x = 180 - é90 +, úû, êë, 2, l=, , = 180 - (90 + 4 ), = 86 cm from the floor, 44. Splitting of white light into different colours is, called dispersion. The colour violet has a, smaller wavelength, so it deviates most while, red colour deviates least due to its longer, wavelength. As, the angle of deviation of red is, least, so the speed of red colour is most., 45. To see the full image of man, the size of mirror, required is half the height of man, i.e., H 5.8, \, = 2.9 ft, l=, =, 2, 2, 46. Given, m g = 1.52 , m d = 2.42, As,, \, , vg, vd, vg, vd, , =, , md, mg, , =, , 2.42, = 1.59, 1.52, , æQm µ 1 ö, ç, ÷, vø, è, , 1, m = , ho = 2r = 20 cm, 2, 1 h, h, \ Magnification, m = i Þ = i, 2 20, ho, , SAMPLE PAPER 3, , 47. Given,, , hi = 10 cm, h 10, \ Radius of image = i =, = 5 cm, 2, 2, or, , 48. The elements B, C and D were not approved by, company for usage because for utensil, manufacturing because for usage of an, element, it should be malleable, ductile, good, conductor of heat and have high melting point., A has all these properties., Hence, A was approved and rest were, disapproved., , 49. Only D student observed the correct, information because red litmus paper remains, unchanged in ethanoic acid, while pH paper, turns pink in acidic solution., 50. The approximate pH of ethanoic acid is 4 as, the pH paper shows pink colour on its addition., 51. Phenolphthalein becomes colourless in, ethanoic acid because it turns colourless in, acidic medium and gives pink colour in, alkaline medium., 52. pH paper gives dark shades of blue in alkaline, or basic medium. Hence, if any sample shows, dark blue colour on pH paper, it means it is, highly basic in nature., 53. In human, right auricle receives deoxygenated, blood from vena cava. The superior vena cava, and inferior vena cava carries deoxygenated, blood from different body parts to the heart., 54. The pulmonary arteries arises from the right, ventricle and carry deoxygenated blood to the, lungs for oxygenation., 55. The deoxygenated blood enters the right, atrium through the vena cava. This blood, passes to the right ventricle and through the, pulmonary artery this deoxygenated blood is, pumped into lungs for oxygenation. Then, the, oxygenated blood is transported to left atrium, through the pulmonary veins and then moves, to the left ventricle from where it is pumped, into the whole body through aorta., 56. Veins are the blood vessels present throughout, the body. They carry deoxygenated blood from, the heart to the body. The blood pressure in, arteries in much greater than that in the veins., The valves are present in veins to prevent, back flow of blood., 57. Convex lens is used here to focus the beam of, light., 58. The image when passed through the lens is, inverted and then it gets reflected by the plane, mirror. So, the erect and real image is obtained, on screen., 59. Concave mirror is used here because it can, give real image, while convex mirror gives, virtual image., 60. The focal length of convex lens is positive, so, its power is positive. Similarly, focal length of, concave lens is negative and its power is also, negative.

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P, , SAMPLE PAPER 4, SCIENCE, A Highly Simulated Practice Questions Paper, for CBSE Class X (Term I) Examination, , Instructions, (i) This paper is divided into three Sections:, (a) Section A – Contains 24 questions. Attempt any 20 questions., (b) Section B – Contains 24 questions. Attempt any 20 questions., (c) Section C – Contains 12 questions. Attempt any 10 questions., (ii) Each questions carries 0.80 mark., (iii) There is NO negative marking., Maximum Marks : 40, Time allowed : 90 Min., , Roll No., , Section A, Section-A consists of 24 questions. Attempt any 20 questions from this section. The first attempted 20, questions would be evaluated., , 1. Aman took an iron nail and immersed it in copper sulphate solution, for few minutes., What would he observe?, (a) The surface of iron nails acquire black coating, (b) The colour of solution changes to green, (c) The colour of solution fades away, (d) No reaction takes place, , 2. Identify the gas evolved in the following experiment., Stand, Burning matchstick, Capillary tube, Cork, Clamp, HCl (dil.), Solid particles of Zn, Burner, , (a) H 2, (c) O 2, , (b) CO 2, (d) Cl 2

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120, , CBSE Sample Paper Science Class X (Term I), , 3., , Metal carbonate, Dil. HCl, , Gas, , Metal salt, , Which of the following two combinations are correct?, , (a) (i) and (ii), , Metal carbonate, , Gas evolved, , (i) Copper, , Yes, , (ii) Silver, , No, , (iii) Zinc, , Yes, , (iv) Sodium, , No, , (b) (ii) and (iii), , (c) (iii) and (iv), , (d) (i) and (iii), , 4. Which of the following correctly represents a balanced chemical equation?, (a) Cu( s) + HNO 3( aq) ¾® Cu(NO 3 ) 2 (aq) + NO 2( g) + H 2 O( l), (b) Cu( s) + 4HNO 3( aq) ¾® Cu(NO 3 ) 2 (aq) + 4NO 2( g) + 2H 2 O( l), (c) Cu( s) + 4HNO 3( aq) ¾® Cu(NO 3 ) 2( aq) + 2 NO 2( g) + 2H 2 O( l), (d) Cu( s) + 3HNO 3 (aq) ¾® Cu(NO 3 ) 2( aq) + NO 2( g) + 2H 2 O(l), , 5. The graph given below have 3 curves which are A, B and C. Which letter represents the, relationship between pH and the concentration of solution?, , pH value, , B, , C, A, Conc. of H+, , (a) A, (c) C, , (b) B, (d) Both A and C, , SAMPLE PAPER 4, , 6. In the reaction of hydrogen sulphide with chlorine,, H 2 S + Cl 2 ¾® S + 2HCl, Which option in the given table correctly represents the substance oxidised and the reducing, agent?, Substance oxidised, Reducing agent, (a) H 2 S, H 2S, (b) HCl, S, (c) Cl 2, HCl, (d) S, H 2S, , 7. The reaction between copper sulphate and hydrogen sulphide can be classified as, (a) displacement reaction, (c) combination reaction, , (b) double displacement reaction, (d) decomposition reaction

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121, , CBSE Sample Paper Science Class X (Term I), , 8. Which of the given option correctly represents the parent acid and base of sodium, acetate ?, Parent acid, (a) HCl, (b) CH 3 COOH, (c) CH 3 COOH, (d) Na 2 CO 3, , Parent base, NaOH, Na 2 O, NaOH, HCl, , 9. While diluting a concentrated acid, how can one protects himself from the heat, generation?, (a) Add acid to water with constant stirring, (b) Add water to acid with constant stirring, (c) Add water to acid followed by base, (d) Add base to acid with constant stirring, , 10. Why there is an importance of chemical equation in chemical reactions?, (a) A chemical equation tells us about the substances involved in a reaction., (b) A chemical equation tells us about the atoms or molecules of the reactants and products, involved in a reaction., (c) A chemical equation gives information about the symbols and formulae of the substances, involved in a reaction., (d) All of the above, , 11. Carefully study the diagram of human digestive system with labels (i), (ii), (iii) and (iv), and choose the incorrect pair., (ii), Oesophagus (food pipe), , Salivary glands, Tongue, , Stomach, Liver, (iii), Diaphragm, , Gall bladder, (stores bile), , (iv), , Rectum, , (i), , Anus, , Human digestive system, , (a) (i) Small intestine – Fat digestion, (b) (ii) Buccal cavity – Starch digestion, (c) (iii) Pancreas – Release pancreatic juice for protein digestion, (d) (iv) Large intestine – Carbohydrate digestion, , SAMPLE PAPER 4, , Bile duct, Appendix

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122, , CBSE Sample Paper Science Class X (Term I), , 12. The diagram given below shows the human excretory system., Kidneys, Ureters, X, , Identify the function of part labelled as X., (a) To excrete urea, (b) To produce urea, (c) To produce urine, (d) To store urine, , 13. Peristaltic movements refers to, (a) contraction and expansion of lungs, (b) contraction and relaxation of heart, (c) contraction and expansion of walls of food pipe, (d) movement of blood throughout the body, , 14. The figure given below shows a human circulatory system with labels (i) and (iv)., Identify the correct labels with its functions and/or characteristics, (iv), (ii), (i), , (iii), , (a) (i) Pulmonary vein ® has low oxygen concentration and high pressure, (b) (ii) pulmonary artery ® has high oxygen concentration and low pressure, (c) (iii) Vena cava ® has high oxygen concentration and high pressure, (d) (iv) Aorta ® has high oxygen concentration and high pressure, , 15. In the figure given below, the structures associated with human kidneys are marked, (X, Y and Z)., , SAMPLE PAPER 4, , X, , Y, Aorta, Z, , The relative concentration of urea in, (a) X is sometimes higher than Y, (b) Y is always higher than Z, (c) Y is always lower than Z, (d) Z is sometimes lower than X, , Vena cava

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123, , CBSE Sample Paper Science Class X (Term I), , 16. Observe the diagram of human respiratory system., , A, B, , C, D, , Match the labelling referred in Column I and correlate with characteristics/functions in, Column II., Column I, , Codes, A, (a) 1, (c) 4, , Column II, , A, , 1. Air passages inside lungs that branch like tree limbs, , B, , 2. Its walls comprises of C-shaped cartilaginous rings, , C, , 3. It forms the base of chest cavity, , D, , 4. It is the common pathway for air and the food, , B, 2, 2, , C, 3, 3, , D, 4, 1, , A, (b) 2, (d) 4, , B, 4, 2, , C, 1, 1, , D, 3, 3, , 17. In an experiment, the image of distant object formed by a concave mirror is obtained, on a screen. The focal length of the mirror is the distance between, (a) mirror and the object, (b) mirror and the screen, (c) object and the screen, (d) half the distance between mirror and screen, , 18. Which of the following ray diagrams is correct for the ray of light incident on a lens, shown in figure?, , O, , F, , F, , (B), , O, , O, , F, , (b) B, , F, , F, , (C), , (a) A, , F, , (D), , (c) C, , (d) D, , SAMPLE PAPER 4, , (A), , F, , O, , F

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124, , CBSE Sample Paper Science Class X (Term I), , 19. Which of the following is not an example of refraction of light?, (a) A lemon kept in water in glass tumbler appears to be bigger than its actual size., (b) The letters appear to be lower when viewed through glass slab placed over the document., (c) A pencil partially immersed in water appears to be bent., (d) The coin at bottom of water tank appears to be raised when viewed from top., , 20. A ray of light passes through 3 media A, B and C. Wavelength of light in medium A,, medium B and medium C is 2000 Å, 3000 Å, 4000 Å, respectively. Based on this data, arrange the frequencies of light in correct order., (a) Frequency in medium A < frequency in medium B < Frequency in medium C., (b) Frequency in medium C < Frequency in medium B < Frequency in medium A., (c) Frequency in medium C = 2 ´ Frequency of medium A, (d) Frequency in medium A = Frequency in medium B = Frequency in medium C., , 21. Jay have two thin lenses, convex and concave of focal length 25 cm, then which of the, following is correct about their focal length?, (a) f concave = f convex, (b) f concave > f convex, f, (c) f concave < f convex, (d) concave = 1, f convex, , 22. Ram while performing an experiment on tracing the path of a light ray passing through a, rectangular glass slab, measured three angles marked as q 1 , q 2 and q 3 in the figure., q1, q2, , q3, , Which one of the following is correct?, (a) angle q 1 is less than angle q 2 but equal to angle q 3, (b) angle q 2 is equal to angle q 3, (c) Sum of angle q 1 and angle q 2 is equal to angle q 3, (d) angle q 3 is greater than angle q 2, , 23. A ray of light incident on a prism is refracted as shown. The correct path of light, , SAMPLE PAPER 4, , corresponds to, , (i), , (ii), , (iii), , (a) (ii), , (b) (i), , (iv), , (c) (iv), , (d) (iii)

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125, , CBSE Sample Paper Science Class X (Term I), , 24., Increasing, altitude, , Earth, , The Earth’s atmosphere consists of layers of varying densities. The air layer of, atmosphere whose temperature is less than the other layer behaves as, (a) optically rarer medium, (b) optically denser medium, (c) optically inactive medium, (d) neither denser nor rarer, , Section B, Section B consists of 24 questions (Sl. No. 25 to 48). Attempt any 20 questions from this section. The first, attempted 20 questions would be evaluated., , 25. Zn + H 2 O ¾® A + B, (Steam), , Identify the correct option from the given table which represents the type of reaction and gas, evolved., Displacement reaction, , Gas evolved, , (a), , ü, , û, , (b), , û, , ü, , (c), , ü, , ü, , (d), , û, , û, , 26. The graph given below depicted a record of the pH value of rain in different years. In, which year, the concentration of hydrogen ion is minimum?, 6.00, 5.00, 4.00, pH 3.00, value 2.00, 1.00, 0, , (a) 2000, , 2000 2002 2004 2008 2010 2014 2018, Rain pH value, , (b) 2004, , (c) 2008, , (d) 2014, , (I), , Dilute HCl, , Dilute NaOH, , Dilute HCl, , Dilute NaOH, , Na2CO3, , Zinc, , Zinc, , Na2CO3, , (II), , (III), , Among the four setups, only IV does not evolve gas., , (IV), , SAMPLE PAPER 4, , 27. Four students were asked by their teacher to arrange the set ups I-IV as given below

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126, , CBSE Sample Paper Science Class X (Term I), , What is the reason for different behaviour in test tube IV?, (a) Neutralisation takes place, (b) Precipitation reaction occurs., (c) Na 2 CO 3 does not react with dil. NaOH, (d) Na 2 CO 3 reacts with dil.NaOH and form carbonic acid and water., , 28. The table shown below gives information about four elements A, B, C and D., Elements, , Electronic configuration, , A, , 2, 8, 2, , B, , 2, 8, 7, , C, , 2, 8, 6, , D, , 2, 8, 3, , Identify the elements which can make ionic compound., (a) A and B, (b) B and C, (c) C and D, (d) A and C, , 29. Sunita observed that the yellow stain of curry on a white shirt remains unchanged, when it is dipped with vinegar but it turns reddish brown when it washed with soap., What might be the reason for her observation?, I. Soap is basic in nature., II. Soap is acidic in nature., III. Turmeric is a natural indicator which changes its colour to red in bases., IV. Turmeric is a natural indicator which changes its colour to red in acids., (a) I and II, (b) I and III, (c) II and IV, (d) II and III, , 30. Four students I, II, III and IV were asked to examine the changes for blue and red, litmus paper strips with dil. HCl (solution A) and dil. NaOH (solution B). The, following observation were reported by the four students. The sign (-) indicating no, colour changes., , SAMPLE PAPER 4, , I., , II., , III., , Litmus, , A, , B, , Blue, , –, , Red, , Red, , –, , Blue, , Litmus, , A, , B, , Blue, , Red, , Red, , –, , Blue, , Litmus, , A, , B, , Blue, , Red, , Red, , Red, , Blue, , Blue

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127, , CBSE Sample Paper Science Class X (Term I), , IV, , Litmus, , A, , B, , Blue, , Blue, , Blue, , Red, , Red, , Red, , Which of the above observation(s) is/are correct?, (a) I and II, (b) III and IV, (c) II and IV, , (d) Only II, , Direction (Q. No. 31 to 34) Consist of two statements – Assertion (A) and Reason (R). Answer these, questions selecting the appropriate option given below :, (a) Both A and R are true and R is the correct explanation of A., (b) Both A and R are true, but R is not the correct explanation of A., (c) A is true, but R is false., (d) A is false, but R is true., , 31. Assertion The following chemical equation,, 7, 2 C 6 H 6 + O 2 ¾® 4 CO 2 + 3 H 2 O, 2, is a balanced chemical equation., Reason In a balanced chemical equation, the total number of atoms of each element is, equal on both sides of the equation., , 32. Assertion Acetic acid (CH 3 COOH) is a weak acid., , Reason Acetic acid produces very little OH - ions on dissociation in water., , 33. Assertion Exchange of oxygen and carbon dioxide occurs between trachea and the, blood vessels., Reason Oxygen diffuses into the blood vessels and carbon dioxide diffuses out from, the blood vessels., , 34. Assertion Newton showed that the seven coloured lights of the spectrum can be, recombined to give back white light., Reason When a beam of white light is passed through a glass prism, a band of seven, colours is formed on a white screen., , 35. Which one of the following set of observation will be correct (ü mark shows reaction, takes place, ( û shows reaction does not take place)?, Metal added, , Solution taken, FeSO 4, , CuSO 4, , Al 2 (SO 4 ) 3, , I. Zn, , û, , ü, , û, , II. Fe, , ü, , û, , ü, , III. Cu, , û, , ü, , û, , IV. Al, , ü, , ü, , ü, , û, û, û, û, , (a) I, , (b) II, , (c) III, , 36. The correct sequence of anaerobic reaction in yeast is, Cytoplasm, , Mitochondria, , Cytoplasm, , Cytoplasm, , Cytoplasm, , Mitochondria, , Cytoplasm, , Cytoplasm, , (a) Glucose ¾¾¾® Pyruvate ¾¾¾¾® Ethanol + Carbon dioxide, (b) Glucose ¾¾¾® Pyruvate ¾¾¾® Lactic acid, (c) Glucose ¾¾¾® Pyruvate ¾¾¾¾® Lactic acid, (d) Glucose ¾¾¾® Pyruvate ¾¾¾® Ethanol + Carbon dioxide, , (d) IV, , SAMPLE PAPER 4, , ZnSO 4

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128, , CBSE Sample Paper Science Class X (Term I), , 37. The following changes take place in an athlete’s body during 100 m race. Which change, occurs first?, (a) Increased availability of oxygen to muscles, (b) Increased breathing rate, (c) Increased carbon dioxide concentration in the blood, (d) Increased production of carbon dioxide by muscles, , 38. Which one of the following statement is incorrect about the human circulatory system?, (a) Valves ensure that the blood does not flow backwards, (b) Arteries are thin walled to maintain blood pressure in them, (c) The normal systolic pressure is about 120 mm of Hg and diastolic pressure is about 80 mm, of Hg., (d) Pulmonary vein carry oxygenated blood from lungs, , 39. The power of a concave lens of focal length 1 mm is, (a) 0.01 D, (c) 0.001 D, , (b) 100 D, (d) 1000 D, , 40. When a plane mirror is rotated through a certain angle (q), the reflected ray turns, through a twice or much and the size of image, (a) becomes twice the size of object, (b) becomes half the size of object, (c) becomes negligibly small, (d) remains same as that of object, , 41. What is the nature of the food in the stomach and what is done for the pancreatic, enzymes to act?, (a) Acidic, made more acidic, (b) Acidic, made alkaline, (c) Alkaline, made acidic, (d) Alkaline, made more alkaline, , 42. During anaerobic alcoholic fermentation by yeast, alcohol is formed, (a) in the yeast cell’s vacuole, (c) outside the yeast cell, , (b) in the yeast cell’s mitochondrion, (d) within the yeast cell, , 43. Refractive index of ethanol is 1.36 and it is known that benzene is optically denser than, ethanol. The refractive index of benzene could be, (a) 1.35, (b) 1.28, (c) 1.34, (d) 1.50, , 44., , SAMPLE PAPER 4, , A, B, , B', A', , F, , P, , The above mirror has a focal length of 10 cm. The object is placed at a distance of 30 cm from, the pole. Find the magnification of object., 1, 1, (a) (b), 2, 2, 1, 1, (c), (d) 4, 4

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129, , CBSE Sample Paper Science Class X (Term I), , 45., Principal F1, axis, , F2, f, , (A), , F2, , O, , f, , (B), , While studying the given above diagrams, Radha concluded the following, (i) The image of the object will be inverted, (ii) The point of convergence of parallel beam by convex lens is focal point., (iii) The image in case (B) is virtual one, (iv) The beam of light, incident on the convex lens (B) is not parallel to principal axis., Which of the above statements are correct?, (a) (i) and (ii), (b) (iii) and (iv), (c) (i), (ii) and (iv), (d) (i), (ii), (iii) and (iv), , 46. A ray of light undergoes refraction from medium I to medium II as shown in figure., If speed of light in medium I is v, then its value in medium II is,, N, , X, , I, II, , 60º, 30º, , Y, , N', , (a) 3v, , v, (b), 3, , (c) 2v, , (d), , v, 2, , 47. A mark on the bottom of the liquid appears to rise by 0.1 m. The depth of the liquid is, 1 m. Find the refractive index of the liquid., (a) 0.9, (b) 1.1, (c) 1.33, , (d) 1.5, , physical properties., Properties, , A, , B, , C, , D, , Malleable, , Yes, , No, , No, , Yes, , Ductile, , Yes, , No, , No, , Yes, , Melting point, , High, , Low, , Low, , High, , Lustre, , No, , Yes, , No, , Yes, , SAMPLE PAPER 4, , 48. A metallic interior designing company tested few elements on the basis of their

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130, , CBSE Sample Paper Science Class X (Term I), , Which of the above elements were disapproved for usage by the company?, (a) A, B, C, (b) B, C, D, (c) A, B, D, (d) A, C, D, , Section C, This Section C consists of three Cases followed by questions. There are a total of 12 questions in, this section. Attempt any 10 questions from this section. The first attempted 10 questions would be, evaluated., , Case I The sample pieces of five metals M, N, O, P and Q are added to the tabulated salt, solutions separately., The results observed are shown in the table given below., Metal, , Salt solutions, CuSO 4, , FeSO 4, , ZnSO 4, , AgNO 3, , M, , No change, , No change, , No change, , A coating on metal, , N, , Grey deposit, , Brown coating, , No change, , A coating on metal, , O, , No change, , No change, , No change, , No change, , P, , No change, , –, , No change, , A coating on metal, , Q, , Brownish-red deposit, , Brown coating, , Grey coating, , New coating, , Read the observations carefully and give the answer of the following questions, , 49. Which is the most reactive metal?, (a) N, (c) P, , (b) O, (d) Q, , 50. Which is the least reactive metal?, (a) M, (c) Q, , (b) O, (d) N, , 51. What will happen when these metal reacts with acid?, (a) Salt is formed along with H 2 gas, (b) Salt is formed along with CO 2 gas, (c) Metal oxide is formed along with water, (d) Metal oxide is formed along with hydrogen gas., , SAMPLE PAPER 4, , 52. Which type of reaction is observed in the given data?, (a) Decomposition reaction, (b) Displacement reaction, (c) Neutralisation reaction, (d) Precipitation reaction

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131, , CBSE Sample Paper Science Class X (Term I), , Case II. Digestion is a catabolic process where complex and large components of food are, broken down into simpler forms with the help of hydrolytic enzymes which are absorbed by, different parts of the body., Answer the questions on the basis of your understanding of the following table and related, concepts., Parts of the human, digestive system, , Main functions, , Main type of, enzymes, acting, , Sources of, the enzymes, , Substances, on which, enzymes act, , Products of, digestion, , Mouth, teeth, tongue, and salivary glands, , Food broken, down into smaller, pieces, some, digestion of starch, , Amylase, , X, , Starch, , Complex, sugars, , Oesophagus, , Transports food to, stomach, , —, , —, , —, , —, , Stomach, , Digestion of, protein, , Small intestine, , Final digestion, followed by, absorption of, nutrients, , Protein, fragments, and some, amino acids, , Y, , Proteins, , Amylase,, lipase and, protease, , Z, , Complex, sugars, fats, and protein, fragments, , Simple, sugars, fatty, acids,, glycerol and, amino acids, , Large intestine, , Salts, vitamins and, water absorbed, from wastes,, undigested wastes, collected, , —, , —, , —, , —, , Anus, , Elimination of, wastes, , —, , —, , —, , —, , Protease, , 53. Based on the information in the table, which substance breaks down starch., (a) Lipase, (c) Trypsin, , (b) Amylase, (d) Protease, , 54. What is the composition of gastric juice?, (a) HCl, Pepsin, Lipase, (c) Pepsin, HCl, Mucus, , (b) HCl, Lipase, Amylase, (d) Mucus, Pepsin, Bile, , 55. Identify the correct source of enzymes in mouth, stomach and small intestine labelled, , 56. Name the parts of the human digestive system where digestion of food does not take, place., (i) Oesophagus, , (ii) Mouth, , (iii) Large intestine, , (iv) Anus, , SAMPLE PAPER 4, , as X, Y and Z., (a) X-Salivary glands, Y-Gastric glands, Z-Pancreas and small intestine, (b) X-Salivary glands, Y-Gastric glands, Z-stomach, (c) X-Saliva, Y-HCl, Z-Liver, (d) X-Parotid glands, Y-Mucous, Z-Pancreas

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132, , CBSE Sample Paper Science Class X (Term I), , Choose the correct option., (a) (i) and (iv), (c) (iii) and (iv), , (b) (i), (iii) and (iv), (d) (i), (ii), (iii) and (iv), , Case III. Uma needs a telescope to see the stars in the night sky. She knows that telescopes are, used to observe objects which are very far from us. So, she decided to make a simple telescope., She used two lenses L1 and L2 as objective lens and eyepiece, respectively. A parallel beam of, light is focused by the objective lenses L1 which is bigger in size and then light passes through, an eyepiece L2 (smaller lens) forming a magnified image., , Eye, , L1, (objective lens), , L2, (eye piece), , So, to see far away, she needed a big powerful lens. Unfortunately, she realised that big lenses, are very heavy in holding a telescope at right position., , 57. Based on the diagram of telescope, which lens is used by Uma?, (a) Plano-convex lens, (c) Bi-focal lens, , (b) Double convex lens, (d) Concave lens, , 58. If the power of L1 and L2 are in the ratio of 16 : 9, what would be the ratio of the focal, length of L2 and L1 ?, (a) 3 : 4, (b) 16 : 9, , (c) 9 : 16, , (d) 4 : 3, , 59. While doing this demonstration, her friend noted some observations as follows, (i), (ii), (iii), (iv), , The power of the objective lens of a telescope kept as small as possible., The aperture of objective lens or mirror of a telescope takes as large., The objective of the telescope have large focal length., The power of eyepiece and objective is same., , Which one combination of the above statements is correct?, (a) (i), (ii) and (iii) are correct, (b) (ii) and (iv) are correct, (c) (iii) and (iv) are correct, (d) (i), (iii), (iv) are correct, , 60. Convex lens is not used in which one of the following?, , SAMPLE PAPER 4, , (a) Telescope, (c) Flashlight, , (b) Microscope, (d) Magnifying glass

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OMR SHEET, , SP 4, , Roll No., Sub Code., , Student Name, , Instructions, Use black or blue ball point pens and avoid Gel & Fountain pens for filling the OMR sheet., Darken the bubbles completely. Don’t put a tick mark or a cross mark, half-filled or over-filled bubbles will not be read, by the software., Correct, , ✔, , ✗, , Incorrect, , Incorrect, , Incorrect, , Do not write anything on the OMR Sheet., Multiple markings are invalid., , 1, , 21, , 41, , 2, , 22, , 42, , 3, , 23, , 43, , 4, , 24, , 44, , 5, , 25, , 45, , 6, , 26, , 46, , 7, , 27, , 47, , 8, , 28, , 48, , 9, , 29, , 49, , 10, , 30, , 50, , 11, , 31, , 51, , 12, , 32, , 52, , 13, , 33, , 53, , 14, , 34, , 54, , 15, , 35, , 55, , 16, , 36, , 56, , 17, , 37, , 57, , 18, , 38, , 58, , 19, , 39, , 59, , 20, , 40, , 60, , Check Your Performance, Total Questions:, Total Correct Questions:, , If Your Score is, , Score Percentage =, , Total Correct Questions, Total Questions, , × 100, , Less than 60%, > Average (Revise the concepts again), Greater than 60% but less than 75% > Good (Do more practice), Above 75%, > Excellent (Keep it on)

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134, , CBSE Sample Paper Science Class X (Term I), , Answers, 1. (b), 11. (d), , 2. (a), 12. (d), , 3. (d), 13. (c), , 4. (c), 14. (d), , 5. (a), 15. (c), , 21. (c), 31. (d), 41. (b), , 22. (a), 32. (c), 42. (d), , 23. (c), 33. (d), 43. (d), , 24. (b), 34. (b), 44. (a), , 25. (c), 35. (d), 45. (c), , 51. (a), , 52. (b), , 53. (b), , 54. (c), , 55. (a), , 6. (a), 16. (b), 26. (d), , 7. (b), 17. (b), 27. (c), , 8. (c), 18. (a), 28. (d), , 9. (a), 19. (b), 29. (b), , 10. (d), 20. (d), 30. (d), , 36. (d), 46. (a), , 37. (d), 47. (b), , 38. (b), 48. (a), , 39. (d), 49. (d), , 40. (d), 50. (b), , 56. (b), , 57. (b), , 58. (b), , 59. (a), , 60. (c), , EXPLANATIONS, 1. The reaction involved, Fe + CuSO 4 ¾® FeSO 4 + Cu, (Blue), , (Green), , Due to the displacement reaction, the formation, of FeSO 4 (green in colour) takes place., 2. When metal reacts with dil. HCl, it produces, salt and hydrogen gas. So, according to the, experiment,, Zn + 2HCl ¾® ZnCl 2 + H 2, (diluted), , 3. When metal carbonate reacts with dil. HCl, it, produces salt, carbon dioxide and water., Metal carbonate+ dil. HCl ¾®Salt + CO 2 + H 2O, So, (i) and (iii) are correct combination among, others., 4. Chemical equation (c) is balanced one as total, number of atoms of each element are equal on, both sides of the equation., Cu ( s) + 4 HNO 3 ( aq) ¾® Cu(NO 3 )2( aq), + 2 NO 2(g) + 2 H 2O ( l ), 5. As pH value is indirectly proportional to, concentration of H + ions, thus, ‘A’ curve is, correct., 6. H 2S + Cl 2 ¾® S + 2 HCl, , SAMPLE PAPER 4, , In this reaction, H 2S is oxidised to S by, removing hydrogen atoms. Hence, H 2S acts as, reducing agent as well because the substance, that oxidised is called reducing agent., 7. The chemical reaction between copper, sulphate and hydrogen sulphide involves:, CuSO 4 + H 2S ¾® CuS + H 2SO 4, It is a double displacement reaction because, both ions, Cu 2 + and H + exchange their, positions and form two new compounds, CuS, and H 2SO 4 ., 8. Sodium acetate (CH 3COONa) is formed by, reaction between CH 3COOH (parent acid) and, NaOH (parent base)., CH 3COOH + NaOH ® CH 3COONa + H 2O, , 9. While diluting a concentrated acid, one should, add acid to water with constant stirring to, avoid any mishappening related to heat, generation throughout the process as dilution, of conc. acid is an exothermic reaction., 10. All the given statements are correct about the, importance of chemical equation in a chemical, reaction., 11. Option (d) is incorrect pair. In large intestine, absorption of water and salt from undigested, food material occurs. The rest of the material is, removed from the body via anus., 12. The part labelled as X is urinary bladder., The urinary bladder is a muscular sac in the, pelvis, just above and behind the pubic bone., The function of urinary bladder is to store, urine., 13. The lining of alimentary canal has muscles that, contract rhythmically in order to push the food, forward in the food pipe. These peristaltic, movements occur all along the gut., 14. In aorta, blood has high oxygen concentration, as it has entered from lungs and is transported, to the different parts of the body under high, pressure., 15. The structures are labelled as, X—Renal vein, Y—Renal artery, Z—Ureter, The renal artery (Y) carries oxygenated blood, to the kidneys from the heart. This blood, contains negligible amount of urea. On the, other hand, the ureters (Z) transport urine, from the kidneys to the urinary bladder., The urine contains comparatively high amount, of urea to be excreted out. Thus, the relative, concentration of urea in Y is always lower than, that in Z.

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135, , CBSE Sample Paper Science Class X (Term I), , 16. The structures are labelled as, A - Trachea, B - Pharynx, C - Bronchioles, D - Diaphragm, Trachea is also called windpipe, is a tube that, serves as a passage for air. The walls of trachea, comprises C-shaped cartilaginous rings which, prevents trachea from collapsing., Pharynx is a common pathway for the air and, the food. The flap-like structure called, epiglottis is present that prevents food, particles from going into the food pipe., Bronchi are subdivided into smaller tubes, called bronchioles. Bronchioles deliver air to, diffuse network of alveoli., Diaphragm forms the base of chest cavity., , 23. The correct path of light which is incident on a, prism is, , 17. The image of distant object is formed at focus., So, the focal length of the mirror is the distance, between the mirror and the screen., , 25. Zn + H 2O, , 18. A ray of light passing through the principal focus, of a convex lens after refraction from a convex, lens, will emerge parallel to the principal axis or, vice-versa. If a ray of light passing through the, optical centre of the lens, emerges without any, deviation after refraction and if light moves, along principal axis, the same rule applies., 19. Due to refraction of light at the surface of, water, a lemon inside water appears to be, bigger than actual, a pencil partially immersed, in water appears to be bent, a coin at bottom of, water tank appears to be raised and the letter, when viewed from glass slab appears to raised, over the document., 20. As the ray of light passes through different, media, its frequency does not change with the, value of refractive index., So, frequency in medium A, medium B and, medium C is equal., 21. Focal length of concave lens, fconcave = - 25 cm, Focal length of convex lens, fconvex = 25 cm, Þ, fconcave < fconvex, 22. Since, in glass slab experiment,, i, q2, r, , e, , Þ, , Ði > Ðr but Ðe = Ði, q 1 < q 2 but q 1 = q 3, , q3, , So, the layer whose temperature is less than, other layer behaves as optically denser, medium., (Steam), , ¾® ZnO + H 2­, , In this reaction zinc oxide is formed with, evolution of hydrogen gas and this reaction is, a type of displacement reaction because, oxygen is displaced from hydrogen to zinc., 26. In the graph, the pH value touched the higher, in year 2014. Hence, where pH value is, highest, the concentration of H + is lowest, because pH is inversely proportional to, concentration of H+ ions., 27. In IV setup, Na 2CO 3 does not react with dil., NaOH, hence there is a no evolution of gas., 28. A : 2, 8, 2 and C : 2, 8, 6, ‘A’ can lose 2 electrons and ‘C’ can gain 2, electrons to fulfill their stable electronic, configuration. ‘A’ easily transfer its 2 electrons, to C and make ionic bond., 29. In acidic medium, turmeric does not change its, yellow colour while in basic medium, it, changes its colour to red. Therefore, on, scrubbed with soap, it turns reddish-brown, which means soap is basic in nature., 30. Only observation II is correct among others., Because on addition of acid, blue litmus turns, red and on addition of base, red litmus turns, blue. However, acid does not change colour of, red litmus and base does not change the colour, of blue litmus., 31. A is false but R is true., In a balanced chemical equation, the total, number of atoms of each element are equal on, both sides of the equation moreover, the, correct balanced chemical equation is, 2 C2H6 + 7 O2 ¾® 4 CO2 + 6 H2O, , SAMPLE PAPER 4, , q1, , 24. Densities of different layers of earth depend, upon the presence of molecules in it. The layer, which is at cold place has closely spaced, molecules rather than layer at hot place where, molecules are apart.

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136, , CBSE Sample Paper Science Class X (Term I), , 32. A is true, but R is false., Acetic acid is a weak acid because it does not, dissociates completely into ions (H + and, CH 3COO - ) in water., 33. A is false, but R is true., Exchange of gases like oxygen and carbon, dioxide occurs between the alveoli and the, blood vessels. Oxygen diffuses from alveoli, into the blood vessels and carbon dioxide, diffuses from the blood vessels to the alveoli., 34. Both A and R are true, but R is not correct, explanation of A., Newton showed that the reverse of dispersion, of light is possible. The light gets dispersed, when passes through the first prism. The, second prism receives all the seven coloured, rays from first prism and recombines them into, original white light., 35. Al being most reactive element, reacts with all, the solutions taken., Al + ZnSO 4 ¾® Al 2(SO 4) 3 + Zn, Al + FeSO4 ¾® Al2(SO4 )3 + Fe, Al + CuSO4 ¾® Al2(SO4 )3 + Cu, 36. Glucose is converted into pyruvate (glycolysis), in the cytoplasm of the cell. It is the first stage, of respiration. After glycolysis, pyruvate gets, converted into ethanol and carbon dioxide, during anaerobic respiration in cytoplasm of, yeast., 37. The first change that occurs in athelete’s body, is decrease in oxygen availability in muscle, cells and cells start anaerobic respiration. In, order to provide energy for 100 m race,, respiration increases in athelete’s muscles and, CO 2 is produced., 6 CO2 + C6H12O6 ¾® 6 H2O + 6 CO2 + Energy, , SAMPLE PAPER 4, , 38. Arteries are thick walled due to high pressure, of oxygenated blood in them. Veins have thin, walls because the deoxygenated blood is no, longer under high pressure., 39. Given, focal length = 1 mm = 10 - 3 m, 1, \, P=, f( in m ), P=, , Þ, , 1, , 10 - 3, P = 1000 D, , acidic food from the stomach is made alkaline, by the action of bile., 42. During anaerobic alcoholic fermentation by, yeast, alcohol is formed within the yeast cell. It, is a incomplete breakdown of pyruvate into, ethanol and carbon dioxide to release energy., The reaction of anaerobic alcoholic, fermentation can Be Summarised as :, In cytoplasm, , Glucose ¾¾¾¾® Pyruvate + Energy, , ( 6 molecules ), , Absence of oxygen, , ¾¾¾¾¾¾® Ethanol +, in years, , CO2 + 2 ATP, ( 2 molecules ) ( 2 molecules ) (Energy), , 43. As benzene is denser than ethanol. So, its, refractive index must be greater than ethanol., i.e. m benzene = 1.50, 44. Given, u = - 30 cm, f = - 10 cm, By mirror formula,, 1 1 1, + =, v u f, 1, 1, 1, +, =, v - 30 - 10, 1, 1, 1, 1, Þ, =, =v 30 10, 15, or, v = - 15 cm, v - ( - 15 ), 1, Magnification, m = - =, Þm= 2, u, - 30, 45. The image formed by convex lens (when object, is at infinity) is at focus, real and inverted. In, case (A), the beam of light is coming parallel to, principal axis while in case (B) the beam of, light incident on lens is not parallel to principal, axis but the converging point is focus of the, lens., 46. Given, i = 90° - 60° = 30°, r = 90° - 30° = 60°, sin i v, =, sin r v ¢, sin r, sin 60°, ´v, ´v=, v¢ =, sin i, sin 30°, , Using Snell’s law, m =, Þ, , =, , 3, ´ 2 ´ v = 3v, 2, , 47. Given, real depth = 1 m, Apparent depth = 1 - 0.1 = 0.9 m, Real depth, Apparent depth, 1, =, 0.9, , Refractive index of the liquid =, , 40. Rotation of plane mirror, through any angle, doesn’t affect the size of image., 41. The pancreatic enzymes are optimally active in, alkaline pH in the small intestine. Thus, the, , ( 2 molecules ), , Þ, , m = 1.1

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137, , CBSE Sample Paper Science Class X (Term I), , 48. For metallic interior designing, the element, should have lustre, ductility, malleability and, high melting point and D have all these, properties. So, except D, all the other elements, were disapproved., 49. Q is the most reactive metal because it reacts, with all salt solutions., 50. O is the least reactive metal because it shows, least reactivity with salt solutions and it does, not react with any solution., 51. Acid + Metal ¾® Salt + H 2 ­, When an acid reacts with metal, there is, formation of salt with evolution of hydrogen gas., 52. The reactions between metal and salt solution, involve displacement reaction depends on the, reactivity of metal., 53. Amylase is a carbohydrate digestive enzyme,, which is responsible for the breakdown of, starch into smaller molecules., 54. The gastric juice secreted by the gastric glands, of the stomach includes HCl, pepsin and, mucus., 55. The labelled source of enzymes are, X—Salivary glands, which secretes amylase in, the mouth., Y—Gastric glands, which secretes gastric juices, in the stomach., , Z—Pancreas and small intestine, which, secretes enzymes in the small intestine., 56. In the human alimentary canal, the parts, where digestion of food does not takes place is, the oesophagus, the large intestine and the, anus., 57. As shown in the given diagram, Uma would, need double convex lens in order to make, telescope., P 16, 58. Given, 1 =, P2, 9, 1, As,, Pµ, f, f2 16, P1, =, =, Þ, P2, f1, 9, 59. The objective lens of small power has a large, focal length which gives a high magnifying, power of the telescope., If the aperture of objective lens is large, it, gathers more light rays, so that brighter image, is formed., The power of eyepiece is larger than objective, due to its small focal length., 60. Convex lens is used in telescopes,, microscopes, magnifying glass, etc. Concave, lens is used in flashlights to get a parallel, beam of light., , SAMPLE PAPER 4

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SAMPLE PAPER 5, SCIENCE, A Highly Simulated Practice Questions Paper, for CBSE Class X (Term I) Examination, , Instructions, (i) This paper is divided into three Sections:, (a) Section A – Contains 24 questions. Attempt any 20 questions., (b) Section B – Contains 24 questions. Attempt any 20 questions., (c) Section C – Contains 12 questions. Attempt any 10 questions., (ii) Each questions carries 0.80 mark., (iii) There is NO negative marking., Maximum Marks : 40, Time allowed : 90 Min, , Roll No., , Section A, Section-A consists of 24 questions. Attempt any 20 questions from this section. The first attempted 20, questions would be evaluated., , 1. 10 mL of HCl and 10 mL of NaOH solutions are taken in two separate beakers labelled, I and II, respectively., On adding zinc granules to both beakers, it is observed that at room temperature., (a) Gas is evolved vigorously in both the beakers, (b) Gas is evolved vigorously in beaker I and not in the beaker II, (c) Gas is evolved vigorously in beaker II but not in the beaker I, (d) No gas is evolved in either of the two beakers, , 2. What type of reaction is observed in this beaker ?, , Iron, container, , H 2O, , CaO, , (a) Endothermic, (c) Displacement, , (b) Exothermic, (d) Precipitation

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139, , CBSE Sample Paper Science Class X (Term I), , 3., , Metal oxide, Dil.HCl, , ?, , Salt, , Which of the following two combinations are correct ?, Metal, , Gas evolved, , 1. Cu, , No, , 2. Fe, , No, , 3. Mg, , Yes, , 4. Zn, , Yes, , (a) 1 and 2, , (b) 2 and 3, , (c) 3 and 4, , (d) 1 and 4, , 4. Which of the following reaction involves the formation of yellow coloured product ?, (a) 2 KClO 3 ¾Heat, ¾¾® 2 KCl + 3O 2, , (b) NH 3 + HCl ¾® NH 4 Cl, , (c) CuSO4 + H2 S ¾® CuS + H2 SO4, , D, (d) 2Pb 3 O4 ¾¾, ® 6PbO + O2, , 5. The graph given below depicts the neutralisation reaction in which NaOH is added to, HCl., C, , 14, pH 7, value, , B, A, , O, , Volume of NaOH, added (mL), , Which letter denotes the highly basic area?, (a) A, (b) B, (c) C, , (d) Both B and C, , 6. In the following reaction,, , 7. When zinc reacts with dilute hydrochloric acid, then, (a) the surface of zinc becomes brighter, (b) the surface of zinc becomes black and dull, (c) the metal turns into powder, (d) the reaction mixture turns green, , SAMPLE PAPER 5, , 3Fe + 4H 2 O ¾® Fe 3 O 4 + 4H 2, Identify the correctly representation of the substance reduced and the oxidising agent., Substance reduced, Oxidising agent, (a), Fe, Fe, (b), H2 O, H2 O, (c), Fe 3 O4, H2, (d), 4H2, Fe 3 O4

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140, , CBSE Sample Paper Science Class X (Term I), , 8. Which of the given options correctly represents the parent acid and base of ammonium, sulphate?, Parent acid, (a) HCl, (b) H2 SO 4, (c) NH3, (d) H2 SO 4, , Parent base, NH3, NH4 OH, NaOH, NH3, , 9. The products formed by chlor-alkali process are, (b) Cl 2 , Na 2 CO3 and H2 O, (d) NaCl, Cl 2 and H2, , (a) H2 , Cl 2 and NaOH, (c) NaOH , Cl 2 and NaCl, , 10. How can you specify the chemical reaction between calcium oxide and water ?, (a) Change in colour of product, (b) Change in temperature of mixture, (c) Change in the state of mixture, (d) Evolution of hydrogen gas, , 11. The diagram shows part of the human gas exchange system., W, , X, Y, Z, , Select the option which gives correct identification and main function and/or, characteristics of the shown labels., (a) X–Trachea : It serves as a passage for food., (b) Y– Bronchiole : It deliver air to the capillaries., (c) W - Larynx : It serves as chamber for both respiratory and digestive functions., (d) Z - Bronchus : It act as passage way that leads from the trachea to lungs., , 12. The diagram shows the human gut. Which numbered structures secrete digestive, enzymes?, Oesophagus, (food pipe), 6, 1, , SAMPLE PAPER 5, , 5, , 2, , 4, 3, , (a) 1-Stomach, 2-Pancreas, 3-Small intestine, 4-Large intestine, (b) 1-Stomach, 2-Pancreas, 3-Small intestine, 6-Mouth, (c) 2-Pancreas, 3-Small intestine, 4-Large intestine, 5-Liver, (d) -2-Pancreas, 3-Small intestine, 5-Liver, 6-Mouth

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141, , CBSE Sample Paper Science Class X (Term I), , 13. Which of the following structures is involved in gaseous exchange in woody stem of a, plant?, (a) Stomata, (c) Guard cell, , (b) Lenticel, (d) Epidermis, , 14. When a person eats some egg white, proteins and water enter the stomach. Which, substances are found leaving the stomach and leaving the small intestine?, (a), (b), (c), (d), , Leaving the stomach, Amino acids and water, Fatty acids, glycerol and water, Protein and water, Protein, amino acids and water, , Leaving the small intestine, Amino acids and water, Fatty acids, glycerol and water, Fatty acids and glycerol, Water, , 15. Identify the correct phase of nutrition in Amoeba represented in the diagram given, below., Nucleus, , (a), , Food particle, , (b), , (c), , Food particle, , (d), , (a) Amoeba ingests the food particle with the help of cilia present all over the body, (b) The finger-like extension fuses over the food particle to form food vacuole, (c) The undigested food comes out of the body with the help of pseudopodia, (d) Inside the Amoeba the simpler substances diffused into the nucleus, , 16. Observe the diagram of human circulatory system., Vena cava receiving, blood from, upper body, , Aorta, Pulmonary, arteries, , C, , Vena cava receiving, blood from, lower body, , Valves, A, , D, , Interventricular septum(dividing wall), , SAMPLE PAPER 5, , Pulmonary, veins, , B

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142, , CBSE Sample Paper Science Class X (Term I), , Match the labelling referred in Column I and correlate it with Column II., Column I, , Column II, , A, , 1., , Oxygenated blood from lungs transported to it., , B, , 2., , Oxygenated blood from it transported to body part., , C, , 3., , Deoxygenated blood from it goes to lungs., , D, , 4., , Deoxygenated blood from body flows to it., , Codes, A B, (a) 4 3, (c) 3 4, , C, 2, 1, , D, 1, 2, , A B, (b) 3 4, (d) 4 1, , C D, 2 1, 3 2, , 17. A person travelling at day time in foggy weather is not able to see things clearly on, road because of, (a) refractive index of the fog is very high, (b) light suffers internal refraction by droplets, (c) fog absorbs light rays, (d) light is scattered by the tiny water droplets, , 18. Choose the correct depiction for dispersion of white light on passing through a prism., ig, ite l, Wh, , ht, , A, Red, Violet, , ite, Wh, , t, ligh, , Green, Red, , (i), , ite l, Wh, , t, , ig h, , (ii), , A, Violet, Yellow, , t, igh, , (b) (ii), , A, , ite l, Wh, , (iii), , (a) (i), , A, , Blue, Green, (iv), , (c) (iii), , (d) (iv), 3, 19. Linear magnification of an image formed by a mirror is . The mirror is, 2, (a) a plane mirror, (b) a concave mirror, (c) a convex mirror, (d) Both concave mirror and convex mirror, , 20. A convex lens made up of glass is immersed in a liquid of refractive index greater than, , SAMPLE PAPER 5, , that of glass as shown in the figure, , Choose the correct statement of the following., (a) Convex lens will act as diverging lens., (b) Convex lens will disappear in liquid., (c) Convex lens will form magnified image in liquid., (d) Convex lens remains converging lens.

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143, , CBSE Sample Paper Science Class X (Term I), , 21. Three students A, B and C measured the focal length of a convex lens and labelled the, distance as f1 , f 2 and f 3 , respectively. Student A saw sharp image, student B saw, slightly larger blurred image and student C saw a slightly smaller blurred image on, the screen. The relation between the three measurements would most likely be, (b) f1 < f 2 and f 3, (a) f1 = f 2 = f 3, (c) f 3 < f1 < f 2, (d) f1 < f 2 and f1 = f 3, , 22. Which of the following is the correct diagram of a ray light after reflection at the, mirror?, F, , P, , C, , P, , (a), , F, , C, , (b), , P, , F, , C, , P, , (c), , F, , (d), , 23. To form an erect image twice the size of an object by using a convex lens of focal length, 20 cm, the object should be placed at a distance d from the optical centre of lens. Here,, d is, (a) d = 40 cm, (b) d = 20 cm, (c) d > 20 cm, (d) d < 20 cm, , 24. If a light ray IM is incident on the surface AB as shown, identify the correct emergent, ray., , I, A, , M, , B, , N, , D, P, , (a) Ray NP, , (b) Ray NQ, , O, R, Q, , C, S, , (c) Ray NR, , (d) Ray OS, , Section B, Section B consists of 24 questions (Sl. No. 25 to 48). Attempt any 20 questions from this section. The first, attempted 20 questions would be evaluated., , Identify the correct option from the given table which represents the type of reaction, and gas evolved (X)., Endothermic, Gas evolved, (a), P, O, (b), O, P, (c), P, P, (d), O, O, , SAMPLE PAPER 5, , D, 25. Lead tetraoxide ¾¾, ® PbO + X

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144, , CBSE Sample Paper Science Class X (Term I), , 26. The four solution A, B, C and D are taken and their concentration of H + ions are, , H+ concentration, , recorded., , A, , B, C, Solutions, , Which solution has highest pH value?, (a) A, (b) B, , D, , (c) C, , (d) D, , 27. The diagram shows the ways to observe the effect of heat on FeSO 4 crystals., , (I), , (II), , (III), , (IV), , Choose the correct way to observe the effect of heat on FeSO 4 crystals and the reason, behind it., (a) II-The poisonous gases are harmful to be inhaled, (b) III-The bubbles of any gas can come out of test tube, (c) I-The mouth of the test tube is hot, (d) None of the above, , 28. Four metals Zn, Fe, Cu and Al are taken and added to the following solutions one by, one. The results obtained are tabulated as :, Metal ZnSO 4 (aq), , FeSO 4 ( aq ), , CuSO 4 ( aq ), , Al 2 (SO 4 )3, , Zn, , –, , Displaced, , Displaced, , No reaction, , Fe, , No reaction, , –, , Displaced, , No reaction, , Cu, , No reaction, , No reaction, , –, , No reaction, , Al, , Displaced, , Displaced, , Displaced, , –, , SAMPLE PAPER 5, , From the above data, the decreasing order of reactivity of given metals is, (a) Al > Cu > Fe > Zn, , (b) Al > Zn > Fe > Cu, , (c) Al > Zn > Cu > Fe, , (d) Al < Fe < Cu < Zn, , 29. Amit checked the odour of onion juice and then he added few drop of onion juice in, dil. HCl and in dil. NaOH solution in separate test tubes. What would he observe ?, I. Odour of onion juice in sodium hydroxide get vanished., II. Odour of onion juice in dilute hydrochloric acid remained same., III. Onion acts as olfactory indicator., IV. The smell of onion was unpleasant., (a) I and II, (b) I and III, (c) III and IV, (d) I, II and III

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145, , CBSE Sample Paper Science Class X (Term I), , 30. A coating on zinc will be observed in, , Iron, sulphate, I, , Zn, , Copper, sulphate, , Zinc, sulphate, II, , Zn, , (a) I and III, (c) Only II, , III, , Zn, , Aluminium, sulphate, IV, , Zn, , (b) Only I, (d) III and IV, , Direction (Q. No. 31 to 34) Consist of two statements – Assertion (A) and Reason (R). Answer these, questions selecting the appropriate option given below :, (a) Both A and R are true and R is the correct explanation of A., (b) Both A and R are true, but R is not the correct explanation of A., (c) A is true, but R is false., (d) A is false, but R is true., , 31. Assertion Zn + 2HCl ¾® ZnCl 2 + H 2, This reaction is an example of displacement reaction., Reason Zinc being more reactive than hydrogen, can displace hydrogen from its, solution., , 32. Assertion Weak acids have low electrical conductivity., Reason The concentration of hydrogen ions is equal in strong acids and weak acids., , 33. Assertion Translocation of solutes takes place across the phloem., Reason Solutes can be translocated both in upward and downward directions., , 34. Assertion The height of an object is always considered positive., Reason An object is always placed above the principal axis in upward direction., , 35. Four students studied reactions of zinc and sodium carbonate with dilute hydrochloric, acid and dilute sodium hydroxide solutions and they presented their results as follows., The ’3’ represents evolution of gas whereas ‘O’ represents absence of any reaction., Zn Na2CO3, HCl, P, P, O, NaOH, P, I, Zn Na2CO3, O, O, HCl, HCl, NaOH P, NaOH, P, III, , HCl, NaOH, , Zn Na2CO3, O, P, O, P, II, Zn Na2CO3, P, P, O, O, IV, , (d) IV, , 36. The heart pump blood to transport oxygen from lungs to various body parts. Which, sequence is the correct path for the flow of blood?, (a) Right atrium ® right ventricle ® aorta, (b) Right atrium ® aorta ® right ventricle, (c) Left atrium ® aorta ® right ventricle, (d) Left atrium ® left ventricle ® aorta, , SAMPLE PAPER 5, , The right set of observations is given by student, (a) I, (b) II, (c) III

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146, , CBSE Sample Paper Science Class X (Term I), , 37. Choose the function of the pancreatic juice from the following, (a) Trypsin digest proteins and lipase digest carbohydrates, (b) Trypsin and lipase digest fats, (c) Trypsin digest proteins and lipase emulsified fats, (d) Trypsin and lipase digest proteins, , 38. Which of the following statement is not true about respiration?, (a) The gaseous exchange takes place in alveoli, (b) Carbon dioxide is more soluble in water than oxygen, (c) In humans, the respiratory pigment is lymph, (d) Rings of cartilage are present in the throat to ensure that the air passage does not collapse, , 39. A doctor has prescribed a corrective lens of power + 1.5 D. Find the focal length of this, lens., (a) 1.5 m, , (b) 0.67 m, , (c) 15 m, , (d) 2.3 m, , 40. The refractive indices of four media P, Q, R and S are given in the following table:, Medium, Refractive index, , A, , B, , C, , D, , 1.33, , 1.50, , 1.52, , 2.40, , If light travels from one medium to another medium, then which one of the following, is true?, (a) Speed of light in medium D is more than speed of light in medium C., (b) Medium B is the rarest medium., (c) Speed of light remains same in all mediums, (d) Medium A is the rarest medium., , 41. The liquid waste product of plants formed due to oxidation of various essential oil is, (a) gums, , (b) latex, , (c) resins, , (d) tannin, , 42. What will happen if the undigested food is kept too long in our large intestine?, (a) The undigested food will become dry and hard, (b) The undigested food will be completely digested, (c) The undigested food will get absorbed by the wall of large intestine, (d) The undigested food will get stuck in the large intestine, , 43. A ray of light falls on one face of an equilateral glass prism at 40° and emerges from the, other face at the same angle. The deviation suffered by the ray is, (a) 60°, (b) 40°, (c) 20°, (d) 90°, , 44. In case of normal incidence, what would be the angle of deviation through a glass slab?, , SAMPLE PAPER 5, , (a) Maximum, , (b) Minimum, , 45., , (c) 90°, , (d) 0°, , 50 cm, , F, , P, 20 cm, , Screen, , Examine the above diagram. At what range of distances should a candle flame be held, from the mirror to obtain its real image on the screen?, (a) 0-20 cm, (b) 20-40 cm, (c) 40 cm, (d) 50 cm

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147, , CBSE Sample Paper Science Class X (Term I), , 46., Incident, ray, , 45º, , 45º, , The minimum refractive index of the prism given above for total internal reflection, should be, 3, 3, (a), (c) 3, (d), (b) 2, 2, 2, , 47., , A, F2, 2F1 B, , F1 O, , B', 2F2, , A', , The above lens has a focal length of 50 cm. The object of height 10 mm is placed at a, distance of 60 cm from the pole of lens. Find the height of the image., (a) - 5 cm, (b) - 30 cm, (c) 5 cm, (d) - 6 cm, , 48., , Element, , Lustre, , Hardness, , Heat conductivity, , A, , No, , Soft, , Poor, , B, , Yes, , Soft, , Good, , C, , Yes, , Hard, , Good, , D, , Yes, , Hard, , Poor, , Which of the above elements can be used for making utensils?, (a) C and D, , (b) A and B, , (c) Only B, , (d) Only C, , Section C, This Section C consists of three Cases followed by questions. There are a total of 12 questions in this section., Attempt any 10 questions from this section. The first attempted 10 questions would be evaluated., Case I. Two test tubes are taken with different solutions, copper sulphate and iron sulphate solution., Observe the two test tubes A and B in the diagram given below and answer the following questions., Cork, Thread, Iron nail, , Copper wire, , Copper, sulphate, solution, , Iron sulphate solution, , A, Test tube, , B, Test tube, , 49. Which type of reaction is involved in test tube A?, (a) Decomposition, (c) Displacement, , (b) Combination, (d) Neutralisation, , SAMPLE PAPER 5, , Test tube stand

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148, , CBSE Sample Paper Science Class X (Term I), , 50. Which of the following is the balanced equation with correct physical states occurs in, test tube A?, (a) Fe ( s) + CuSO 4 ( aq) ¾® FeSO 4 ( aq) + Cu( s), (b) 2Fe ( s) + 2CuSO 4 ( l) ¾® 2 FeSO 4 ( s) + Cu( s), (c) 4Fe ( s) + 3CuSO 4 ( aq) ¾® 4Fe 2 O 3 ( s) + 3CuS ( s), (d) 2Fe ( s) + 2CuSO 4 ( aq) ¾® 2 FeSO 4 ( s) + 2Cu ( s), , 51. In test tube B, which of the following statement is correct ?, (a) Copper will displace iron from its sulphate solution, (b) The colour of the solution will change, (c) The temperature of solution will increase, (d) No reaction take place, , 52. What will be the change in colour in test tube A ?, (a) Green ® Colourless, (c) Blue ® Dark brown, , (b) Blue ® Light green, (d) Brown ® Colourless, , Case II. Human heart acts like a pumping machine in body that pushes out the blood into the blood, vessels. It is situated between the lungs slightly towards the left side of the chest. Human heart is, four-chambered. These chambers are meant to prevent mixing of oxygenated and deoxygenated blood., The diagram given below is the longitudinal section of human heart., E, , C, , D, , F, , A, , B, , 53. Part A and part B are separated by, (a) valves, (c) capillaries, , (b) interventicular septum, (d) muscles, , 54. Right atrium receives blood from, (a) pulmonary aorta, (b) pulmonary veins, (c) inferior vena cava and superior vena cava (d) pulmonary artery, , SAMPLE PAPER 5, , 55. What is the function of part D ?, (a) It receives oxygen rich blood from right ventricle and circulates it to various body parts, (b) It receives carbon dioxide rich blood from lungs and circulates it to heart, (c) It receives oxygen rich blood from the left ventricle and circulates it to various body parts, (d) It receives oxygen rich blood from the left ventricle and circulates it to the lungs, , 56. What is the difference in the composition of blood in parts C and F?, (i) C—Pulmonary artery, having deoxygenated blood, (ii) F–Pulmonary veins, having deoxygenated blood, (iii) C—Aorta, having oxygenated blood, (iv) F—Pulmonary veins, having oxygenated blood, Choose the correct option., (a) (i) and (ii), (b) (ii) and (iii), (c) (iii) and (iv), , (d) (i) and (iv)

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149, , CBSE Sample Paper Science Class X (Term I), , Case III. Raman wanted to know about the uses of convex mirror. On learning, he understood that a, convex mirror is also a simple way of improving the safety in our warehouse or production, environment. In a work environment or warehouse, convex mirrors can be placed at crossing or blind, spots to enable workers to see approaching for lifts, other vehicles or approaching colleagues. This, provides employees with the necessary overview of their work environment and therefore, increases the, safety in the workplace., , 57. When Raman tries to move object away from the convex mirror, he noticed that the, size of image, (a) increases with distance, (b) decreases with distance, (c) does not change, (d) is same but brightness decreases, , 58. The image formed by a convex mirror of focal length 30 cm is one-quarter of the object., Select the row containing the correct value of object and image distance., (a), (b), (c), (d), , Object distance ( u) (in cm), - 90, - 22.5, - 90, - 90, , Image distance ( v) (in cm), + 22.5, - 90, - 22.5, + 90, , 59. His friend noted some properties of convex mirror with this demonstration., I. Convex mirror always forms a virtual and erect image., II. Convex mirror may form real or virtual image depending upon the position of object., III. Convex mirrors provide wide field of view as they are curved outwards., , 60. An object of 7 cm in length is placed at a distance of 20 cm in front of a convex mirror, of radius of curvature 30 cm. The size and position of image formed are respectively, 60, cm, 7, 7, (c) + 3 cm, +, cm, 60, (a) - 3 cm, +, , 60, cm, 7, 7, (d) - 3 cm, +, cm, 60, , (b) + 3 cm, +, , SAMPLE PAPER 5, , Which of the above mentioned properties, a convex mirror has due to which it is used, as rear view mirror?, (a) I and III, (b) II and III, (c) I and II, (c) I, II and III

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OMR SHEET, , SP 5, , Roll No., Sub Code., , Student Name, , Instructions, Use black or blue ball point pens and avoid Gel & Fountain pens for filling the OMR sheet., Darken the bubbles completely. Don’t put a tick mark or a cross mark, half-filled or over-filled bubbles will not be read, by the software., Correct, , ✔, , ✗, , Incorrect, , Incorrect, , Incorrect, , Do not write anything on the OMR Sheet., Multiple markings are invalid., , 1, , 21, , 41, , 2, , 22, , 42, , 3, , 23, , 43, , 4, , 24, , 44, , 5, , 25, , 45, , 6, , 26, , 46, , 7, , 27, , 47, , 8, , 28, , 48, , 9, , 29, , 49, , 10, , 30, , 50, , 11, , 31, , 51, , 12, , 32, , 52, , 13, , 33, , 53, , 14, , 34, , 54, , 15, , 35, , 55, , 16, , 36, , 56, , 17, , 37, , 57, , 18, , 38, , 58, , 19, , 39, , 59, , 20, , 40, , 60, , Check Your Performance, Total Questions:, Total Correct Questions:, , If Your Score is, , Score Percentage =, , Total Correct Questions, Total Questions, , × 100, , Less than 60%, > Average (Revise the concepts again), Greater than 60% but less than 75% > Good (Do more practice), Above 75%, > Excellent (Keep it on)

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151, , CBSE Sample Paper Science Class X (Term I), , Answers, 1. (a), 11. (d), 21. (c), , 2. (b), 12. (b), 22. (a), , 3. (a), 13. (b), 23. (d), , 4. (d), 14. (d), 24. (b), , 5. (c), 15. (b), 25. (c), , 6. (b), 16. (c), 26. (a), , 7. (b), 17. (d), 27. (a), , 8. (b), 18. (a), 28. (b), , 9. (a), 19. (b), 29. (d), , 10. (b), 20. (a), 30. (a), , 31. (a), 41. (c), 51. (d), , 32. (c), 42. (a), 52. (b), , 33. (b), 43. (c), 53. (b), , 34. (a), 44. (d), 54. (c), , 35. (a), 45. (b), 55. (c), , 36. (d), 46. (b), 56. (d), , 37. (c), 47. (a), 57. (b), , 38. (c), 48. (d), 58. (a), , 39. (b), 49. (c), 59. (a), , 40. (d), 50. (a), 60. (b), , EXPLANATIONS, 1. Gas is evolved vigorously in both beakers., In beaker I,, 2HCl + Zn ¾® ZnCl2 + H2 ­, In beaker II, 2NaOH + Zn ¾® Na 2ZnO2 + H2 ­, 2. When calcium oxide is treated with water, then, calcium hydroxide is produced along with heat., CaO + H2O ¾® Ca(OH)2 + Heat, So, this reaction released heat, hence it is, exothermic., 3. When metal oxide is reacted with acid, it forms, salt and water., e.g. CuO + 2HCl ¾® CuCl2 + H2O, Fe2O3 + 6HCl ¾® 2FeCl3 + 3H2O, MgO + 2HCl ¾® MgCl2 + H2O, ZnO + 2HCl ¾® ZnCl2 + H2O, There is no evolution of gas., Hence, option (a) is correct., 4. When lead tetraoxide is heated, then lead, oxide and oxygen gas produced. This lead, oxide is yellow in colour., D, 2Pb 3 O4, ¾¾, ® 6PbO + O2, Lead oxide, (yellow), , Lead tetraoxide, , 5. Basic solutions have pH > 7. So, C represents, the highly basic area in the given graph., 6., , Reduction, , 3Fe + 4H2O, , Fe3O4 + 4H2, , Oxidation, , 7. Zinc reacts with dil. HCl and produces zinc, chloride and hydrogen gas., Zn + 2 HCl ¾® ZnCl 2 + H 2, (dil.), , The surface of Zn metal become dull because, of reaction with HCl to form zinc chloride., , (Parent acid), , (Parent base), , 9. In chlor-alkali process, the reaction involved, Electric current, , 2NaCl + 2 H 2O ¾¾¾¾¾¾®, 2 NaOH + Cl 2( g ) + H 2( g ), So, the products formed from this process are, NaOH, Cl 2 and H 2., 10. The reaction between CaO and water is, exothermic in nature., Hence, change in temperature take place in the, mixture and the container gets hot as heat is, released during the reaction., 11. The correct labelling is, W = Larynx, X = Trachea, Y = Bronchioles, Z = Bronchus, Bronchus are main passage way into the lungs., It further get divided into smaller bronchioles., The incorrect option can be correct as :, X–Trachea : It serve as a passage of air, Y –Bronchiole : It deliver air to the alveoli, W–Larynx : It serves as a chamber for, respiratory functions., 12. The correct labelling is, 1-Stomach, 2-Pancreas, 3-Small intestine,, 4-Large intestine, 5-Liver, 6-Mouth, Stomach secretes pepsin, salivary glands in, mouth secretes salivary amylase, pancreas, secretes trypsin and lipase and small intestine, secretes lipase, peptidase, etc., 13. In the stem of woody plants, the exchange of, respiratory gases takes place through small, pores called lenticels whereas in herbaceous, plants, stomata found on the stem helps in, exchange of respiratory gases., , SAMPLE PAPER 5, , The substance which is reduced is H 2O because, after the removal of oxygen atom, it becomes, H 2. Since, H 2O gets reduced into H2, it will, acts as an oxidising agent also because the, substance which gets reduced is also known, as oxidising agent., , 8. Ammonium sulphate is obtained from, ammonium hydroxide (parent base) and, sulphuric acid (a parent acid)., H2SO4 + 2NH4OH ¾® (NH4 )2 SO4 + 2H2O

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152, , CBSE Sample Paper Science Class X (Term I), , 14. Egg white contains only protein and no fat., The digestion of proteins occur in stomach and, proteins are converted into amino acids. So,, amino acids will be found leaving the stomach., The absorption of amino acids occurs in small, intestine. So, only water will be found leaving, the small intestine., 15. Amoeba takes in food using temporary, finger-like extensions of the cell surface, which fuse over the food particle forming a, food vacoule., 16. The correct labelling is, A-Right ventricle, B-Right atrium, C-Left atrium, D-Left ventricle, The right atrium receives the deoxygenated, blood from the different body parts. The right, ventricle transport deoxygenated blood to the, lungs., The left atrium receives the oxygenated blood, from lungs which then enter left ventricle and, transported to various body parts., 17. In foggy weather, light is scattered by the tiny, water droplets present in air. So, the person, who is travelling in day time in foggy weather, is not able to see things clearly because very, less amount of light is entering into his eyes., 18. When white light passes through a prism, it, gets dispersed as shown in the figure below., , White, light, , Red, Violet, , 21. When the image is sharp, it is at focus; slightly, blurred larger image is beyond focus, and, slightly blurred smaller image is before focus., \, f3 < f1 < f2, 22. The correct diagram among the given, diagrams of mirror is shown, F, , P, , C, , 23. To form an erect and magnified image, an, object must be placed between the optical, centre and focus of given convex lens., So d should be less than 20 cm., As f = 20 cm, hence distance of object from the, lens is d < 20 cm., 24. When a ray of light incident on a refractive, surface, then it emerges out to be parallel with, the incident ray but displaced laterally. So, ray, NQ is the correct emergent ray., D, 25. Pb3O 4 ( s) ¾¾, ® PbO( s) + O 2( g ), , This is an endothermic reaction because to, carry out this reaction, Pb 3O4 is heated and, oxygen gas is evolved., Thus, option (c) is correct., 26. Higher the pH value, lower the concentration, of H + ions., So, in solution A, the concentration of H + ions, is lowest. Hence, the pH value will be higher in, solution ‘A’., 27. When ferrous sulphate is heated, it produces, ferric oxide and sulphur dioxide and sulphur, trioxide gases., D, D, FeSO 4 × 7 H 2O ( s) ¾¾, ® FeSO 4 ( s) ¾¾, ®, - 7H 2O, , Fe2O 3( s) + SO 2( g ) + SO 3( g ), , SAMPLE PAPER 5, , Red light is least scattered and hence, it, deviates less than the violet and blue., 19. Only a concave mirror can have a, magnification greater than one. Hence, the, given mirror is a concave mirror., 20. When a convex lens is immersed in a liquid of, refractive index greater than the refractive, index of glass, then it will act like a diverging, lens., Because by the definition, concave lens, is a, rarer medium surrounded by two surfaces of, denser medium., , The gases produced are toxic in nature., Hence, to avoid inhaling toxic gases, IV is, correct position to observe the reaction., 28. The decreasing reactivity order of metals is, Al > Zn > Fe > Cu., From the results given in the table, Al is the, most reactive among others because it shows, displacement reactions in three solution, Zn, shows displacement reaction in two solutions, and iron shows displacement in one solution., The least reactive metal is copper as it does not, react with any solution.

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153, , CBSE Sample Paper Science Class X (Term I), , 29. I, II and III observations are correct. Onion is, an olfactory indicator whose odour changes or, vanished in basic medium and remained, unchanged in acidic medium., , 38. Statement (c) is incorrect and can be corrected as,, In humans, the respiratory pigment is, haemoglobin which has a very high affinity for, oxygen., , 30. Zn, being more reactive than iron and copper,, therefore displaces the iron and copper from, their solutions. Hence, Fe and Cu will form, coating on zinc due to displacement reaction., , 39. Given, power of a corrective lens, P = 1.5 D, 1, We know that, power (P) =, focal length ( f ), 1, 1, \ Focal length, f = =, Þ f = 0.67 m, P 1.5, , 31. Both A and R are true and R is the correct, explanation of A., Zinc being more reactive than hydrogen,, displaces it from its solution (i.e. HCl) and, form ZnCl2., 32. A is true but R is false., Weak acids have low electrical conductivity, due to partial dissociation in aqueous medium., They produce less number of ions., The concentration of H + ions is more in strong, acids and less in weak acids., 33. Both A and R are true, but R is not the correct, explanation of A., Translocation of solutes is the movement of, organic food or solute in soluble form from one, part to another part of plant., Translocation of solutes take place across the, phloem. Solutes can be translocated both in, upward and downward directions due to end, to end arrangement of sieve tubes., 34. Both A and R are correct and R is the correct, explanation of A. The distance above the, principal axis is always considered as positive., Hence, the height of an object is always, positive., 35. The reactions of Zn and Na 2CO3 with acids, and bases are as follows:, Zn + 2 HCl ¾® ZnCl 3 + H 2, Zn + 2 NaOH ¾® Na 2ZnO 2 + H 2, Na 2CO 3 + 2 HCl ¾® 2 NaCl + CO 2 + H 2O, , 36. The correct sequence for the transportation of, blood from lungs to various body parts is, Lungs ® Pulmonary vein ® Left atrium, Various body parts ¬ Aorta ¬ Left ventricle, 37. Pancreas secretes pancreatic juice which, contains digestive enzymes like lipase and, trypsin. Trypsin digests the proteins and lipase, breaks down the emulsified fats., , 41. The liquid waste product of plants formed due, to oxidation of various essential oil is resins, that protects the plants from insects and, pathogens., 42. The undigested food enters the large intestine, from the small intestine where reabsorption of, water occurs. If the undigested food is kept too, long in our large intestine then the undigested, food will become more dry and hard., 43. As, ÐD + ÐA = Ði + Ðe, Þ, , ÐD = Ði + Ðe - ÐA, = 40° + 40° - 60°, , [QÐi = Ðe = 40°, ÐA = 60°], Þ, , ÐD = 20°, , 44. In case of normal incidence,, Ði = 0, \, Ðr = 0, i.e. there is no refraction and hence, no deviation., 45. Here, f = - 20 cm and v = - 50 cm, The image must be real, inverted and beyond, C. Therefore, the object must lie between F and, C, i.e. between 20 cm to 40 cm., 46. The path of ray can be shown as, A, Incident, ray, , 45º, 45º, , r, , 45º, B, , C, , Here, i = 45°, For minimum refractive index, the light should, be just totally internally reflected., \, r = 90°, , SAMPLE PAPER 5, , Na 2CO 3 + NaOH ¾® No reaction, Hence, student I has given the correct set of, observation., , 40. As refractive index of medium A is smaller, among others, so it is the rarest medium, hence, the speed of light in medium A is fastest., Frequency does not change with change in, refractive index.

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154, , CBSE Sample Paper Science Class X (Term I), , Using Snell’s law,, m sin 45° = sin 90°, 1, m=, = 2, \, 1, 2, 47. Given,, , f = 50 cm, u = - 60 cm,, , ho = 10 mm = 1 cm, Using lens formula,, 1 1 1, - =, v u f, 1 1 1, 1, 1, Þ, = + =, v, f u 50 60, 1 6-5, 1, Þ, =, =, v, 300, 300, Þ, v = + 300 cm, h, v, \Magnification, m = i =, ho u, hi, 300, Þ, =, 1 - 60, Þ, , hi = - 5 cm, , 48. For making utensils, element should be hard,, good conductor of heat and lustrous. So, these, properties are only present in element C., 49. In test tube A,, Fe( s) + CuSO 4 ( aq) ¾® FeSO 4 ( aq) + Cu( s), The reaction involved is displacement reaction, as copper is displaced by iron from its sulphate, solution., 50. Fe ( s ) + CuSO 4 ( aq ) ¾® FeSO 4 ( aq) + Cu ( s ), is the balanced chemical equation as the total, number of atoms of each elements are equal on, both sides of the equation. Hence, it is a, balanced reaction with correct physical states, of the chemicals., , SAMPLE PAPER 5, , 51. As iron is more reactive than copper, copper, will not displace iron from its sulphate, solution and hence, there will be no reaction., 52. Copper sulphate solution is blue in colour, but, after the displacement reaction take place, the, ferrous sulphate solution forms which is light, green in colour., 53. Interventricular septum separates part A (right, ventricle) and part B (left ventricle)., 54. Right atrium receives blood from superior and, inferior vena cava., , Superior vena cava brings deoxygenated blood, from upper part of the body, while inferior, vena cava bring blood from lower parts of the, body into the right atrium of the heart., 55. The blood vessel D (aorta) receives oxygen rich, blood from the left ventricle and circulates it to, different parts of the body., 56. The blood vessel C (pulmonary artery) has got, deoxygenated blood, while the blood vessel F, (pulmonary vein) has oxygenated blood., 57. When the object is moved away from the, convex mirror, the image moves closer to the, focus till it becomes a point sized image., Thus, size of the image decreases with, distance., 1, 58. Given, f = + 30 cm, m =, 4, v 1, Q m = - = or u = - 4 v, u 4, Using mirror formula,, 1 1 1, = +, f v u, 1 1, 1, 3, = =, Þ, f v 4v 4v, 3 f 3 ´ 30, or v =, =, = 22.5 cm and u= - 90 cm, 4, 4, 59. Convex mirrors are used as rear view mirrors, in cars because they always form virtual and, erect image and provide a wider field of view, as they are curved outwards., 30, 60. Given, h1 = 7 cm, u = - 20 cm, f =, = 15 cm, 2, Using mirror formula,, 1 1 1, = +, f v u, 1 1 1, Þ, = v, f u, 1, 1 æ 1 ö 4 +3 7, Þ, =, -ç, =, ÷=, v 15 è -20 ø, 60, 60, 60, or, cm, v=+, 7, -v, h, \ Magnification, m = 2 =, h1, u, 60, h2, 7 =3, Þ, =, 7, -20 7, Þ, h2 = + 3 cm

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SAMPLE PAPER 6, SCIENCE, A Highly Simulated Practice Questions Paper, for CBSE Class X (Term I) Examination, , Instructions, (i) This paper is divided into three Sections:, (a) Section A – Contains 24 questions. Attempt any 20 questions., (b) Section B – Contains 24 questions. Attempt any 20 questions., (c) Section C – Contains 12 questions. Attempt any 10 questions., (ii) Each questions carries 0.80 mark., (iii) There is NO negative marking., Maximum Marks : 40, Time allowed : 90 Min., , Roll No., , Section A, Section-A consists of 24 questions. Attempt any 20 questions from this section. The first attempted 20, questions would be evaluated., , 1. A student used the following reaction for the preparation of oxygen gas in laboratory :, Heat, , 2KClO3 ( s) ¾¾¾® 2KCl ( s) + 3O 2 ( g), Catalyst, , What would he observe about the reaction?, (a) The reaction is endothermic and a type of decomposition reaction., (b) It is a decomposition reaction and exothermic in nature., (c) It is a photochemical decomposition reaction and exothermic in nature., (d) It is a displacement reaction., , 2. Identify the colour change in hydrated copper sulphate crystals in the given experiment., , Removing water of crystallisation, ., , (a) Blue to green, , (b) Blue to white, , (c) Blue to colourless, , (d) Blue to black

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156, , CBSE Sample Paper Science Class X (Term I), , 3., Iron, Steam, , Iron (II), (III) oxide, , Gas, , Which of the following combination are correct about the acidic nature of oxide of iron and, gas?, Acidic, , Gas evolved, , (a), , Yes, , No, , (b), , No, , Yes, , (c), , Yes, , Yes, , (d), , No, , No, , 4. Identify the balanced equation from the following., (a) 2K( s) + H2 O( l) ¾® KOH( aq) + H 2 ( g), (b) K( s) + 2H2 O( l) ¾® KOH( aq) + 2H 2 ( g), (c) 2K( s) + 2H2 O( l) ¾® 2KOH( aq) + H 2 ( g), (d) K( s) + H2 O( l) ¾® KOH( aq) + H 2 ( g), , 5. The graph given below depicts a neutralisation reaction,, (HCl + NaOH ¾® NaCl + H 2O)., , The pH of solution changes as we add excess of acid to an alkali., A, , 14, , B, 7, pH, , C, D, 0, , Volume of acid added, , Which letter denotes the area of the graph where formation of NaCl observed?, (b) B, (d) D, , (a) A, (c) C, , 6. In the reaction of iron with water,, , SAMPLE PAPER 6, , 3Fe( s) + 4H 2O( g) ¾® Fe 3O 4 ( s) + 4H 2 ( g), Which option in the given table correctly represents the substance oxidised and, reducing agent?, Substance oxidised, (a) Fe, (b) H2 O, (c) Fe3 O4, (d) H 2, , Reducing agent, Fe, H2, Fe, H2 O

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157, , CBSE Sample Paper Science Class X (Term I), , 7. The chemical reaciton between copper oxide and hydrogen can be categorised as :, (a) double displacement reaction, (b) combination reaction, (c) redox reaction, (d) exothermic reaction, , 8. Which of the given option correctly represents the parent acid and parent base of, ammonium carbonate?, Parent acid, Parent base, (a) NH 3, H2 CO3, (b) H2 CO3, NH4 OH, (c) H2 CO3, NH 3, (d) HNO 3, Na 2 CO3, , 9. How will you identify that the reaction occurs between potassium iodide and lead, nitrate solution?, (a) By checking its temperature., (b) By formation of white precipitate., (c) By the formation of yellow insoluble precipitate., (d) By stirring., , 10. What will be correct statement regarding universal indicator?, (a) It is an indicator having pH = 7, (b) It gives orange colour at pH = 3, (c) It gives blue colour at pH = 5, (d) It becomes colourless at pH = 7, , 11. Carefully study the diagram of the cross-seciton of leaf with label (i), (ii), (iii) and (iv)., Select the option which gives correct identification and main function and/or, characteristics., Midrib, , Lamina or, leaf blade, Veinlet, , Phloem Xylem, Vascular bundle, , (iii), (iv), , (i ), Air spaces, , Stomatal pore, , Lower, epidermis, , (a) (i) Chloroplast – are present in the mesophyll cells of green plants, (b) (ii) Guard cells – controls the exchange of gases, (c) (iii) Waxy cuticle – helps in photosynthesis, (d) (iv) Upper epidermis – It contains millions of stomata and regulate gas exchange, , SAMPLE PAPER 6, , (ii)

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158, , CBSE Sample Paper Science Class X (Term I), , 12. Identify the option that indicate the parts that carry deoxygenated blood., (iii), (i ), , (ii), , (a) (i) Right atrium, (ii) pulmonary arteries, (iii) Vena cava, (b) (i) Right atrium, (ii) Vena cava, (iii) Pulmonary arteries, (c) (i) Vena cava, (ii) Pulmonary vein, (iii) Plumonary ateries, (d) (i) Right atrium, (ii) vena cava, (iii) Pulmonary veins, , 13. Which of the following is a protein digesting enzyme?, (a) Pepsin, (b) Bile, (c) Lipase, (d) Salivary amylase, , 14. The figure given below shows a human digestive system with labels (i) to (iv). Identify, the correct label with its function., Mouth/Buccal cavity, Salivary glands, , (i), , Tongue, (ii), Liver, Small, intestine, , Diaphragm, , Gall bladder, (stores bile), , (iv), , (iii), , SAMPLE PAPER 6, , Rectum, Appendix, Anus, , (a) (i) Oesophagus – ensures swift movement of food by way of rhythmic relaxation and, contraciton of muscles, (b) (ii) Stomach – secretes HCl that helps in emulsification of fats, (c) (iii) Pancreas – secretes acidic pancreatic juice containing enzymes, (d) (iv) Large intestine – secretes trypsin for the digestion of proteins

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159, , CBSE Sample Paper Science Class X (Term I), , 15. The given diagram represents the process of transpiration taking place in plants., Arrows indicates movement of water during transpiration. Which of the following, statement is correct regarding of transpiration :, , (a) Evaporation of water molecules creates suction which provide water to the roots., (b) Transpiration occurs mainly with the half of xylem present in leaves., (c) Transpiration cause water to rise in plants by pulling it upwards., (d) The effect of root pressure in transport of water is more important during daytime., , 16. Observe the diagram of human excretory system., , (A ), (B), , (D), , (C), , Match the labelling in Column I and correlate with the function in Column II., Column I, , Column II, , A, , 1. It stores urine until it is passed out., , B, , 2. It allows urine to pass outside the body., , C, , 3. It is involved in the formation of urine., , D, , 4. It collects urine from the kidney., , C, 4, 2, , D, 2, 1, , A, (b) 2, (d) 3, , B, 3, 4, , C, 4, 1, , D, 1, 2, , 17. The depth of a bucket filled with water seems to be less than its actual depth. Which, phenomena is responsible for this?, (a) Reflection of light by surface of water, (b) Scattering of light by water molecules, (c) Refraction of light at the interface, (d) Dispersion of light by surface water molecules, , SAMPLE PAPER 6, , Codes, A, B, (a) 3, 1, (c) 3, 4

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160, , CBSE Sample Paper Science Class X (Term I), , 18. Which diagram shows image formation of an object on a screen by a diverging mirror?, , (a), , Object, , (b), , Object, F, , F, , (c), , Object, , (d), , Object, , F, , F, , 19. Both a spherical mirror and a thin spherical lens have a focal length of - 15 cm. What, type of mirror and lens they are there?, (a) Concave mirror and convex lens, (c) Convex mirror and convex lens, , (b) Concave mirror and concave lens, (d) Convex mirror and concave lens, , 20. If a beam of red light, yellow light and violet light are incident at the same angle on the, inclined surface of a prism from air and produce angle of deviation r, y and v, respectively, which of the following is correct?, (a) r < y < v, (b) v < r < y, (c) v < y < r, (d) y < r < v, , 21. A concave mirror produces a magnification of +2. The object is placed, (a) at focus of mirror, (b) between focus and centre of curvature, (c) between focus and pole, (d) beyond centre of curvature, , 22., , SAMPLE PAPER 6, , O, , Examine the above figure and state which of the following option is correct?, [one small box in the figure = 1 cm], (a) The magnification of image is +1 and image is +3 cm from mirror., (b) The magnification of image is -1 and image is -3 cm from mirror, (c) The magnification of image is -1 and image is +3 cm from mirror, (d) The magnification of image is +1 and image is -3 cm from mirror., , 23. Diamond sparkles more than a similar cut glass piece. It is because, (a) more cuts are present on diamond than that on glass piece., (b) more internal reflection takes places due to greater refractive index of diamond., (c) dispersion of light is shown by diamond., (d) scattering occurs in diamond.

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161, , CBSE Sample Paper Science Class X (Term I), , 24. Two identical prisms P1 and P2 are used to study the recombination of white light., What is the correct position of prisms, so that a narrow beam of white light incident on, one prism ( P1 ) emerges out from the second prism ( P2 ) as white light?, White, light, , White, light, , White, light, , White, light, , (i), , (iv), , (iii), , (ii), , (a) (i), (c) (iii), , (b) (ii), (d) (iv), , Section B, This section consists of 24 multiple choice questions with overall choice to attempt any 20 questions. In case, more than desirable number of questions are attempted, ONLY first 20 will be considered for evaluation., D, , 25. Sodium carbonate ¾¾¾® Na 2O + X, Identify the correct option from the given table which represents the type of reaction and gas, evolved in the reaction., Exothermic, , Gas evolved, , (a), , ✔, , ✕, , (b), , ✕, , ✔, , (c), , ✕, , ✕, , (d), , ✔, , ✔, , 26. In which country is the concentration of hydrogen ion is the highest?, , pH, value, , O, , (a) A, , A, , B, , (b) C, , C, D, Countries, , (c) D, , E, , (d) E, , 27. When metal (M) is treated with diluted H 2SO 4 , then the gas is evolved and is collected, over the water as shown in figure., , (b) The evolved gas is lighter than air., (d) Both (a) and (b), , SAMPLE PAPER 6, , Identify the correct conclusion drawn., (a) The gas evolved is hydrogen., (c) The evolved gas is SO 2 .

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162, , CBSE Sample Paper Science Class X (Term I), , 28. A boy met with an accident and his leg get fractured. He went to the doctor and the, doctor mixed a white powder in water and applied it on his leg along with cotton and, gauze. Which of the following statement is true about white powder?, (I) White powder is Plaster of Paris., (II) On mixing the white powder and water, gypsum is formed., (III) White powder is also used to ornate designs on walls and ceiling., (IV) It gives off CO 2 on mixing with water., Choose the correct option., (a) II and III, (b) I, II and III, (c) III and IV, (d) I and IV, , 29. The table shown below gives information about four metals: A, B, C and D and these, metals are treated with water, steam and dil. HCl. The results are given below., Metals, , Reaction with water, , Reaction with steam Reaction with dil. HCl, , A, , No, , Yes, , Yes, , B, , No, , No, , Yes, , C, , Yes, , Yes, , Yes, , D, , No, , No, , No, , The metal A would be, (a) Fe, (b) Cu, , (c) K, , (d) Ag, , 30. On mixing aqueous solutions of sodium sulphate and barium chloride, the correct, observation is shown in test tube., , ppt, ppt, , Clear, solution, , ppt, , SAMPLE PAPER 6, , I, , II, , III, , IV, , (a) I, (b) II, (c) III, (d) IV, Direction (Q. Nos. 31-34) For given questions two statements are given-one labelled Assertion (A) and, the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and, (d) as given below., (a) Both A and R are true and R is the correct explanation of A., (b) Both A and R are true, but R is not the correct explanation of A., (c) A is true, but R is false., (d) A is false, but R is true., , 31. Assertion Iron articles are painted to prevent rusting., Reason Rusting damages the iron articles and form a reddish-brown layer on them., , 32. Assertion The bleaching powder is basic in nature., Reason Bleaching powder is used as an oxidising agent in chemical industries., , 33. Assertion Lungs always contain a residual volume of air., Reason It is to ensure enough time for the release of CO 2 and for the absorption of O 2 .

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163, , CBSE Sample Paper Science Class X (Term I), , 34. Assertion The Sun is visible to us about 2 minutes before the actual sunrise and about, 2 minutes after the actual sunset., Reason The time difference between actual sunrise and apparent sunrise is about, 2 minutes., , 35. The table given below shows the colour change of indicator in acidic and basic, medium. Which of the following information is incorrect?, Indicators, , Colour change in acid, , Colour change in base, , (i), , Blue litmus paper, , ✕, , ✔, , (ii), , Turmeric, , ✔, , ✕, , (iii), , Methyl orange, , ✔, , ✔, , (iv), , Phenolphthalein, , ✕, , ✔, , Choose the correct option., (a) (i) and (ii), (b) (ii) and (iii), , (c) (iii) and (iv), , (d) (ii) and (iv), , 36. Which of the following substances are produced by anaerobic respiration in yeast?, (a) Carbon dioxide, lactic acid and water, (c) Lactic acid and water, , (b) Carbon dioxide and alcohol, (d) Alcohol and water, , 37. Which process occurring in human body does not involve energy from respiration?, (a) Contraction of heart muscle, (b) Diffusion of oxygen from the alveoli into the blood, (c) Digestion of bread, (d) Maintaining a constant body temperature, , 38. Which of the following statement is true about respiration?, (a) During inhalation, ribs move inward and diaphragm is raised., (b) In the alveoli, exchange of gases takes place, i.e. oxygen from alveolar air diffuses into, blood and carbon dioxide from blood into alveolar air., (c) Haemoglobin has greater affinity for carbon dioxide than oxygen., (d) Alveoli increases surface area for exchange of blood., , 39. If the angle of refraction is 30°. Find the angle of incidence of light ray incident on, surface of a plastic slab of refractive index 3., (a) 30°, (b) 60°, (c) 90°, , (d) 45°, , 40. An object is placed 20 cm in front of a concave mirror of focal length 25 cm. The image, of object will be formed at, (a) 1 ´ 10 2 cm behind the mirror, (c) 2 ´ 10 2 cm in front of mirror, , (b) 1 ´ 10 2 cm in front of mirror, (d) 2 ´ 10 2 cm behind of mirror, , (a) Mushrooms, Cuscuta, bacteria, (c) Cuscuta, ticks, tapeworms, , (b) Ticks, lice, yeasts, (d) Amar-bel, leeches, amoeba, , 42. The function of the lymph fluid is to, (a) drains excess fluid from extracellular space back into the blood, (b) carries digested and absorbed fat from intestine, (c) circulates around the body and help in clotting of blood, (d) Both (a) and (b), , SAMPLE PAPER 6, , 41. Which of the following organisms have a parasitic mode of nutrition?

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164, , CBSE Sample Paper Science Class X (Term I), , 43. If the power of a lens is -10 D, then it means that the lens is a, (a) convex lens of focal length -10 m, (b) concave lens of focal length +10 m, (c) concave lens of focal length -10 cm, (d) convex lens of focal length +10 cm, , 44. If the real image of a candle flame formed by a converging lens is twice the size of, flame and the distance between lens and image is 40 cm. At what distance should the, candle be placed from the lens?, (a) -20 m, (b) 40 cm, (c) 80 cm, (d) -20 cm, , 45., Principal, Axis, , O, , F1, , 2F1, , F2, , 2F2, , A student tried to find out the image formation of above setup, he concluded the, following, (I), (II), (III), (IV), , the image will be formed between focus and optical centre of lens., the image is real., this is a concave lens, hence its focal length is positive., the size of image is very small., , Which one combination of the above statements is correct?, (b) (I) and (IV) are correct, (d) (I), (II), (III) and (IV) are correct, , (a) (II) and (III) are correct, (c) (I), (III) and (IV) are correct, , 46. A graph is drawn between sine of angle of incidence and sine of angle of refraction for, four colours A, B, C and D., C, D, , sin i, , A, B, , sin r, , Which colour have high refractive index?, (a) C, (b) D, , SAMPLE PAPER 6, , 47., , (c) A, , (d) B, , A¢, A, B¢, , F1, , B, , O, , F2, , The above lens has a focal length of 20 cm. The object height is 5 mm which is placed at, a distance of 10 cm from optical centre. The magnification of object is, (a) 1, (b) -2, (c) 2, (d) -1

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165, , CBSE Sample Paper Science Class X (Term I), , 48. The inspection authority visited the cable manufacturing company. They tested their, cable products A, B, C and D, on the basis of their properties., Properties, , A, , B, , C, , D, , Malleable, , Yes, , No, , No, , Yes, , Ductile, , Yes, , No, , No, , Yes, , Electrical conductivity, , No, , Yes, , Yes, , Yes, , Melting point, , High, , Low, , Low, , High, , Which of the following products were disapproved by them?, (a) A, B and C, (b) B, C and D, (c) B and C, (d) C and D, , Section C, This Section C consists of three Cases followed by questions. There are a total of 12 questions in this, section. Attempt any 10 questions from this section. The first attempted 10 questions would be evaluated., , Case I. To check the reaction of acid with zinc, the experiment is performed with zinc granules,, sulphuric acid and soap solution. Some zinc granules are taken in test tube and dilute sulphuric acid is, added to it., The appratus is set as shown below. A burning candle is taken near the soap bubbles filled with gas., Delivery, tube, Stand, , Burning of, gas with a, pop sound, Candle, , Test, tube, Dilute, sulphuric, acid, , Gas, bubbles, Soap bubble, filled with gas, , Zinc, granules, , Soap, solution, , 49. Which gas is produced by the reaction of zinc and dilute sulphuric acid?, (a) H2 S, (c) O 2, , (b) CO 2, (d) H 2, , 50. Which salt is produced in test tube during the experiment?, (b) Zinc sulphate, (d) Zinc carbonate, , 51. Identify the correct chemical equation involved in this experiment., (a) Zn( s) + 2H2 SO4 ( aq) ¾® ZnSO 4 ( s) + H 2 ( g), (b) Zn( s) + H2 SO4 ( aq) ¾® ZnSO 4 ( aq) + H 2 ( g), (c) 2Zn( s) + 2H2 SO4 ( aq) ¾® 2 ZnSO 4 ( aq) + H 2 ( g), (d) 2Zn( s) + 2H2 SO4 ( aq) ¾® 2ZnSO 4 ( s) + H 2 ( g), , SAMPLE PAPER 6, , (a) Zinc hydroxide, (c) Zinc oxide

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166, , CBSE Sample Paper Science Class X (Term I), , 52. What is the role of soap solution in this experiment?, (a) It changes the acidity of gas evolved., (b) It is used for fragrance., (c) It provides medium for bubble formation in which H 2 is trapped in small parts, (d) All of the above, Case II. Rahul was undergoing the treatment for kidney failure. This process is managed by, artificial kidney. It is the process in which nitrogenous wastes are removed from the blood through, dialysis. It contains the number of tubes with a semipermeable lining suspended in a tank filled with a, dialysing fluid., X, , Line from, apparatus, to vein, , Tubing made up of, a selectively, permeable membrane, , Dialysing, solution, , Fresh dialysing, solution, , Y, , 53. The above diagram represents the process of haemodialysis, which is done to remove, (a) extra blood, (b) extra cellular fluid, (c) extra urea, (d) extra water, , 54. Normally in a healthy adult, daily initial filtrate in the kidneys is about, (a) 180 L, (c) 100 L, , (b) 150 L, (d) 250 L, , 55. Which substance have the lowest concentration at X and the highest concentration at Y ?, (a) Glucose concentration is lowest at X and salts concentration is highest at Y., (b) Urea concentration is lowest at X and salts and urea concentration is highest at Y., (c) Water concentration is highest at X and glucose concentration is lowest at Y., (d) Water concentration is lowest at X and glucose concentration is highest at Y., , SAMPLE PAPER 6, , 56. Which of the following statements are incorrect for dialysis ?, I. The fluid has same osmotic pressure as blood except that it is devoid of, nitrogenous waste., II. The waste products from the blood pass into dialysing fluid by osmosis., III. This process is different because there is more reabsorption involved., IV. The actual volume of initial filtrate excreted is only a litre or two a day., Choose the correct option., (a) I and II, (c) II, III and IV, , (b) II and III, (d) Only II

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167, , CBSE Sample Paper Science Class X (Term I), , Case III. Priyanka observed the apparent random wavering or flickering of objects when seen through, a turbulent steam of hot air rising above a fire or a radiator. She noticed that the air just above the fire, becomes hotter than the air further up. She wants to know about this phenomenon. She listed some, similar phenomena based on this effect and tried to know more., , Observes eye, Water, , Burner, , 57. Which phenomena is observed by Priyanka when she saw through a steam of hot air?, (a) Scattering of light, (b) Atmospheric refraction, (c) Tyndall effect, (d) Absorption of light, , 58. She listed some phenomena similar to this, choose the correct one which are present on, the list., (a) Twinkling of stars, advance sunrise and delayed sunset., (b) Tyndall effect and scattering of light., (c) Colour of sun at sunrise and sunset., (d) Formation of rainbow and dispersion., , 59. Her friend is trying to observe the star in sky and concluded the following, (i), (ii), (iii), (iv), , The position of stars changes continuously., Light comes to earth after reflection from earth’s atmosphere., Due to dispersion, different colours of stars are seen from earth., Light suffers refraction from different layers of atmosphere., , Which combination is correct for given statements?, (a) (i) and (ii), (b) (iii) and (iv), (c) (i) and (iv), (d) (ii) and (iv), , 60. Colder layers of air present in atmosphere are considered as, , SAMPLE PAPER 6, , (a) optically rarer medium, (b) optically opaque medium, (c) crystalline medium, (d) optically denser medium

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OMR SHEET, , SP 6, , Roll No., Sub Code., , Student Name, , Instructions, Use black or blue ball point pens and avoid Gel & Fountain pens for filling the OMR sheet., Darken the bubbles completely. Don’t put a tick mark or a cross mark, half-filled or over-filled bubbles will not be read, by the software., Correct, , ✔, , ✗, , Incorrect, , Incorrect, , Incorrect, , Do not write anything on the OMR Sheet., Multiple markings are invalid., , 1, , 21, , 41, , 2, , 22, , 42, , 3, , 23, , 43, , 4, , 24, , 44, , 5, , 25, , 45, , 6, , 26, , 46, , 7, , 27, , 47, , 8, , 28, , 48, , 9, , 29, , 49, , 10, , 30, , 50, , 11, , 31, , 51, , 12, , 32, , 52, , 13, , 33, , 53, , 14, , 34, , 54, , 15, , 35, , 55, , 16, , 36, , 56, , 17, , 37, , 57, , 18, , 38, , 58, , 19, , 39, , 59, , 20, , 40, , 60, , Check Your Performance, Total Questions:, Total Correct Questions:, , If Your Score is, , Score Percentage =, , Total Correct Questions, Total Questions, , × 100, , Less than 60%, > Average (Revise the concepts again), Greater than 60% but less than 75% > Good (Do more practice), Above 75%, > Excellent (Keep it on)

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169, , CBSE Sample Paper Science Class X (Term I), , Answers, 1. (a), 11. (a), , 2. (b), 12. (b), , 3. (b), 13. (a), , 4. (c), 14. (a), , 5. (c), 15. (c), , 21. (c), 31. (a), , 22. (a), 32. (b), , 23. (b), 33. (a), , 24. (d), 34. (b), , 25. (b), 35. (c), , 41. (c), 51. (b), , 42. (d), 52. (c), , 43. (c), 53. (c), , 44. (d), 54. (a), , 45. (b), 55. (b), , 6. (a), 16. (d), 26. (b), , 7. (c), 17. (c), 27. (d), , 8. (b), 18. (c), 28. (b), , 9. (c), 19. (b), 29. (a), , 10. (b), 20. (a), 30. (c), , 36. (b), 46. (a), , 37. (b), 47. (c), , 38. (b), 48. (a), , 39. (b), 49. (d), , 40. (a), 50. (b), , 56. (b), , 57. (b), , 58. (a), , 59. (c), , 60. (d), , EXPLANATIONS, Heat, , 1. 2KClO3( s) ¾¾¾® 2KCl( s) + 3O2( g ), Catalyst, , The reaction is endothermic in nature as KClO3, absorbs heat to form KCl and O2. The reaction, in which single reactant breaks down to form, two or more products is known as, decomposition reaction. It is a type of, decomposition reaction as KClO3 breaks down, to produce two products i.e. KCl and O2., , 6. In the given reaction,, 3Fe( s) + 4H2O( g ) ¾® Fe3O4 ( s) + 4H 2( g ), Fe is oxidised by gaining oxygen atoms and, hence, it acts as a reducing agent because the, substance which gets oxidised is called, reducing agent., 7. The reaction between copper oxide and, hydrogen take place as follows:, Reduction, , 2. The chemical formula of hydrated copper, sulphate is CuSO4 × 5H2O., , CuO( s) + H 2( g ) ¾® Cu( s) + H2O( l ), , On heating, water of crystallisation is removed, which leads to formation of CuSO4 that is, white in colour., , Oxidation, , This reaction is a redox reaction because, oxidation and reduction occurs simultaneously., , Heat, , CuSO4 × 5H2O ¾¾® CuSO4, (Blue), , (White), , The blue colour of hydrated copper sulphate is, due to presence of water of crystallistion which, changes into white due to removal of water of, crystallisation by heating., 3. Fe( s) + H2O( g ) ¾® Fe2O3 ( s) + H 2( g ), According to this reaction, when iron reacts, with steam of water, oxide of iron is formed, along with hydrogen gas., The iron oxide is basic in nature because iron is, metal and metallic oxide are basic in nature, and non-metal oxides are acidic in nature., , 2K( s) + 2H2O( l ) ¾® 2KOH( aq) + H 2( g ), A balanced chemical equation is one in which, the total number of atoms of each element are, equal on both sides of the equation., 5. NaCl is a salt which is neutral in nature and, the pH of neutral substances is equal to 7., Hence, C is the letter which denotes the area, where formation of neutral salt (NaCl) take, place., , H2CO3, Carbonic acid, (Parent acid), , + NH4 OH ¾¾® (NH4 )2 CO3, Ammonium, hydroxide, (Parent base), , Ammonium, carbonate, , Ammonium carbonate is formed by the, reaction between carbonic acid (parent acid), and ammonium hydroxide (parent base)., 9. The reaction between potassium iodide and, lead nitrate solution forms yellow insoluble, precipitate of lead iodide. By observing yellow, precipitate, one can identify the completion of, reaction., 10. Universal indicators are used to judge how, strong or weak a given acid or base. It is a, mixture of several indicators. It shows, different coloures at different concentrations of, hydrogen ions in a solution. It gives shade of, red in acidic range i.e. 1-6 and shade of blue in, basic range is 8-14., Hence, option (b) is correct which says that, universal indicator gives orange colour at, pH = 3 (acidic medium)., 11. Chloroplast are the site of photosynthesis as, they contain chlorophyll pigment. These are, the organelles present in the mesophyll cells of, green plants., , SAMPLE PAPER 6, , 4. Chemical equation shown in option (c) is, balanced one., , 8.

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170, , CBSE Sample Paper Science Class X (Term I), , 12. (i)-Right atrium, (ii)-Vena cava, (iii)-Pulmonary, arteries., These parts carry deoxygenated blood. Vena, cava carries deoxygenated blood from all body, parts to the right atrium., Pulmonary arteries carry deoxygenated blood, from right ventricle to the lungs., 13. Pepsin is a protein digesting enzymes present, in the stomach. It breaks down the larger, polypeptide into smaller peptide fragments., 14. Oesophagus is a tube that carries food from, your mouth to your stomach. It ensures the, swift movement of food by the way of rhythmic, relaxations and contractions of muscles., 15. The loss of water in the form of vapours from, the aerial parts of the plants is called, transpiration. Evaporation of water molecules, from leaf’s cells creates a suction (transpiration, pull) which pulls water from the xylem cells of, the roots., 16. The correct labelling is, A-Kidney, B-Ureter, C-Urinary bladder D-Urethra, Kidneys are the main excretory organ in, humans. It is involved in the formation of, urine. These wastes are removed from blood, by kidneys and are passed down to the urinary, bladder by a pair of ureters. The urethra, further releases the urine out of the body., 17. Due to refraction of light at interface of water, and air, light bends and the depth of a bucket, filled with water seems to be less than its, actual depth., 18. The image formation of an object on a screen, by a diverging mirror is shown below., A, , SAMPLE PAPER 6, , 23. Refractive index of diamond is more than that, of glass. As the light enters through the surface, of diamond, it suffers total internal reflection, and traps in it. That’s why diamond sparkles, more than glass., 24. The correct position of prism P1 and P2 to get, white light after recombination is shown below., White light, White light, White, light, White, light, , Screen, Screen, , Heated, 25. Na2CO3 ( s) ¾¾®, Na2O( s) + CO2( g ), , This reaction is endothermic as sodium, carbonate absorbs heat to from Na 2O and CO2., In this reaction, carbon dioxide gas is evolved., Hence, option (b) is correct., 26. As we know, lower the pH value, higher the, concentration of H + ions. The bar graph of, country C shows least value of pH. Hence, the, concentration of hydrogen ions is the highest, in country C., 27. Metal + Acid ¾® Salt + H 2, So, when metal reacts with dil. H2SO4 , it will, produce salt and hydrogen gas. The hydrogen, gas is lighter than air., 28. The white powder that is used by doctors to, treat fractured bone is called as plaster of Paris., On mixing with water, plaster of Paris changes, to gypsum to give hard solid mass., 1, 1, CaSO4 × H2O + 1 H2O ¾® CaSO4 × 2H2O, 2, 2, Gypsum, Plaster of Paris, , A¢, , object, B, , 22. As the image is formed by a plane mirror so, the magnification is +1. In figure, it is clear that, object is – 3 cm away from the mirror, so the, image will be + 3 cm away from the mirror., , image, B¢, , F, , The image formed by convex mirror is always, vitrual and diminished., 19. Both concave mirror and concave lens have, negative focal length., 20. Red light deviates least and violet light deviates, most. So, the angle of deviation of red ( r), yellow, ( y ) and violet ( v ) are in order of r < y < v., 21. As magnification is greater than 1. So, the, object is placed between pole and focus of, concave mirror to produce enlarged image., , This plaster of Paris is also used to ornate, designs on walls and ceiling., Hence, statement I, II and III are correct, whereas statement (IV) is incorrect as it does, not give off carbon dioxide (CO 2 ) on mixing, with water as shown in given reaction., 29. The metal A would be iron (Fe) as it does not, react with water (hot or cold), but reacts with, steam. Iron also reacts with dil HCl., Reaction with steam, 3Fe + 4H2O ¾®, Fe3O4, +, 4H2, (Iron), , (Steam), , (Ferrous oxide), , Reaction of Fe with dil. HCl, Fe + 2HCl ¾®, FeCl2, , (Iron), , (dil.), , (Ferrous chloride), , (Hydrogen), , +, , H2 ­, , (Hydrogen)

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171, , CBSE Sample Paper Science Class X (Term I), , 30. When barium chloride combines with sodium, sulphate in aqueous solution, then white, precipitate of barium sulphate is formed which, is insoluble in water. So, III test tube shows, correct observation., Na 2SO4 + BaCl2 ¾¾® BaSO4 ¯ +2 NaCl, (white ppt), , 31. A and R are both true and R is the correct, explanation of A., The phenomenon due to which metals are, slowly eaten by the reaction of air, water and, chemicals present in the atmosphere is called, corrosion. Corrosion of iron is known as, rusting of iron. It damages the articles of iron,, therefore to prevent rusting of iron, paints are, applied on iron materials., 32. A and R are true, but R is not correct explanation, of A., Bleaching powder is basic in nature because it, reacts with acid and forms salt and water., 33. Both A and R are true and R is the correct, explanation of A., During the breathing cycle, when air is taken, in and let out, the lungs always contain a, residual volume of air so that there is suficient, time for oxygen to be absorbed and for the, carbon dioxide to be released., 34. Both A and R are correct, but R is not the, correct explanation of A., When the Sun is slightly below the horizon, its, light coming from less dense to more dense air,, is refracted downwards. Because of this, the, Sun appears to be raised above the horizon, and so, the rising Sun can be seen about 2, minutes before actual sunrise. Similarly, due to, atmospheric refraction the Sun can be seen for, about 2 min even after the actual sunset., The time difference between actual sunrise and, apparent sunrise is about 2 minutes., , 36. Anaerobic respiration takes place in absence of, oxygen. During anaerobic respiration in yeast, cells, pyruvate breakdown to produce ethanol, (alcohol), carbon dioxide and energy., , 37. Diffusion of oxygen from the alveoli into the, blood does not require energy from respiration, because diffusion is a passive process and do, not need energy to occur., 38. In the alveoli, exchange of gases takes place,, i.e. oxygen from alveolar air diffuses into blood, and carbon dioxide from blood into alveolar, air., Other statements are incorrect and can be, corrected as, (a) During inhalation, ribs lift up and, diaphgram flattens to increase the size of, chest cavity., (c) Haemoglobin present in RBCs has a very, high affinity for oxygen., (d) Alveoli increases the surface area for, exchange of gases., 39. Given, m = 3, r = 30°, i = ?, Using Snell’s law,, sin i, sin r, sin i, 3=, sin 30°, m=, , \, Þ, or, , sin i =, , 3, 2, , æ 3ö, i = sin -1 ç ÷ = 60°, è 2 ø, , 40. Given, u = - 20 cm, f = - 25 cm, Using mirror formula,, 1 1 1, = +, f u v, 1 1 1, 1, 1, Þ, = - =, v, f u ( -25 ) ( -20 ), -4 + 5, 1, =, =, 100, 100, Þ, v = 100 cm, = 1 ´ 10 2 cm, Here, v is positive. So, image is formed behind, the mirror., 41. Some organisms derive nutrition from plants, or animals without killing them. This parasitic, nutritive strategy is used by a variety of, organisms like Cuscuta (amar-bel), ticks, lice,, leeches and tapeworms., 42. Lymph is a colourless fluid that contains, white blood cells. It drains into the streams via, lymphatic system., , SAMPLE PAPER 6, , 35. The colour change shown by methyl orange, and phenolphthalein are correctly shown in, the table. Whereas correct colour change of, blue litmus and turmeric is as follows, (i) Blue litmus turns red in acidic medium, and show no change in basic medium., (ii) Turmeric remains same (yellow) in, acidic medium, but becomes red in basic, medium., , In absence of O 2, (in yeast), , Pyruvate ¾¾¾¾¾® Ethanol + CO2 + Energy

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172, , CBSE Sample Paper Science Class X (Term I), , Lymph carries digested and absorbed fat, from intestine and drains excess fluid from, extracellular space back into the blood., 43. Given,, , Þ, , Power, P = - 10 D, 100, P=, f (in cm), 100, - 10 =, f, , or, f = - 10 cm, Concave lens has negative focal length., 44. Given, m = - 2, v = 40 cm, v, v 40, Magnification, m =, Þ u= =, u, m -2, or, , u = -20 cm, , 45. The object is placed at finite distance, so the, image will formed between focus and optical, centre and on the same side of lens as object., The image is small in size, virtual and erect., The focal length of concave lens is always, negative., 46. The slope of sin i versus sin r graph, represents refractive index of medium, sin i, i.e.,, m=, sin r, so, the slope of colour C is more, hence its, refractive index is highest among rest of the, colours., 47. Given, f = 20 cm, ho = 5 mm = 0.5 cm, u = - 10 cm, By lens formula,, 1 1 1, - =, v u f, , SAMPLE PAPER 6, , 1, 1, 1, =, v ( -10 ) 20, 1, 1, 1, =, Þ v = - 20 cm, v 20 10, Magnification, m =, , v - 20, =, =2, u - 10, , 48. To be approved by inspection authority,, cables should be malleable (can be beaten, into thin sheets), ductile (can be drawn into, thin wires), good conductor of electricity and, have high melting point., All these properties are present in cable D, only. Therefore, the product A, B and C were, disapproved as cable material as they do not, have all these properties., , 49. Hydrogen gas is evolved, when zinc reacts with, dil.sulphuric acid., Zn( s) + dil.H2SO4 ¾® ZnSO4( aq) + H 2( g ), 50. Zinc sulphate is produced during the reaction, between Zn and dil. H2SO4 ., Zn( s) +, Zinc, , H2SO4 ( aq), Dil. sulphuric acid, , ¾® ZnSO4 ( aq) +, Zincsulphate, , H2, Hydrogen, , 51. The correct chemical equation involved in the, experiment is, Zn( s) + H2SO4 ( aq) ¾® ZnSO4( aq) + H 2( g ), 52. Soap solution provides the medium for H 2 gas to, get trapped in small parts and determined its, presence by taking a burning candle near the, soap bubbles filled with hydrogen gas., 53. Haemodialysis or artificial kidney is a device to, remove nitrogenous waste products (urea) from, the blood. This procedure is used to treat both, temporary and permanent kidney failure., 54. Normally in a healthy adult, the initial filtrate in, the kidneys is about 180 L daily. However, the, volume actually excreted is only one or two litre, a day, because the remaining filtrate is, reabsorbed in the kidney tubules., 55. Urea from blood has diffused into dialysis fluid, in the dialysis., Hence, the blood returning to the body ( X ) has a, low concentration of urea and liquid (Y ) has the, highest concentration of salts and urea., 56. Statement II and III are incorrect and can be, corrected as, II. The waste products from the blood pass into, dialysing fluid by diffusion., III. This process is similar to the function of the, kidney, but it is different since there is no, reabsorption involved., 57. Due to atmospheric refraction, wavering and, flickering of objects is seen through a turbulent, steam of hot air., 58. The phenomena caused due to atmospheric, refraction are twinkling of stars at night, advance, sunrise and delayed sunset., 59. When light comes from stars to the observer, it, suffers from atmospheric refraction due to, different layers of earth’s atmosphere. The, position of stars also seems to be changing, continuously., 60. Molecules are closely packed in low temperature,, so the colder layers of air present in atmosphere, are considered as optically denser medium.

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SAMPLE PAPER 7, SCIENCE, A Highly Simulated Practice Questions Paper, for CBSE Class X (Term I) Examination, , Instructions, (i) This paper is divided into three Sections:, (a) Section A – Contains 24 questions. Attempt any 20 questions., (b) Section B – Contains 24 questions. Attempt any 20 questions., (c) Section C – Contains 12 questions. Attempt any 10 questions., (ii) Each questions carries 0.80 mark., (iii) There is NO negative marking., Maximum Marks : 40, Time allowed : 90 Min., , Roll No., , Section A, Section-A consists of 24 questions. Attempt any 20 questions from this section. The first attempted, 20 questions would be evaluated., , 1. Choose the correct observation when aluminium strip is kept in freshly prepared, ferrous sulphate solution in a test tube., (a) Light green colour solution changes to colourless solution, (b) A colourless gas smells like burning sulphur is observed, (c) Green colour of solution slowly turns brown, (d) The test tube becomes slightly hot, , 2. A student adds few drops of the universal indicator to a solution of dilute hydrochloric, acid in the way shown here., , Drops of universal, indicator, , Hydochloric, acid, , Identify the colour change of dil. HCl solution., (a) Green, , (b) Red, , (c) Blue, , (d) Colourless

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174, , CBSE Sample Paper Science Class X (Term I), , 3., Metal, Cold water, , Gas, , Metal hydroxide, , Which of the following two combinations are correct ?, Metal, Gas evolved, (i) Cu, No, (ii) Na, No, (iii) Ca, Yes, (iv) Fe, Yes, Codes, (a) (i) and (ii), (b) (ii) and (iii), (c) (i) and (iii), (d) (iii) and (iv), , 4. Which of the following correctly represents a balanced chemical equation?, (a) C2 H6 + 4O2 ¾®2 CO2 + 2 H2 O, , (b) 2 C2 H6 + 5O2 ¾® 4CO2 + 5H2 O, , (c) 2 C2 H6 + 7O2 ¾® 4CO2 + 6H2 O, , (d) C2 H6 + 6O2 ¾® CO 2 + 6H2 O, , 5. A few drops of lemon juice is added to milk to make curd. After a few hours, the milk, turns into curd. The given graph is plot by observing the given situation., , pH, value, O, , Time, , What does the graph indicates?, (a) The acidity of milk increases with time, (b) The pH value of milk becomes high with time, (c) The basicity of milk increases with time, (d) All of the above, , 6. In the reaction of manganese dioxide with hydrochloric acid,, , SAMPLE PAPER 7, , MnO 2 ( s) + 4 HCl( aq) ¾® MnCl 2 ( aq) + 2H 2 O( l) + Cl 2 ( g), Which option in the given table correctly represents the substance reduced and the oxidising, agent?, Option, , Substance reduced, , Oxidising agent, , (a), , MnO 2, , MnO 2, , (b), , HCl, , MnCl 2, , (c), , MnCl 2, , Cl 2, , (d), , H 2O, , H 2O

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175, , CBSE Sample Paper Science Class X (Term I), , 7. The chemical reaction between potassium iodide and lead nitrate can be classified as, (a) decomposition reaction, (b) double displacement reaction, (c) displacement reaction, (d) redox reaction., , 8. Which of the given option correctly represents the parent acid and parent base of, magnesium nitrate?, Parent acid, (a) MgCl 2, (b) H 2 CO 3, (c) HNO 3, (d) HNO 3, , Parent base, NaOH, Mg 3 N 2, MgCl 2, Mg(OH) 2, , 9. When electricity is passed through an aqueous solution of NaCl, then, (a) chlorine gas is given off at the anode, (b) sodium hydroxide solution is formed near the cathode, (c) hydrogen gases is given off at the cathode, (d) All of the above, , 10. Which of the following statement is true about the action of sodium carbonate on, litmus paper?, (a) The red litmus turns blue, (b) The blue litmus turns red, (c) No change on litmus, (d) First blue colour appears, then it becomes colourless, , 11. Carefully study the diagram of the human circulatory system with labels (i), (ii), (iii) and, (iv). Select the option which gives correct identification and main function and/or, characteristic., (i), , Right side of heart, , (iii), , Left side of heart, , (iv), (ii), , SAMPLE PAPER 7, , (a) (i) Pulmonary Artery – Thick walled and carry blood from body to lungs., (b) (ii) Capillary – One cells thick and helps in exchange of gases., (c) (iii) Pulmonary veins – Thick walled and carry blood from lungs to various body parts., (d) (iv) Aorta – Thin walled and carry deoxygenated blood to the lung capillaries.

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176, , CBSE Sample Paper Science Class X (Term I), , 12. Identify the option that indicates correct material digested in the location (i), (ii) and (iii)., (i ), , (ii), , (iii), , (a) (i)-Starch, (ii)-Fats, (iii)-Proteins, (b) (i)-Proteins, (ii)-Carbohydrates, (iii)-Starch, (c) (i)-Starch, (ii)-Proteins, (iii)-Proteins, (d) (i)-Fats, (ii)-Proteins, (iii)-Fats, , 13. What is the correct sequence of air during exhalation?, (a) Alveoli ® Bronchus ® Bronchioles ® Trachea ® Nostrils, (b) Nostrils ® Pharynx ® Larynx ® Trachea ® Alveoli, (c) Alveoli ® Trachea ® Pharynx ® Larynx ® Nostrils, (d) Alveoli ® Trachea ® Larynx ® Pharynx ® Nostrils, , 14. The figure given below shows a structure of nephron with labels (i) to (iv). Identify the, correct label with its functions., (ii), , (iii), , (i), , SAMPLE PAPER 7, , (iv), , (a) (i) Renal artery – Takes impure blood to the kidneys, (b) (ii) Bowman’s capsule – Collects the blood from tubules, (c) (iv) Collecting duct – Dilution of urine, (d) (iii) Tubular part of nephron – Reabsorbs salts and major amount of water of nephron

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177, , CBSE Sample Paper Science Class X (Term I), , 15. Identify the correct statement about the process of haemodialysis represented by the, diagram given below. Arrow indicates the flow of dialysing solution., Line from, artery to pump, , Line from, apparatus, to vein, , Tubing made up of, a selectively, permeable membrane, , Dialysing, solution, , Fresh dialysing Used dialysing, solution solution (with urea and, excess salts), , (a) During this passage, the waste products from blood pass into dialysing fluid by faciliated, diffusion., (b) During the process, reabsorption of salts and minerals occurs., (c) The patient’s blood pass through the tubes having impermeable lining., (d) The fresh dialysing solution is entering the patient’s body and impure dialysing solution is, coming out of the body simultaneously., , 16. Observe the flow chart of breakdown of glucose by various pathways., Glucose, (6-carbon, molecule), , B, , Ethanol + Carbon dioxide + Energy, , A, Pyruvate, (3-carbon, molecule, +, Energy), , C, , Lactic acid + Energy, , D, , Carbon dioxide + Water + Energy, , Match the labelling referred in Column I and correlate with the Column II., Column I, , Column II, 1. This process takes place in the mitochondria., , B, , 2. It occurs when there is lack of oxygen in muscles., , C, , 3. This process takes place in yeast during fermentation., , D, , 4. It is first step in the break down of glucose into pyruvate., , Codes, A B, (a) 4 3, (c) 4 2, , C, 2, 1, , D, 1, 3, , A B, (b) 4 1, (d) 4 3, , C, 3, 1, , D, 2, 2, , 17. When light falls on a smooth polished surface, then most of the light is, (a) reflected in same direction, (c) refracted into the second medium, , (b) refracted in different directions, (d) scattered away, , SAMPLE PAPER 7, , A

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178, , CBSE Sample Paper Science Class X (Term I), , 18. Four students A, B , C and D carried out measurement of focal length of a concave, mirror as shown in the four diagrams., , A, , B, , C, , D, , The best result will be obtained by which student ?, (a) Student A, (b) Student B, (c) Student C, (d) Student D, , 19. In a glass prism, the emergent ray is not parallel to the incident ray because, (a) the laws of reflection do not hold in case of glass prism., (b) the refracting surfaces are inclined at an angle., (c) the angle of refraction in glass is greater than the angle of incidence., (d) the angle of refraction in glass is greater than the angle of emergence., , 20. Consider these two indices of refraction; flint glass: 1.52 and diamond: 2.42. Based on, the refractive indices of these materials, choose the correct option., (a) The speed of light in diamond > the speed of light in flint glass., (b) The speed of light in flint glass is equal to the speed of light in diamond., (c) The speed of light in flint glass > the speed of light in diamond., (d) The speed of light is independent of the refractive index of material., , 21., , M1, , i, , SAMPLE PAPER 7, , M2, , Examine the above diagram and choose which of the following is correct?, (a) The angle of incidence should be 30° for parallel rays., (b) The angle of reflection is greater than angle of incidence in this case, (c) If the angle between M1 and M2 is less than 90°, then the rays will become parallel, (d) If M1 and M2 are inclined at 90°, then the incident and reflected rays will be parallel., , 22., A, , M, C, , F, , P

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179, , CBSE Sample Paper Science Class X (Term I), , A ray of light AM is incident on a concave mirror as shown. Then which of the following ray, diagrams is correct for the reflected ray?, A, , M, , A, , (a), , M, , (b), C, , F, , A, , P, , C, , M, , A, , (c), C, , F, , F, , M, , (d), , P, , C, , 23., , P, , F, , P, , mw, mg, , In the given figure, path of a parallel beam of light passing through a convex lens of, refractive index m g kept in a medium of refractive index m w , which of the following is, correct?, 1, (a) m g > m w, (b) m g = m w, (c) m g < m w, (d) m g =, mw, , 24. The minute particles and molecules of the atmosphere deflect the sunlight in all, directions. Which of the following phenomenon is involved here?, (a) Dispersion, (b) Scattering, (c) Refraction, (d) Tyndall effect, , Section B, Section B consists of 24 questions (Sl. No. 25 to 48). Attempt any 20 questions from this section. The first, attempted 20 questions would be evaluated., , 25. Sodium hydrogen carbonate ¾¾®, Na 2 CO 3 + X + H 2 O, D, Identify the correct option from the given table which represents the type of reactions, and gas evolved., Gas evolved, , (a), , ü, , 7, , (b), , 7, , ü, , (c), , ü, , ü, , (d), , 7, , 7, , 26. A boy recorded a pH value of soil sample (A), rain water sample (B), tap water sample, (C) and vinegar (D). He plotted the pH value of the four samples in the given graph., 7, pH, value, , A, , B, , C, , D, , SAMPLE PAPER 7, , Exothermic

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180, , CBSE Sample Paper Science Class X (Term I), , Which of the following sample has highest concentration of hydrogen ion?, (a) Soil sample, (b) Tap water sample, (c) Rain water sample, (d) Vinegar, , 27. The diagram shows the reaction between dil. H 2 SO 4 and five different metals,, magnesium, zinc, aluminium, iron and copper., , 15 mL of dilute sulphuric acid is added to each of them. Identify the incorrect statement., (a) The rate of evolution of hydrogen gas bubbles is not same in each test tube, (b) The rate of formation of bubbles is the fastest in the case of magnesium, (c) No bubbles are seen in case of copper, (d) The reactivity order of these metals in Mg > Zn > Fe > Al > Cu, , 28. The electronic configuration of six elements A to F are given in the table below., Electronic configuration, , Formula of compounds, , (i), , A : 2, 1, , B : 2, 6, , A 2B, , (ii), , B : 2, 6, , C : 2, 5, , B 2C 3, , (iii), , C : 2, 5, , D : 2, 2, , C 2D 3, , (iv), , E : 2, 8, 5, , F : 2, 8, 8, 2, , EF 3, , Which of the following compound has wrong formula?, (a) (i) and (ii), (b) (ii) and (ii), (c) (iii) and (iv), (d) (ii) and (iv), , 29. A student took a blue litmus paper and dipped it in dil. H 2 SO 4 and then in dil. NaOH, , SAMPLE PAPER 7, , solution. He observed that, (i) the colour of litmus paper changes to red., (ii) the colour of litmus paper first changes to red and then to blue., (iii) the colour of litmus paper changes from blue to colourless., (iv) the colour of litmus paper shows different colours in different mediums., Which of the following observations is true?, (a) (i) and (ii), (b) (ii) and (iv), (c) (iii) and (iv), (d) (i) and (iii), , 30. In four test tubes, there are different sample. On addition of phenolphthalein, the test, tube II and III shows pink colour and I and IV shows no change. Moreover, red, cabbage water is added to each sample. The test tube IV shows purple colour, I shows, red and II and III shows blue colour., I, , II, , III, , IV

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181, , CBSE Sample Paper Science Class X (Term I), , Which of the following test tubes contain sample with pH < 7?, (a) I and IV, (b) II and III, (c) Only I, (d) Only II, Direction (Q. No. 31 to 34) Consist of two statements – Assertion (A) and Reason (R). Answer these, questions selecting the appropriate option given below :, (a) Both A and R are true and R is the correct explanation of A., (b) Both A and R are true, but R is not the correct explanation of A., (c) A is true, but R is false., (d) A is false, but R is true., , 31. Assertion MnO 2 + 4HCl ¾® MnCl 2 + Cl 2 + 2H 2 O is a redox reaction., Reason In a redox reaction, oxidation and reduction take place simultaneously., , 32. Assertion Aluminium chloride is a basic salt., Reason Aluminium chloride is a salt of strong acid and a weak base., , 33. Assertion In a healthy adult, the initial filtrate in the kidneys is about 180 L daily, but, the actual volume excreted is only a litre a day., Reason Most of the filtrate is lost from the body in the form of sweat., , 34. Assertion It is impossible to see a virtual image with naked eyes., Reason The rays do not actually emanate from a virtual image., , 35. The table given below shows the reaction of a few elements with acids and base to, evolve hydrogen gas., Elements, , Acid, , Base, , M, , ü, , ü, , N, , 7, , 7, , O, , ü, , 7, , P, , ü, , ü, , Which of the following elements can form amphoteric oxides?, (a) M and N, (b) N and O, (c) M and P, (d) N, M and P, , 36. In which of the following vertebrate group /groups, heart does not pump oxygenated, (b) Amphibians and reptiles, (d) Pisces only, , 37. During photosynthesis, which of the following event takes place?, (a) Oxidation of CO 2 into carbohydrates, (b) Reduction of carbohydrates into CO 2, (c) Reduction of CO 2 into carbohydrates, (d) Oxidation of carbohydrates into CO 2, , SAMPLE PAPER 7, , blood to different parts of the body?, (a) Pisces and amphibians, (c) Amphibians only

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182, , CBSE Sample Paper Science Class X (Term I), , 38. The excretory system of human being consists of, (a) a kidney, a ureter, a urinary bladder and a urethra., (b) a pair of kidneys, a ureter, a pair of urinary bladders and a urethra, (c) a pair of kidneys, a pair of ureters, a urinary bladder and a urethra, (d) a kidney, a pair of ureters, a urinary bladder and a urethra, , 39. One-half of a convex lens is covered with a black paper. The size of image produced, will be, (a) half the size of object, (b) same as that of object, (c) two-third the size of object, (d) one-fourth the size of object, , 40. Two lenses of focal length 20 cm and -10 cm are combined as shown. The combination, of these will become, , (a) converging lens with focal length 20 cm, (c) converging lens with focal length -20 cm, , (b) diverging lens with focal length -10 cm, (d) diverging lens with focal length 10 cm, , 41. Enzyme trypsin and pepsin works in, (a) basic and acidic medium, respectively, (b) acidic and basic medium, respectively, (c) acidic medium only, (d) neutral medium only, , 42. The force that blood exerts against the wall of vessels is, (a) more in veins and less in arteries, (c) more in capillaries, , (b) more in arteries and less in veins, (d) more in both veins and arteries, , 43. An object of size 7 cm is placed at 27 cm in front of a concave mirror of focal length, 18 cm. At what distance from the mirror should be placed, so that a sharp focused, image can be obtained?, (a) 27 cm, (b) 54 cm, (c) -27 cm, (d) -54 cm, , SAMPLE PAPER 7, , 44., , Incident light, , 45°, , 30°, , Air, Medium, P, , Air, , Incident light, , 45°, , 20°, , Air, Medium, Q, , Air, , For the same angle of incidence of 45°, the refraction angle in two transparent media P and Q, is 30° and 20° , respectively. Which one of the following is correct?, (a) Medium P is the denser medium than medium Q, (b) Speed of light in both media is same., (c) Medium Q is the denser medium than medium P, (d) Angle of emergence for both media are greater than incidence angle.

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183, , CBSE Sample Paper Science Class X (Term I), , 45., , O, F, 20 cm, , The focal length of above mirror is 10 cm, the image will formed, (a) at 20 cm behind the mirror, (b) at focus of mirror, (c) between mirror and focus, (d) at the centre of curvature of mirror, , 46. A convex lens has focal length 30 cm. If an object is placed at a distance of 15 cm from, it, then the magnification produced by the lens is, (a) 6, (b) 2, (c) 1, , (d) 0.5, , 47. A beam of light when passes through a glass prism, a spectrum is observed. But when, same beam is passed through a hollow glass prism, then, (a) same spectrum is obtained, (b) spectrum becomes brighter, (c) spectrum gets reversed, (d) no spectrum is observed, , 48., , Element, , Ductile, , Melting point, , Electrical conductivity, , A, , Yes, , High, , Yes, , B, , Yes, , High, , No, , C, , No, , Low, , No, , D, , Yes, , Low, , Yes, , Which of the above elements can be used for making wires?, (a) A, B, (b) B, C, (c) A, D, , (d) Only A, , Section C, This Section-C consists of three Cases followed by questions. There are a total of 12 questions in this, section. Attempt any 10 questions from this section. The first attempted 10 questions would be evaluated., Case I. The samples of sodium chloride, potassium iodide, barium chloride or any other salt are, taken from the science laboratory. A small amount of a sample is taken on a metal spatula and, heated directly on the flame as shown in figure given below :, , Burner, , Heating a salt sample on a spatula, , SAMPLE PAPER 7, , Spatula, containing, sample

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184, , CBSE Sample Paper Science Class X (Term I), , A circuit as shown in Fig. is used to test the electrical conductivity of the given salt solution., Battery, –, +, , Bulb, Switch, , Beaker, Graphite rod, Salt solution, under test, , 49. The physical state and properties of the salt samples used in the given activity is, (a) all are crystalline solids, (b) all are brittle, (c) all are having high melting point, (d) All of the above, , 50. Choose the correct observation when the salt sample is taken on a metal spatula and, heated directly on the flame, (a) the salt undergo sublimation, (b) the salts melt immediately, (c) the salts given out characteristics flame upon heating, (d) the salts do not melt easily, , 51. Which of the following compounds will not conduct electricity in aqueous solution?, (a) NaCl, (c) CaCl 2, , (b) CCl 4, (d) KCl, , 52. A student noted the following observations with four compounds P, Q, R and S., Melting point (K), , Boiling point (K), , P, , 1074, , 1686, , Q, , 250, , 350, , R, , 290, , 391, , S, , 2850, , 3120, , SAMPLE PAPER 7, , Compound, , Which of the following compounds are ionic in nature?, (a) P and Q, (b) Q and R, (c) R and S, (d) P and S

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185, , CBSE Sample Paper Science Class X (Term I), , Case II. Amoeba is a single celled organism. It ingest food with the help of ‘X’. These form the food, vacuole over the food particle. In food vacuole, the complex food is broken down into smaller, molecules which then diffuse into the cytoplasm. The remaining undigested food is expelled out by, the process ‘Y ’., B, (i), , X, C, , (ii), , A, , (iii), , (iv), Y, , 53. In diagram labelled A, B and C indicates, (a) food particle, food vacuole and nucleus, (c) food vacuole, nucleus and food particle, , (b) food particle, nucleus and food vacuole, (d) food particle, nucleus and pseudopodia, , 54. The labelled part Y represents which stage of nutrition?, (a) Ingestion, , (b) Digestion, , (c) Egestion, , (d) Absorption, , 55. The characteristics of labelled part X is, (a) it is small hair-like structures present on Amoeba body, (b) it is finger-like projections on cell surface, (c) it is tube-like structures coming out of the body, (d) it is suckers which is attached to the wall of the intestine, , 56. Which of the following is true for the process of nutrition in Amoeba?, (i) The food is taken in by the entire surface, (ii) The pseudopodias are the permanent structures on cell surface of amoeba, (iii) The cell membrane ruptures and eliminates out undigested food., (iv) Within the vacuole, egestion of food occurs., (a) (i) and (iii), (b) (i) only, (c) (i) and (ii), (d) (ii) and (iv), Case III. A student suggested the following guidelines to his friend for doing the experiment on, tracing the path of a ray of light on passing through a rectangular glass slab, for three different, angles of incidence, i, Q, r, r, S, , e, , R, , A. Draw the outline of the glass slab at three positions on the drawing sheet., B. Draw normals on the top side of these outlines near their right end., C. Draw the incident rays on the three outlines in directions making angles of 30°, 45° and, 60° with normals drawn., , SAMPLE PAPER 7, , P

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186, , CBSE Sample Paper Science Class X (Term I), , D. Fix two pins vertically on each of these incident rays at two points exactly 1 cm apart., E. Look for the images of the feet of these pins while fixing two pins, from the other side,, to get the refracted ray., , 57. When he showed these guidelines to his teacher, the teacher told him that two of them, need to be corrected and modified. These two guidelines are, (a) B and C, (b) C and D, (c) D and E, (d) B and D, , 58. How may refractions of light ray occur on passing through a glass slab?, (a) One, (c) Three, , (b) Two, (d) Four, , 59. He performs the experiment for two different values of angle of incidence : Ði = 30° and, Ði = 45°. The set of values of the angle of refraction ( Ðr) and angle of emergence ( Ðe), he, is likely to observe in the two cases, are, (a) [Ðr = 30° , Ðe = 20°] and [ Ðr = 45° , Ðe = 28°], (b) [Ðr = 20°, Ðe = 30°] and [Ðr = 45°, Ðe = 28° ], (c) [Ðr = 20°, Ðe = 30°] and [Ðr = 28°, Ðe = 45°], (d) [Ðr = 30°, Ðe = 20°] and [Ðr = 28°, Ðe = 45°], , 60. He noted some observations from this demonstration, choose the correct one., , SAMPLE PAPER 7, , (a) Ði is more than Ðr but (nearly) equal to Ðe, (b) Ði is less than Ðr but (nearly) equal to Ðe, (c) Ði is more than Ðe but (nearly) equal to Ðr, (d) Ði is less than Ðe but (nearly) equal to Ðr

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OMR SHEET, , SP 7, , Roll No., Sub Code., , Student Name, , Instructions, Use black or blue ball point pens and avoid Gel & Fountain pens for filling the OMR sheet., Darken the bubbles completely. Don’t put a tick mark or a cross mark, half-filled or over-filled bubbles will not be read, by the software., Correct, , ✔, , ✗, , Incorrect, , Incorrect, , Incorrect, , Do not write anything on the OMR Sheet., Multiple markings are invalid., , 1, , 21, , 41, , 2, , 22, , 42, , 3, , 23, , 43, , 4, , 24, , 44, , 5, , 25, , 45, , 6, , 26, , 46, , 7, , 27, , 47, , 8, , 28, , 48, , 9, , 29, , 49, , 10, , 30, , 50, , 11, , 31, , 51, , 12, , 32, , 52, , 13, , 33, , 53, , 14, , 34, , 54, , 15, , 35, , 55, , 16, , 36, , 56, , 17, , 37, , 57, , 18, , 38, , 58, , 19, , 39, , 59, , 20, , 40, , 60, , Check Your Performance, Total Questions:, Total Correct Questions:, , If Your Score is, , Score Percentage =, , Total Correct Questions, Total Questions, , × 100, , Less than 60%, > Average (Revise the concepts again), Greater than 60% but less than 75% > Good (Do more practice), Above 75%, > Excellent (Keep it on)

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188, , CBSE Sample Paper Science Class X (Term I), , Answers, 1. (c), 11. (b), , 2. (b), 12. (c), , 3. (c), 13. (d), , 4. (c), 14. (d), , 21. (d), 31. (a), , 22. (c), 32. (d), , 23. (b), 33. (c), , 24. (b), 34. (d), , 41. (a), 51. (b), , 42. (b), 52. (d), , 43. (d), 53. (b), , 44. (c), 54. (c), , 5. (a), 15. (a), 25. (b), , 6. (a), 16. (a), 26. (d), , 7. (b), 17. (a), 27. (d), , 8. (d), 18. (a), 28. (d), , 9. (d), 19. (b), 29. (b), , 10. (a), 20. (c), 30. (c), , 35. (c), 45. (d), 55. (b), , 36. (d), 46. (b), 56. (a), , 37. (c), 47. (d), 57. (d), , 38. (c), 48. (d), 58. (b), , 39. (b), 49. (d), 59. (c), , 40. (a), 50. (d), 60. (a), , EXPLANATIONS, 1. The freshly prepared ferrous sulphate solution, was green in colour before placing aluminium, strip in it. Then the colour of solution changes, to brown slowly because the displacement, reaction takes place as Al is more reactive than, Fe, according to reactivity series., FeSO4( aq) + Al( s ) ¾® Al 2( SO4 )3( aq) + Fe, ( Brown ), , (Green), , 2. The student would observed that the colour of, acid changes to red after the addition of, universal indicator. This shows that, hydrochloric acid is a strong acid with an, approximate pH of 2., , 6. MnO 2 is getting reduced to MnCl 2 by removal, of oxygen atoms. So, MnO 2 acts as an, oxidising agent also because the substance, which is getting reduced is called oxidising, agent., 7. The reactions in which two compounds, exchange their ions to form two new compounds, are called double displacement reactions., Hence, the given chemical reaction is a type of, double displacement reaction., 2KI( aq ), , + Pb(NO)3( aq) ¾®, , Potassium iodide, , Lead, nitrate, , 3. (i) Copper does not react with cold water and, hence, no gas evolved., (ii) Sodium reacts violently with cold water., 2Na + 2H2O ¾® 2NaOH + H2 + Heat, Therefore, hydrogen gas is evolved., (iii) Calcium reacts with cold water and forms, Ca(OH) 2 and hydrogen gas., Ca( s ) + 2H2O( l ) ¾® Ca(OH)2( aq) + H2( g ), Calcium, , Cold, water, , Calcium, hydroxide, , Hydrogen, , (iv) Fe does not react with water at all. Thus,, no gas is evolved., , SAMPLE PAPER 7, , equation as in this reaction, total no. of, elements in all the elements are balanced or, equal in both sides of the equation., 5. The milk is almost neutral and its pH range is, around 6-7., On addition of lemon juice, which is acidic in, nature, increase the acidity of milk and with, time, milk turns into curd. This decreases, the pH of milk which is then converted into, curd., , Lead iodide, , Potassium, nitrate, , 8. Magnesium nitrate is formed by the reaction, between nitric acid (parent acid) and, magnesium hydroxide (parent base)., Mg(OH)2( s) + 2HNO3( aq) ¾® Mg(NO3 )2( aq), + 2H2O( l ), 9. All of the given statements are correct., 2NaCl(aq) + 2H2O(l), Sodium, chloride, , Electric, current, , 2NaOH(aq), Sodium, hydroxide, , Water, , + Cl2(g) + H2(g), , Hence, option (c) is correct., 4. 2C 2H 6+ 7O 2 ¾® 4CO 2+ 6 H 2O is a balanced, , 2KNO3( aq) + PbI2( s), , Chlorine, , Hydrogen, , When electricity is passed through an aqueous, solution of sodium chloride, it decomposes to, form sodium hydroxide near the cathode,, chlorine gas is given off at the anode and, hydrogen gas at the cathode., This process is called chlor-alkali process., 2NaCl(aq) + 2H2O(l), Sodium, chloride, , Water, , Electric, current, , 2NaOH(aq), (Sodium hydroxide), , + Cl2(g) + H2(g), Chlorine, , Hydrogen

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189, , CBSE Sample Paper Science Class X (Term I), , 10. The red litmus turns blue on the action of, sodium carbonate because sodium carbonate, is derived from a weak acid and a strong base., Thus, sodium carbonate is basic in nature., 11. (ii) Capillaries are the smallest vessels and, have one-cell thick walls. Exchange of, material between the blood and, surrounding cells takes place across this, thin wall., The incorrect options can be corrected as, (i) Pulmonary artery–Thick-walled and, carries blood from heart to lungs., (iii) Pulmonary veins–Thin-walled and carry, blood from lungs to heart., (iv) Aorta–Thick-walled and carries, oxygenated blood from left ventricle to, other body parts., 12. (i) Mouth is the first part of the digestive, system from where the food enters into the, alimentary canal. In mouth, digestion of, starch occur with the help of salivary, amylase enzyme., (ii) In stomach, protein is digested by the, enzyme pepsin., (iii) In small intestine, digestion of, carbohydrates, protein and fats occur., 13. In order for the lungs to expel air, the, diaphragm relaxes which pushes up the lungs., Then the air flows from alveoli to the trachea, then through the larynx and pharynx to the, nasal cavity where it is expelled out of the, body via nostrils., 14. The labelled part are as follows, (i) Renal artery, (ii) Bowman’s capsule, (iii) Tubular part of nephron, (iv) Collecting duct, , 15. Artificial kidney is a device used to remove, nitrogenous waste products from the blood, through dialysis. It contains number of tubes, with a semipermeable lining suspended in a, , 16. In all cases, the first step is breakdown of, glucose (6-C molecule) into pyruvate (3-C, molecule). This process occur in the cytoplasm, (A). Further, the pyruvate may be converted, into ethanol and carbon dioxide. This process, takes place in yeast (B) during fermentation., Breakdown of pyruvate using oxygen takes, place in the mitochondria (D). This process, breaks up pyruvate into carbon dioxide and, water. In the lack of oxygen in the muscle cells, (C), the pyruvate is converted into lactic acid., 17. When light falls on a smooth polished surface,, most of it is reflected in the same direction, this, is known as regular reflection., 18. Student A will obtain the best result for correct, measurement of focal length, sharp image, must be obtained on the screen and the, meterscale must be correctly placed between, screen and centre of concave mirror., 19. As the two reflecting surfaces of prism are not, parallel to each other., So, these surfaces are inclined to each other at, an angle called angle of prism and the angle of, refraction is always less than the angle of, incidence and the angle of emergence in the, denser medium. Therefore, the emergent ray is, not parallel to the incident ray., 20. Given, m g = 1.52 , m d = 2 .42, Speed of light in medium, µ, \, , 1, Refractive index of medium, , v g > vd, , 21. When two plane mirrors are placed at 90° to, each other, then the incident and reflected ray, will always be parallel to each other, whatever, may be the angle of incidence., 22. The correct reflected ray is shown as, A, , M, C, , F, , P, , Because light rays incident parallel to the, principal axis goes through focus after the, reflection., , SAMPLE PAPER 7, , (iv) The blood from the Bowman’s capsule, passes through the tubular part of nephron, where useful substances such as glucose,, amino acids, salts and major amount of water, are selectively reabsorbed. The incorrect, options can be corrected as :, (i) Renal artery – Takes pure blood to the, kidneys., (ii) Bowman’s capsule – Collects filtrate from, glomerulus and returns it to the tubules., (iv) Collecting duct – Concentration of urine., , tank filled with dialysis fluid. During the, procedure of dialysis, patient’s blood is passed, through these tubes. As the blood passes, the, waste products from the blood moves into, dialysing fluid by diffusion and the purified, blood is pumped back into the patient’s body.

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190, , CBSE Sample Paper Science Class X (Term I), , 23. The beam of light doesn’t deviate at any point, on passing through lens, which means the, material of lens and medium is same. Hence,, m g = mw, 24. Scattering is the phenomenon in which minute, particles and molecules present in air deflect, the sunlight in all directions., 25. When sodium hydrogen carbonate is heated,, the given reaction take place,, D, , NaHCO 3 ¾® Na 2CO 3 + CO2 + H2O, Heat is required to proceed this reaction., Hence, the reaction is endothermic in nature, and CO 2 gas is evolved., 26. According to graph, D has lowest pH value, which means vinegar has lowest pH but, highest H + concentration because pH is, indirectly proportional to concentration of H +, ions. i.e. lower the pH value, higher is the, concentration of H+ ions., 27. Option (d) is incorrect because the correct, reactivity order of the given metals is, Mg > Al > Zn > Fe > Cu, according to, reactivity series., 28. (i) A : 2, 1, B : 2, 6, \The valency of A and B are 1 and 2 respectively, A, , B, , 1, 2, A2B, , Hence, the formula of compound is correct., (ii) B : 2, 6, C : 2, 5, \ The valency of B and C are 2 and 3, respectively., B, 2, , C, , 3, B3C2, , SAMPLE PAPER 7, , Hence, the formula of (ii) is B 3C 2 and not, B2 C3., (iii) C : 2, 5, D : 2, 2, \ The valency of C and D are 3 and 2, respectively., C, 3, , D, , 2, C2D3, , Hence, the formula of compound is correct., , (iv) E : 2, 8, 5 and F : 2, 8, 8, 2, \The valency of E and F are 3 and 2, respectively., E, , F, , 3, , 2, E2 F3, , The formula of (iv) is E 2F 3 and not EF3., Hence, option (d) is correct., 29. Both (ii) and (iv) are true., The litmus paper shows different colours in, different mediums. In acidic medium it, changes from blue to red and in basic medium,, it changes red litmus to blue., 30. Phenolphthalein turns colourless in acidic, solution and red cabbage juice gives red colour, in acidic medium. So, I is acidic in nature and, have pH< 7., 31. Both A and R are true and R is the correct, explanation of A., Reduction, , MnO2 + 4HCl, , Cl2 + 2H2O + MnCl2, Oxidation, , It is a redox reaction, in which MnO2 gets, reduced into MnCl2 and HCl get oxidised into, H2O, simultaneously., 32. A is false but R is true., Aluminium chloride is acidic salt as it is, formed by the reaction between weak base and, hydrochloric acid (strong acid)., Al(OH)3 + 3HCl ¾® AlCl3 + 3H2O, 33. A is true, but R is false., In a healthy adult, the initial filtrate in the, kidneys is about 180 L daily, but the actual, volume excreted is only a litre a day. Most of, the filterate is passed through urine., 34. A is false but R is true., Virtual image can be seen with naked eyes but, it cannot be obtained on screen. The rays, forming virtual image are appeared to meet, each other., 35. Amphoteric oxides are those oxides which, can show both acidic and basic behaviour,, M and P elements reacts with both acid and, bases and hence, they can form amphoteric, oxides.

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191, , CBSE Sample Paper Science Class X (Term I), , 36. Fishes (pisces) have only two-chambered heart, and the blood is pumped to gills for, oxygenation and passes directly to the rest of, the body., 37. Photosynthesis is a process in which, autotrophs such as green plants use carbon, dioxide and water in presence of sunlight to, synthesis food. In this, CO 2 is reduced to, glucose and water is oxidised to release oxygen., 38. Human excretory system consists of a pair of, kidneys, a pair of ureters, a urinary bladder, and a urethra., 39. When a lens is half covered by black paper,, then the brightness of image is decreased but, full image is obtained on the screen., 40. Given, f1 = - 20 cm, f2 = 10 cm, Total focal length, f is, , Þ, , 1, 1, =, +, f, f1, 1, =, +, -20, , 1, f2, 1, 10, , f = 20 cm, , The combination of these two lenses will act as, converging lens of focal length 20 cm., , Angle of emergence for both the media is same, that of angle of incidence because the ray, emerges out is parallel to incident ray., 45. Given, u = -20 cm and f = - 10 cm, 1 1 1, Using mirror formula, + =, v u f, 1, 1, 1, =+, v, 10 20, Þ, v = - 20 cm, So, the image will be formed at centre of, curvature., 46. Given, f = 30 cm, u = -15 cm, From lens formula,, 1 1 1, 1 1 1, - =, Þ, = +, v u f, v, f u, f +u, fu, 1, Þ, =, Þ v=, v, fu, f +u, \, , é, f, fu ù, v, =, ú, êQv =, u f +u, f + uû, ë, 30, 30, =, =, = +2, 30 - 15 15, , m=, , 41. Trypsin works in the basic medium and pepsin, works in the acidic medium to digest the, proteins in intestine and in stomach,, respectively., , 47. A hollow prism does not show dispersion of, light. Because all colours travel with same, speed in air. So, no spectrum is obtained in, hollow prism., , 42. The arteries, carry the oxygenated blood from, the heart to different body parts, while the, veins carry the deoxygenated blood from the, different body parts back to the heart., , 48. For making wires, elements should be ductile,, electrical conductor and have high melting, point. These, properties are present in A, element only., , Since, the blood emerges from the heart under, high pressure. So, the force that blood exerts, against the wall of a vessels is more in arteries, and less in veins., , 44. As the angle of refraction in medium Q is, smaller than medium P. So, medium Q is the, denser medium than medium P. Speed of light, depends on the refractive index of medium., Hence, speed of light in medium P is greater, than speed of light in medium Q., , 50. The given salts are ionic compounds which, have very high melting and boiling points as a, large amount of energy is required to break the, strong inter-ionic attraction., 51. CCl 4 is covalent in nature. Hence, it will not, conduct electricity. Ionic compounds are good, conductors of electricity., 52. The melting point and the boiling point of, ionic compound is high, hence, P and S are, ionic compound., , SAMPLE PAPER 7, , 43. Given, u = - 27 cm, f = - 18 cm, 1 1 1, By mirror formula, + =, v u f, -1, 1, 1, 1, =+, =, Þ, v, 18 27 54, Þ, v = - 54 cm, , 49. All the salts are ionic compounds. They are, hard crystalline solids having high melting, point due to the strong forces of attraction, between the positive and negative ions., They are also brittle. Hence, option (d) is, correct.

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192, , CBSE Sample Paper Science Class X (Term I), , 53. The labels A, B and C indicates food particle,, nucleus and food vacuole, respectively., 54. The labelled part Y represents process of, egestion., 55. The labelled X is pseudopodia, which is, temporary finger-like projections on the cell wall, which helps in ingestion of the food., , SAMPLE PAPER 7, , 56. Statement (i) and (iii) are true for the Amoeba., The food is taken in by the entire surface., The remaining undigested food material is, removed by the cell membrane, which ruptures, suddenly at any places and eliminates out the, undigested food, i.e. egestion., The incorrect statements can be corrected as, ● The pseudopodias are the temporary structures, on the cell surface of amoeba., ● Within the vacuole, complex substances are, broken down into simpler ones which then, diffuse into the cytoplasm., , 57. Normals should be drawn on the top side of, the outlines near their left end not right end., The two pins to be fixed vertically on incident, rays must be suitable distance apart not, 1 cm apart., So, the guidelines B and D need to be, corrected and modified., 58. Two refractions occur on passing through a, glass slab, one at upper interface of air and, glass and other at lower interface of glass and, air., 59. The angle of refraction must be less than, angle of incidence and angle of emergence, i.e., Ðr < 30°, also Ð r < 45°., The angle of emergence is always equal to, angle of incidence i.e., Ð i = Ð e., 60. Angle of incidence is always equal to angle, of emergence and angle of refraction is less, than angle of incidence for glass slab.

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SAMPLE PAPER 8, SCIENCE, A Highly Simulated Practice Questions Paper, for CBSE Class X (Term I) Examination, , Instructions, (i) This paper is divided into three Sections:, (a) Section A – Contains 24 questions. Attempt any 20 questions., (b) Section B – Contains 24 questions. Attempt any 20 questions., (c) Section C – Contains 12 questions. Attempt any 10 questions., (ii) Each questions carries 0.80 mark., (iii) There is NO negative marking., Maximum Marks : 40, Time allowed : 90 Min., , Roll No., , Section A, Section-A consists of 24 questions. Attempt any 20 questions from this section. The first attempted 20, questions would be evaluated., , 1. Heena took 5 mL of copper sulphate solution in a beaker and added 3 mL of, ammonium hydroxide solution to it. What would she observe?, (a) Brown precipitate, (b) Pale blue precipitate, (c) White precipitate, (d) Green precipitate, , 2. Identify the pH range for vinegar in the given pH scale., Red, 0, , 1, , Yellow, 2, , 3, , 4, , 5, , Green, 6, , 7, , (a) 0-2, (c) 7-10, , 8, , 9, , Blue, 10 11 12 13 14, , (b) 3-6, (d) 11-14, , 3., Metal, Dil. HNO3, , Metal salt, , Gas, , Which of the following two combinations are correct?

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194, , CBSE Sample Paper Science Class X (Term I), , Metal, , Gas evolved, , (i) Mg, , Yes, , (ii) Zn, , No, , (iii) Mn, , Yes, , (iv) Ca, , No, , (a) (i) and (ii), (c) (i) and (iii), , (b) (ii) and (iii), (d) (iii) and (iv), , 4. Which of the following is combination reaction ?, (a) MgO + H2 O ¾® Mg(OH) 2, (c) Pb + CuCl 2 ¾® PbCl 2 + Cu, , (b) Zn + FeSO4 ¾® ZnSO4 + Fe, (d) 2H2 O ¾® 2H2 + O2, , 5. The graph given below depicts pH value of different chemicals., 14, 12, 10, pH, 8, 6, 4, 2, 0, , B, , D, , A, C, , Chemicals, , Which of the following produces the least number of hydrogen ions in a solutions?, (a) A, (b) B, (c) C, (d) D, , 6. In the given reaction,, Na + Cl ¾® NaCl, Which option in the given table correctly represents the cation and the anion?, Cation, , Anion, , (a), , Na, , +, , Cl -, , (b), (c), , Cl -, , Na +, , Na, , -, , Cl +, , (d), , Cl +, , Na -, , SAMPLE PAPER 8, , 7. The reaction between the outer surface of metal with air, water and chemicals present, in the atmosphere can be categorised as, (a) reduction, (b) combination, , (c) oxidation, , (d) decomposition, , 8. Which of the given options correctly represents the parent acid and the parent base of, common salt?, Parent acid, , Parent base, , (a), , HCl, , (b), , H2CO3, , Ca(OH) 2, , (c), , H3PO3, , CaSO4, , (d), , H2SO4, , NaOH, , NaOH

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195, , CBSE Sample Paper Science Class X (Term I), , 9. Which indicator should be used to judge how strong a given acid or base ?, (a) Olfactory indicators, (b) Synthetic indicators, (c) Natural indicators, (d) Universal indicators, , 10. The silver chloride is kept in dark bottles because, (a) it will evaporates, (b) it’s colour will change to brown, (c) it will decompose by sunlight, (d) it will undergoes redox reaction, , 11. Carefully study the diagram of human circulatory system with labels (i) to (iv). Select, the option which gives correct identification and main function and/or characteristic., Lung capillaries, , Pulmonary, artery to, lungs, , Pulmonary, vein from, lungs, , (i ), , (iii), , (iv), , (ii), , Capillaries in body organs, apart from the lungs, , (a) (i) Pulmonary circulation — It is the blood circulation pathway in which deoxygenated blood, from the body is sent directly to the lungs., (b) (ii) Systemic circulation — It is the circulation of blood in which oxygenated blood is, pumped from heart to the body and deoxygenated blood is returned back to the heart., (c) (iii) Aorta — Carry deoxygenated blood from body to the lungs., (d) (iv) Vena cava — Carry deoxygenated blood from the lungs to the heart., , 12. A plant is kept in the dark for two days. A leaf is used in an experiment to investigate, the effect of two factors on photosynthesis as shown in the diagram., , Green, leaf, Exposed, to light for, 8 hours, , Leaf removed and, tested for starch, , Q, R, , Substance to absorb, carbon dioxide, , SAMPLE PAPER 8, , Cork cut so leaf, can pass through

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196, , CBSE Sample Paper Science Class X (Term I), , What are the colour of Q and R, when the leaf is tested for starch, using iodine solution?, (a), , Q-Blue/black, , R-Brown, , (b), , Q-Brown, , R-Brown, , (c), , Q-Blue/black, , R-Blue/black, , (d), , Q-Brown, , R-Blue/black, , 13. Which of the following part of the human excretory system is under nervous control?, (a) Ureters, (c) Urinary bladder, , (b) Urethra, (d) Kidneys, , 14. The figure given below shows the human digestive system with labels (i) to (iv)., Identify the correct label with its function, , (i ), (iv), (ii), , (iii), , (a) (i)-Salivary glands - They secrete pepsin for the digestion of starch., (b) (ii)-Pancreas - It secretes gastric juices in the small intestine., (c) (iii)-Gall bladder - It stores the bile., (d) (iv)-Liver - It secretes lipase that helps, emulsification of fat., , 15. Identify the phase of circulation which is represented in the diagram of heart given, , SAMPLE PAPER 8, , below. Arrows indicate contraction of the chamber shown., , (a) Blood transferred to right ventricle and left ventricle simultaneously., (b) Blood is transferred to lungs for oxygenation and is pumped into various organs., (c) Blood transferred to right ventricle and right auricle simultaneously., (d) Blood comes from body organs and is pumped into the lungs.

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197, , CBSE Sample Paper Science Class X (Term I), , 16. Observe the diagram of different stages of nutrition in Amoeba., Nucleus, Food particle, (A ), , (B), , Pseudopodia, , Food vacuole, (C), , Food particle, , (D), , Different stages of nutrition in Amoeba, , Match the labelling referred in Column I and correlate it with the Column II., Column I, , Column II, , A, , 1., , During this process, the undigested food is thrown out of the body., , B., , 2., , It is the procces by which Amoeba takes food with the help of finger-like, projections., , C., , 3., , During this process, complex substances are broken down into simple ones, by digestive enzymes., , D., , 4., , In this process, the digested food present in the food vacoule diffuses into, the cytoplasm., , Codes, A, (a) 3, (b) 1, (c) 2, (d) 2, , B, 2, 4, 3, 3, , C, 4, 3, 1, 4, , D, 1, 2, 4, 1, , 17. A ray of light falls normally or perpendicularly on the surface of a mirror. Which of the, , 18. The magnification produced by a convex mirror is always, (a) equal to unity, (b) less than unity, (c) greater than unity, (d) equal to -1, , SAMPLE PAPER 8, , following is not true regarding this?, (a) The angle of incidence for such a ray of light is zero., (b) The angle of reflection for such a ray of light is zero., (c) This ray is reflected back along the same path., (d) The ray of light does not follow law of reflection.

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198, , CBSE Sample Paper Science Class X (Term I), , 19. A ray of light is incident on concave lens as shown, P, 70º, , A, , B, , O, , Principal axis, , Concave lens, , Then, the refracted ray would travel, (a) along OB, (c) undeviated, , (b) along OA, (d) at 20° to the direction of OB, , 20. In an experiment to trace the path of a ray of light passing through a rectangular glass, slab, the correct markings of angle of incidence (i), angle of refraction ( r) and angle of, emergence (e) is shown below in which diagram?, i, , i, , i, , i, , r, , r, (a), , r, , (b), , r, , (c), , (d), , e, , e, , e, , e, , 21. The angle of refraction at point P on the hemispherical flint glass slab is, A, , 60°, , Air, , O, , Flint glass, Air, , P, , B, , (a) 180°, (c) 90°, , (b) 45°, (d) 0°, , 22. Refractive indices of glass for violet, yellow and red colours are m v , m y and m r ,, respectively. Arrange these in correct order of their values., (a) m r < m y < m v, (b) m y < m r < m v, (c) m v < m y < m r, (d) m r < m y > m v, , 23. The line PQ in the ray diagram as shown, represents which optical device?, , SAMPLE PAPER 8, , P, , Q, , (a) Convex lens, (c) Convex mirror, , (b) Concave mirror, (d) Concave lens

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199, , CBSE Sample Paper Science Class X (Term I), , 24. Radha has to do an experiment on determining the focal length of a given concave, mirror by using a distant object. Out of the following set ups available to her, the set up, that is likely to give her the best result is, (a) a mirror holder, a screen holder and a scale, (b) a screen, a mirror holder and a scale, (c) a screen holder and a scale, (d) a mirror holder and a screen holder, , Section B, Section B consists of 24 questions (Sl. No. 25 to 48). Attempt any 20 questions from this section. The first, attempted 20 questions would be evaluated., , 25. Two reactions are given below?, Reaction A :, , CH 4 ( g) + 2O2 ( g) ¾®, Methane, , Oxygen, , CO2 ( g) + 2H 2O( g) + Heat, Carbon dioxide, , Water, , Reaction B : 6CO 2 ( aq) + 12H 2O( l) ¾Sunlight, ¾¾, ¾® C 6H 12O 6 + 6O 2 + 6H 2O, Chlorophyll, , Glucose, , Identify the correct option from the given table which represents the type of reactions, occurring in reaction A and B respectively?, Exothermic, , Endothermic, , (a), , 3, , 3, , (b), , O, , 3, , (c), , 3, , (d), , O, , O, O, , 26. Salman collected four samples of water from four different water bodies of his village., He recorded the pH value of different sample as, 14, 12, 10, pH 8, 6, 4, 2, 0, , A, , B, , C, , D, , Which water body have pH value similar to distilled water?, (a) A, (b) B, (c) C, , (d) D, , 27. A student performed the following four experiments., FeSO4(aq), , FeSO4(aq), , Al, , Fe, , Zn, I, , FeSO4(aq), , II, , Cu, III, , Which of the following observation is correct?, (a) The displacement reaction occurs in all experiments except III, (b) The solid deposition is observed in I, II and III experiments, (c) The solid deposition is observed in I and II experiment, (d) The displacement reaction is observed in IV experiment, , IV, , SAMPLE PAPER 8, , FeSO4(aq)

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200, , CBSE Sample Paper Science Class X (Term I), , 28. The table shown below have elements with their electronic configuration., Elements, , Electronic configuration, , A, , 2, 8, 1, , B, , 2, 8, 2, , C, , 2, 8, 7, , D, , 2, 8, 5, , Identify the elements that form an ionic compound from the above given substances., (a) A, B, (b) B, C, (c) A, B, D, (d) A, C, , 29. Seerat observed that when washing soda is scrubbed on the stain of curry, the stain, becomes reddish-brown. But when it is washed with lemon juice it becomes yellow, again. What might be the reason for our observation?, I. Washing soda is basic in nature., II. Washing soda is acidic in nature., III. Turmeric gives reddish tinge in bases., IV. Turmeric gives reddish tinge in acids., (a) I and II, (b) I and III, (c) II and III, (d) III and IV, , 30. A metal rod (A) was dipped in coloured solution (B). After sometime, it was observed that, the metal rod starts dissolving in the solution and the solution starts fading its colour. A, coloured precipitate (C) was seen at bottom of beaker. Identify (A), (B) and (C)., A, , B, C, , SAMPLE PAPER 8, , (a) A = Zn, B = FeSO4 , C = Fe, (c) A = Ag, B = CuSO4 , C = Cu, , (b) A = Cu, B = Al 2( SO4 ) 3 , C = Al, (d) A = Fe, B = ZnSO4 , C = Zn, , Direction (Q. No. 31 to 34) Consist of two statements – Assertion (A) and Reason (R). Answer these, questions selecting the appropriate option given below :, (a) Both A and R are true and R is the correct explanation of A., (b) Both A and R are true, but R is not the correct explanation of A., (c) A is true, but R is false., (d) A is false, but R is true., , 31. Assertion Food materials are often packed in air-tight container., Reason The oxidation of fats and oils of food material leads to rancidity., , 32. Assertion Tooth decay starts when the pH of mouth is lower than 5.5., Reason The bacteria present in the mouth produce acids on reacting with food that, remains in the mouth after eating cause tooth decay., , 33. Assertion Plant can survive without separate respiratory organs., Reason Each part of plant takes care of its own gas exchange needs.

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201, , CBSE Sample Paper Science Class X (Term I), , 34. Assertion Higher the refractive index of prism material, lower is the angle of deviation., Reason The angle of deviation is inversely proportional to the angle of prism., , 35. The table given below shows the reaction of a few metals with different salt solution., Element, , CuSO 4, , FeSO 4, , ZnSO 4, , Zn, , 3, , 3, , Cu, , O, , O, , O, O, , Al, , 3, , 3, , 3, , On the basis of above data, the order of the reactivity of metal is, (a) Zn > Al > Cu, (b) Al > Cu > Zn, (c) Cu > Zn > Al, (d) Al > Zn > Cu, , 36. The correct path of lymph flow is, (a) lymphatic capillaries ® lymph vessels ® veins, (b) lymphatic, capillaries ® lymph vessels ® arteries, (c) veins ® lymph vessels ® lymphatic capillaries, (d) arteries ® lymph vessels ® lymphatic capillaries, , 37. Root pressure is maximum when, (a) transpiration is very low and absorption is very high, (b) transpiration is very high and absorption is very low, (c) Both transpiration and absorption are very high, (d) Both transpiration and absorption are very low, , 38. Which of the following equation is the summary of photosynthesis?, (a) 6CO2 + 12 H2 O ¾® C6 H12 O6 + 6O 2 + 6H2 O, (b) 6CO2 + H2 O + Sunlight ¾® C6 H12 O6 + O2 + 6H2 O, (c) 6CO2 + 12 H2 O + Chlorophyll + Sunlight ¾® C6 H12 O6 + 6O2 + 6H2 O, (d) 6CO2 + 12H2 O + Chlorophyll + Sunlight ¾® C6 H12 O6 + 6CO2 + 6H2 O, , 39. If the focal length of concave lens is - 50 cm, then it means the lens has a, (a) power of - 2 D, (c) power of + 2 D, , (b) power of + 0.02 D, (d) power of - 0.02 D, , 40. The image formed by a concave mirror of focal length 15 cm is observed to be virtual,, erect and larger than the object. Where should be the position of the object?, (a) More than 30 cm in front of the mirror, (b) 30 cm in front of the mirror, (c) Less than 15 cm in front of the mirror, (d) Between 15 cm and 30 cm in front of the mirror, organisms., (a) Aerobic respiration and anaerobic respiration, (b) Respiration and breathing, (c) Fermentation and breathing, (d) None of the above, , 42. Which of the following events will be affected if bile juice is not secreted?, (a) Activation of pancreatic enzyme, (c) Breaking down of protein molecules, , (b) Breaking down of starch, (d) Activation of gastric enzyme, , SAMPLE PAPER 8, , 41. Name the two ways in which glucose is oxidised to provide energy in various

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202, , CBSE Sample Paper Science Class X (Term I), , 3, 2, refractive index of glass relative to diamond will be, 5, 1, 5, (b), (c), (a), 2, 4, 8, , 43. The refractive index of glass w.r.t. air is and that of diamond w.r.t. air is, (d), , 12, . The, 5, , 5, 18, , 44., , 2F, , F, Screen, , Suhani covered one-half of a convex lens with a black paper and observed the following, I. This lens produces a complete image of the object., II. The image forms on same side of object., III. Brightness of the image decreases, IV. Image formation depends upon the size of a lens., Which one of the above statements are incorrect?, (a) (I) and (III), (b) (II) and (III), (c) (II) and (IV), , (d) (I) and (IV), , 45. In the following diagram, light is travelling through different media. It is noted by a, scientist that Ð i for both cases is same but Ð r is different., 30º, , 30º, , Air, Medium 1, , Air, Medium 2, , 45º, 10º, , Which of the following statement would be correct?, (a) Medium 1 is denser than medium 2., (b) Medium 2 is the rarest medium., (c) Medium 1 and medium 2 are essentially same medium., (d) Medium 1 is the rarest medium., , 46. Mohit performed the glass slab experiment using different angles of incidences. He, , SAMPLE PAPER 8, , measured the angle of refraction and emergence in each case and recorded them as, given in the table., S.No., , Angle of incidence, (Ði), , Angle of refraction, (Ðr), , Angle of emergence, (Ðe), , 1, , 30°, , 25°, , 30°, , 2, , 40°, , 45°, , 40°, , 3, , 50°, , 52°, , 54°, , 4, , 60°, , 58°, , 64°, , Which of the observation made by him is correct?, (a) 1, (b) 2, (c) 3, , (d) 4

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203, , CBSE Sample Paper Science Class X (Term I), , 47. The focal length of above lens is 10 cm. Find the location of image., Object, , O, 10 cm, , (a) 10 m from right of lens, (c) 5 cm from right of lens, , (b) 5 cm from left of lens, (d) 10 cm from left of lens, , 48. Four metals, A, B, C and D are reacted with dilute sulphuric acid and water. The table, given below shows the result of experiment., Elements, , Reaction with dil. H 2 SO 4, , Reaction with water, , A, , 3, , 7, , B, , 3, , 7, , C, , 3, , 3, , D, , 7, , 7, , Among four metals, which is the most reactive element?, (a) A, (b) B, (c) C, (d) D, , Section C, This Section C consists of three Cases followed by questions. There are a total of 12 questions in this section., Attempt any 10 questions from this section. The first attempted 10 questions would be evaluated., Case I. All metals do not react with water as the metals placed lower in the reactivity series are less, reacting towards water., A group of students performed an experiment based on reactivity of metal and gas evolved., An experimental set up is shown in the figure. The metal X is used in the given experimental setup, which evolves gas Y in glass jar., , Metal X, Gas Y, Glass wool, slaked, with water, , Water, Gas jar, , Burner, , (a) Zinc, , (b) Copper, , (c) Aluminium, , (d) Platinum, , 50. Identify the gas evolved (Y) in this experiment., (a) CO2, (c) O2, , (b) H2, (d) H2 S, , 51. Which one of the following metal reacts most vigorously with cold water?, (a) Sodium, , (b) Magnesium, , (c) Copper, , (d) Zinc, , SAMPLE PAPER 8, , 49. Identify the metal (X) in this experiment.

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204, , CBSE Sample Paper Science Class X (Term I), , 52. Which of the following does not react with water?, (a) Silver, , (b) Gold, , (c) Lead, , (d) All of these, , Case II. Ram was complaining for the dizziness. So, doctor measured Ram’s blood pressure., Doctor used the given instrument for checking and said that it is not normal. Ram readings came out, to be 150/100 mm Hg. He precribed certain medicines to get it back to the normal., , A, , Rubber cuff, inflated, with air, , Artery, closed, , Sounds, audible in, stethoscope, , Artery, , Sounds, stop, , 53. The device (A) used to measure BP is, (a) electrocardiograph, (c) sphygmomanometer, , (b) pulse recorder, (d) thermometer, , 54. Which of the following reason for low blood pressure?, (a) Constriction of ventricles, (c) Relaxation of arterioles, , (b) Relaxation of ventricles, (d) Constriction of arterioles, , 55. The doctor measured Ram’s blood pressure again after medication and said it is normal, now. The range of Ram’s blood pressure is likely to be, (a) the systolic pressure is 120 mm Hg and the diastolic is 80 mm Hg, (b) the systolic pressure is 80 mm Hg and the diastolic is 120 mm Hg, (c) the systolic pressure is 160 mm Hg and diastolic is 80 mm Hg, (d) the systolic pressure is 180 mm Hg and diastolic is 100 mm Hg, , 56. Which of the following caused by hypertension?, , SAMPLE PAPER 8, , I. Rupture of an artery, III. Increase resistance to blood flow, (a) I and II, (c) III and IV, , II. Internal bleeding, IV. Rupture of veins, (b) I, II and III, (d) I and III, , Case III. Shefali set up an experiment arrangement shown, S is a strong source of white light and L1, is a convex lens. Distance between S and L1 is equal to focal length of lens L1 . So, after refraction, through L1 , the light beam becomes a parallel beam of light. This light beam passes through a, transparent glass tank T containing clear water. Emergent beam of light passes through a circular,, hole C made in a cardboard sheet. A convex lens L2 forms a sharp image of the circular hole on a, screen MN., L1, , M, , L2, C, , S, , f1, , T, , f2, , N, , Then, she added 200 g of sodium thiosulphate and 1-2 mL of concentrated sulphuric acid to the, water.

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CBSE Sample Paper Science Class X (Term I), , 205, , 57. After adding the hypo and concentrated sulphuric acid to the water tank, she observes, (a) colour of solution becomes black, (b) solution becomes milky white, (c) precipitate will form at bottom of tank, (d) solution becomes colloidal, , 58. The phenomenon involved in this experiment is, (a) dispersion of light, (b) scattering of light, (c) refraction of light, (d) recombination of light, , 59. Her friend noted some observations about this demonstration as follows, I. Colour of solution becomes bluish., II. Light is transmitted from the front side of the glass tank facing circular hole ., III. An orange-red spot appears on the screen MN., IV. After sometime, a bright crimson red colour spots on the screen., Which one of the above combinations of statements is correct?, (a) I and III, (b) III and IV, (c) II, III and IV, (d) I, II, III and IV, , 60. Near horizon, the sun appears orange as, (a) all the shorter wavelengths are scattered away, (b) red light gets scattered and reaches the eye of observer, (c) all colours of white light get scattered in all directions, (d) light travels shorter distance relatively, , SAMPLE PAPER 8

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OMR SHEET, , SP 8, , Roll No., Sub Code., , Student Name, , Instructions, Use black or blue ball point pens and avoid Gel & Fountain pens for filling the OMR sheet., Darken the bubbles completely. Don’t put a tick mark or a cross mark, half-filled or over-filled bubbles will not be read, by the software., Correct, , ✔, , ✗, , Incorrect, , Incorrect, , Incorrect, , Do not write anything on the OMR Sheet., Multiple markings are invalid., , 1, , 21, , 41, , 2, , 22, , 42, , 3, , 23, , 43, , 4, , 24, , 44, , 5, , 25, , 45, , 6, , 26, , 46, , 7, , 27, , 47, , 8, , 28, , 48, , 9, , 29, , 49, , 10, , 30, , 50, , 11, , 31, , 51, , 12, , 32, , 52, , 13, , 33, , 53, , 14, , 34, , 54, , 15, , 35, , 55, , 16, , 36, , 56, , 17, , 37, , 57, , 18, , 38, , 58, , 19, , 39, , 59, , 20, , 40, , 60, , Check Your Performance, Total Questions:, Total Correct Questions:, , If Your Score is, , Score Percentage =, , Total Correct Questions, Total Questions, , × 100, , Less than 60%, > Average (Revise the concepts again), Greater than 60% but less than 75% > Good (Do more practice), Above 75%, > Excellent (Keep it on)

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207, , CBSE Sample Paper Science Class X (Term I), , Answers, 1. (b), 11. (b), , 2. (a), 12. (b), , 3. (c), 13. (c), , 4. (a), 14. (c), , 21. (d), 31. (a), , 22. (a), 32. (a), , 23. (a), 33. (a), , 24. (b), 34. (d), , 41. (a), 51. (a), , 42. (a), 52. (d), , 43. (c), 53. (c), , 44. (c), 54. (a), , 5. (d), 15. (a), 25. (a), , 6. (a), 16. (d), 26. (b), , 7. (c), 17. (d), 27. (c), , 8. (a), 18. (b), 28. (d), , 9. (d), 19. (c), 29. (b), , 10. (c), 20. (c), 30. (a), , 35. (d), 45. (d), , 36. (a), 46. (a), , 37. (a), 47. (b), , 38. (c), 48. (c), , 39. (a), 49. (a), , 40. (c), 50. (b), , 55. (a), , 56. (b), , 57. (d), , 58. (b), , 59. (d), , 60. (a), , EXPLANATIONS, 1. CuSO4 + 2 NH4OH ¾® Cu(OH)2 + ( NH4 )2 SO4, Copper, sulphate, , Ammonium, (Pale blue), Ammonium, hydroxide (Copper hydroxide) sulphate, , The reaction between copper sulphate and, ammonium hydroxide produces pale blue, precipitate of copper hydroxide along with, ammonium sulphate., 2. Vinegar (acetic acid) is an edible acid. It’s pH, value is around 2.5., 3. When a metal reacts with dil. HNO3, hydrogen, gas (H2 ) is evolved along with the salt of metal., Mg + dil. HNO3 ¾® Mg(NO3 )2 + H2 ­, (Gas), , Zn + dil. HNO3 ¾® Zn(NO3 )2 + H2 ­, Mn + dil. HNO3 ¾® Mn(NO3 )2 + H2 ­, Ca + dil. HNO3 ¾® Ca(NO3 )2 + H2 ­, 4. A reaction in which two or more reactants, combine to form a single product is called, combination reaction. e.g., MgO + H2O ¾® Mg(OH)2, Reaction (b) and (c) are displacement reaction, whereas reaction (d) is decomposition reaction., 5. The pH value of chemical D is highest among, the others. Its pH value is 10 which means it is, basic in nature., Hence, produces the least number of H + ions, in a solution., , 7. The phenomenon due to which open surface of, the metals are slowly eaten away by the, reaction of air, water and chemicals present in, the atmosphere, is called corrosion. It is a type, of oxidation reaction as metal reacts with, , (Strong (Strong, base), acid), , (Neutral (Water), salt), , 9. Universal indicator is a mixture of several, indicators. It shows different colours at different, concentrations of hydrogen ions in a solution., Hence, it is most suitable to judge how strong a, given acid or base is because it gives different, colours in different concentration of acid and, base., 10. Silver chloride undergoes decomposition in, sunlight. Hence, it is kept in dark bottles., 11. (ii) Systematic circulation is the type of, circulation of blood in which oxygenated, blood is pumped from heart to the body, and deoxygenated blood is returned back to, the heart., Incorrect options can be corrected as :, (i) Pulmonary circulation - It is a blood, circulation pathway that moves blood, between heart and lungs., (iii) Aorta - Carries oxygenated blood from, heart to body., (iv) Vena cava - Carries deoxygenated blood, from body to the heart., 12. For photosynthesis to occur, both sunlight and, CO 2 are required. The part Q of leaf was, covered and not exposed to light and part R, was kept in the absence of CO 2. Thus, both, parts of leaf did not form starch and gave a, negative test for starch. (Note-Iodine solution, gives a positive test for starch and turns, blue-black in colour). Thus, during starch test, with iodine both Q and R turns brown and not, as blue-black. Both the regions lack starch., , SAMPLE PAPER 8, , 6. Metals have a tendency to loose electrons to, form cations (+ ve ions) and non-metals have a, tendency to gain electrons to form anions (-ve, ions)., In case of NaCl, Na + acts as cation and Cl - acts, as anion., , oxygen to form metal oxide which is known as, rust in case of iron., 8. NaCl is also known as common salt. It is, formed by the reaction between strong acid, HCl and strong base NaOH., NaOH + HCl ¾® NaCl + H2O

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208, , CBSE Sample Paper Science Class X (Term I), , 13. The urinary bladder is a muscular structure, that stores the urine until we get the urge to, urinate. It is under nervous control., , is the angle between the emergent ray and the, normal at glass-air interface as shown below, Incident, ray, , 14. (iii) The gall bladder functions as a, concentrating reservoir for bile, which it, delivers to the duodenum., Incorrect options can be corrected as, , Glass, Air, , (i) Salivary glands - They secrete salivary, amylase for the digestion of starch., (ii) Pancreas - It secretes pancreatic juice in the, small intestine., (iv) Liver - It secretes bile juice that acts on large, fat molecules to form smaller globules., 15. Right and left auricle contracts at the same time,, pumping blood to the right and left ventricles., Incorrect statements can be corrected as, Blood is transferred to lungs for oxygenation, and is sent back to heart for transportation to, body parts., Blood transferred to left and right auricle, simultaneously., Blood comes from body organ and enters the, heart., l, , l, , l, , 16. A. Ingestion Amoeba ingests food particle by, forming temporary finger-like projections, called pseudopodia around it. The food is, engulfed forming a food vacuole., B. Digestion Inside the food vacuole,, complex substances are broken down into, simpler ones by digestive enzymes., C. Absorption The digested food present in, the food vacuole diffuses into the cytoplasm., , SAMPLE PAPER 8, , D. Egestion The remaining undigested, material moves to the surface of the cell,, the cell membrane ruptures at any place, and undigested food is thrown out of the, body., 17. When a ray of light falls normally, the angle of, incidence and reflection both are zero and light, ray is reflected back along the same path by, following law of reflection., 18. Images formed by convex mirror are always, diminished. So, magnification is always less, than unity or + 1., 19. When a ray of light is incident on optical, centre, it passes undeviated., 20. The angle of incidence (i) is the angle between, the incident ray and the normal at the air-glass, interface, the angle of refraction (r) is the angle, between the refracted ray and the normal at, air-glass interface and the angle of emergence, , Normal 1, i, , Air, Glass, r Refracted, ray, , e Emergent, ray, Normal 2, , 21. The ray of light passes radially outward from, the surface of hemispherical flint glass slab, so, the angle of incidence and angle of refraction, at the point P is 0°., 22. As we know, wavelength of red is more than, yellow and violet., 1, Refractive index µ, Wavelength, \, , l v < l y < l r Þ mr < my < mv, , 23. The optical device represented by line PQ is, convex lens because the rays become less, divergent after refraction through the lens., 24. Radha requires a screen, a mirror holder and a, scale to determine the focal length of a given, concave mirror by using a distant object., 25. In reaction A, energy is produced in form of, heat. Hence, it is an exothermic reaction., CH4 + 2O2 ¾® CO2 + 2H2O + Heat, In reaction B, energy is absorbed in form of, sunlight. Hence, it is an endothermic reaction., ¾ ¾ ® C 6H 12O6 + 6O2, 6CO2( aq) + 12 H 2O( l ) ¾Sunlight, Chlorophyll, Glucose + 6H O, 2, 26. The pH of water body B is 7 and the pH of, normal distilled water is also 7. Therefore,, option (b) is correct., 27. In experiments I and II, there is solid deposition, because Al and Zn are more reactive than Fe and, in experiment IV, no reaction occur because, Fe, is more reactive than copper (Cu)., 28. Element A has 1 electron to transfer or loose, and C can gain 1 electron fulfil its octet. So, A, transfer one electron to C and make ionic, compound., 29. Both I and III are correct. Turmeric is a natural, indicator which turns red on reacting with, base like washing soda and gives yellow, colour on reaction with acid like lemon juice., 30. Zinc is more reactive than iron, so it can, displace iron from its salt solution by, undergoing displacement reaction and then

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209, , CBSE Sample Paper Science Class X (Term I), , iron will start depositing at the bottom of, beaker., Zn+ FeSO4 ¾® ZnSO4 + Fe, , absorption is input of water into plant. If the, output is low and input is high, the pressure will, be greatest., , (A) Metal rod is zinc rod., (B) Coloured solution is ferrous sulphate., (C) Precipitate is iron., This experiment is based on displacement, reaction., , 38. The summary of photosynthesis is, 6CO2 + 12H2O + Chlorophyll + Sunlight ¾®, C6H12O6 + 6H2O, Photosynthesis is a process by which green, plants makes their own food by using CO2 and, H2O in the presence of sunlight and chlorophyll., , (A ), , ( B), , (C ), , 31. Both A and R are true and R is the correct, explanation of A., The oxidation of food items which contain fats, and oil is known as rancidity. It spoil food and, changes its taste and smell. To prevent, rancidity, food items are stored in air tight, container., 32. Both A and R are true and R is the correct, explanation of A., Bacteria present in our mouth reacts with, sugar and produce acid. This acid cause tooth, decay by decomposing our enamel of tooth., 33. Both A and R are true and R is the correct, explanation of A., Plants do not have specialised respiratory, organ. Each plant part takes care of its own gas, exchange needs through diffusion., 34. A is false , but R is true., Higher the refractive index of the prism, material, greater is the angle of deviation., The angle of deviation is inversely, proportional to the angle of prism., 35. According to reactivity series,, Al > Zn > Cu, Al is more reactive than zinc and copper and, Zn is more reactive than copper. The most, reactive element (Al) shows all displacement, reaction involved in this experiment and least, reactive element (Cu) does not show any, displacement reaction with given salt solution., , 37. Root pressure is the pressure that develops in, the roots of the plants by active absorption of, nutrients from the soil., Roots pressure is maximum when transpiration, is very low and absorption is high because, transpiration is output of water from plant and, , 40. To obtain virtual, erect and larger image of, object from concave mirror, object is placed, between the pole of the mirror and its principal, focus. So, the image should be placed at a, distance less than 15 cm from the mirror., 41. The two ways in which glucose is oxidised to, provide energy in various organisms is, through the aerobic (in the presence of oxygen), and anaerobic (in lack of oxygen) respiration., 42. Bile is digestive juice secreted by the liver. It, plays an important role in the digestion of fats. It, also makes the medium alkaline and activate, lipase. If bile juice is not secreted then activation, of pancreatic enzymes will be affected., 3, 12, 43. Given, a mg = , a m d =, 2, 5, 3, a, mg, 5, d, \, = 2 =, mg = a, m d 12 8, 5, 44. When one-half of a convex lens is covered with a, black paper, this lens produces a complete, image of the object but the brightness of the, image decreases because some part of lens is, blocked and also image formation does not, depend upon the size of a lens. So, statements I, and III are correct, while II and IV are incorrect., 45. As the angle of incidence for both the incident, ray is same, but angle of refraction in medium 1, is more than medium 2. So, medium 1 is the, rarest medium because light ray bends away, from normal more in medium 1 than medium 2., 46. In glass slab experiment,, Ði > Ðr and Ðe = Ði, So, observation 1 is correct., 47. Given, f = - 10 cm, u = - 10 cm, Using lens formula,, 1 1 1, - =, v u f, , SAMPLE PAPER 8, , 36. Lymph flows only in one direction, that is from, tissues to heart. From the intercellular space,, lymph drains into lymphatic capillaries, which, join to form large lymph vessels that finally, open into large veins., The path of circulation of lymph is, lymphatic capillaries ® lymph vessels ® veins, , 39. Given, f = - 50 cm, 100, 100, \Power, P =, ÞP=, = -2D, f ( in cm), - 50

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210, , CBSE Sample Paper Science Class X (Term I), , 1 1 1, 1, 1, = + =, v u f - 10 10, 1 -2 -1, =, =, Þ v = - 5 cm, Þ, v 10, 5, Hence, image is at 5 cm from left of lens., Þ, , 48. Since, C shows reaction with both dilute, sulphuric acid and water, it is considered as, most reactive among others., , 56. High blood pressure or hypertension is, caused by the constriction of arterioles;, which results in increased resistance to blood, flow., It can lead to the rupture of an artery and, internal bleeding., , 49. Zinc do not react with cold or hot water but it, reacts with steam., Thus, metal X is zinc, whereas copper,, aluminium and platinum do not react with, water at all., , 57. After adding the hypo and concentrated, sulphuric acid to the water tank, she, observes the solution becomes colloidal., , 50. H2 gas is evolved in this experiment., , 59. The colour of solution becomes bluish due to, the scattering of wavelengths by minute, colloidal sulphur particles. The colour, transmitted light from the glass tank is at, first the orange-red colour and then, becomes bright crimson red colour on the, screen., , Zn + H2O( g ) ¾®, , Zinc, , Steam, , ZnO + H2( g ) ­, , Zinc oxide, , Hydrogen, , 51. Sodium is the most reactive metal and it, vigorously reacts with cold water., 52. Silver, gold and lead are least reactive metals as, they present at the bottom of the reactivity, series. They do not react with water at all., 53. Blood pressure is measured with an instrument, called sphygmomanometer., 54. Low blood pressure is caused by the constriction, of ventricles., , SAMPLE PAPER 8, , 55. The normal systolic pressure is about 120 mm, of Hg and diastolic pressure is 80 mm of Hg., , 58. The phenomenon involved in this experiment, is scattering of light by colloidal particles., , 60. Near horizon, the Sun appears orange, because all the shorter wavelengths are, scattered away by the particles. Therefore,, the light reaches our eyes is of longer, wavelengths. This gives rise to the reddish or, orange appearance of the Sun.

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SAMPLE PAPER 9, SCIENCE, A Highly Simulated Practice Questions Paper, for CBSE Class X (Term I) Examination, , Instructions, (i) This paper is divided into three Sections:, (a) Section A – Contains 24 questions. Attempt any 20 questions., (b) Section B – Contains 24 questions. Attempt any 20 questions., (c) Section C – Contains 12 questions. Attempt any 10 questions., (ii) Each questions carries 0.80 mark., (iii) There is NO negative marking., Maximum Marks : 40, Time allowed : 90 Min., , Roll No., , Section A, Section-A consists of 24 questions. Attempt any 20 questions from this section. The first attempted 20, questions would be evaluated., , 1. A student took 5 mL of potassium iodide and 5 mL of lead nitrate and mixed together., What would he observe ?, (a) The solution become green, (b) Yellow precipitate was formed, (c) White precipitate was formed, (d) The solution become hot, , 2. Identify the gas A in the following experiment ., Gas A, , Boiling tube, , Red lead, oxide, Burner, , (a) H 2, , (b) CO 2, , (c) O 2, , (d) H 2 O

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212, , CBSE Sample Paper Science Class X (Term I), , 3., , Metal, Dil. H2SO4, , Metal salt, , Gas, , Which of the following two combination are correct ?, , Metal, , Gas evolved, , (i) Zinc, , No, , (ii) Iron, , Yes, , (iii) Magnesium, , No, , (iv) Aluminium, , Yes, , (a) (i) and (iii), (c) (ii) and (iii), , (b) (i) and (iii), (d) (ii) and (iv), , 4. Which of the following represents correct balanced chemical equation?, (a) KI( aq) + Pb(NO3 ) 2 ( aq) ¾® 2KNO 3 ( aq) + PbI 2 ( s), (b) 2KI( aq) + Pb (NO 3 ) 2 ( aq) ¾® 2KNO 3 ( aq) + PbI 2 ( s), (c) KI( aq) + Pb(NO 3 ) 2 ( aq) ¾® KNO 3 ( aq) + PbI 2 ( s), (d) 3KI( aq) + 2Pb(NO 3 ) 2 ( aq) ¾® 3KNO 3 ( aq) + 2PbI 2 ( s), , 5. The graph given below depicts a neutralisation reaction. The pH of a solution changes, as we add excess of sulphuric acid to sodium bicarbonate, 14, , A, B, , 7, pH, value, , C, , D, O Volume of sulphuric, acid added, , Which letter denotes the area of graph where both sulphuric acid and salt are present ?, (a) A, (b) B, (c) C, (d) D, , SAMPLE PAPER 9, , 6. In the reaction of aluminium with copper sulphate solution,, 3CuSO 4 + 2Al ¾® 3Cu + Al 2 (SO 4 ) 3, Which option in the given table correctly represents the substance oxidised and the, reducing agent?, Substance oxidised, Reducing agent, (a) Al, Al, (b) Al, Al 2 (SO 4 ) 3, (c) Cu, Al, (d) CuSO 4, Al

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213, , CBSE Sample Paper Science Class X (Term I), , 7. The chemical reaction between aluminium and oxygen can be categorised as, (a) displacement reaction, (c) combination reaction, , (b) decomposition reaction, (d) double displacement reaction, , 8. Which of the given option correctly represents the parent acid and base of potassium, carbonate?, Parent acid, (a) HCl, (b) H 2 CO 3, (c) H 3 PO 4, (d) H 2 SO 4, , Parent base, KOH, KOH, KSO 4, KSO 4, , 9. Chloroform is stored in dark coloured bottles because, (a) it gets oxidised to phosgene in presence of sunlight, (b) it undergoes redox reaction, (c) it undergoes combination reaction, (d) it is white solid, , 10. Identify the chemical equation which have correct states of reactants and products., (a) 4Na( l) + O 2 (g) ¾® 2Na 2 O( s), (b) NaOH( s) + HNO 3 ( aq) ¾® NaNO 3 (s) + H 2 O( l), (c) 2KClO 3 ( s) ¾® 2KCl (s) + 3O 2 ( g), (d) CuO( s) + H2 ( g) ¾® Cu( l) + H 2 O( g), , 11. Carefully study the diagram of the human digestive system with labels (i) to (iv)., Select the option which gives correct identification and main function and/or, characteristics., , Tongue, , (i ), Oesophagus, (ii), , Diaphragm, Gall bladder, (stores bile), Bile duct, Liver, (iii), , (a), (b), (c), (d), , Large intestine, (Colon), , Anus, , (i)-Buccal cavity – It consists of two major parts duodenum and jejunum, (ii)-Stomach – It consists of gastric glands which secrete HCl, mucus and pepsin, (iii)-Pancreas – It is present just in front of stomach and secretes bile, (iv)-Small intestine – It is the shortest part of the alimentary canal, which is site of, carbohydrate’s digestion only., , SAMPLE PAPER 9, , Appendix, , (iv)

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214, , CBSE Sample Paper Science Class X (Term I), , 12. Identify the option that indicates the correct labelling for (i), (ii) and (iii)., (ii), , (iii), , (i ), , (a), (b), (c), (d), , (i)-Right auricle, (ii) Aorta, (iii)-Pulmonary artery, (i)-Right auricle, (ii)-Pulmonary artery, (iii)-Pulmonary vein, (i)-Right auricle, (ii)-Pulmonary vein (iii)-Aorta, (i)-Right auricle, (ii)-Pulmonary vein, (iii)-Pulmonary artery, , 13. The blood leaving the tissues becomes richer in, (a) oxygen, , (b) water, , (c) carbon dioxide, , (d) haemoglobin, , 14. The figure given below shows a human respiratory system with labels (i) to (iv)., Identify the correct label with its function and/or characteristics., (i ), , (ii), , (iii), , (iv), , (a), (b), (c), (d), , (i)-Nasal passage – It serves as a passageway of air directly into alveoli., (ii)-Cartilagenous rings – They are present in oesophagus and ensure it does not collapse, (iii)-Lungs – They facilitate the exchange of gases, (iv)-Alveoli – They are balloon-like structures lined with hair and mucus to filter the air, from dust and dirt, , 15. Identify the phase which is represented in the diagram of the stomata given below., , SAMPLE PAPER 9, , Guard cells, , Stomatal, pore, Chloroplast, , (a) The guard cell shrinks when water flows out of them causing stomatal pore to close, (b) The guard cells swell when water flows into them, causing the stomatal pore to open, (c) The guard cell shrinks when there is too much water loss, causes stomatal pore to, remains open, (d) The guard cells swell when water flows into them, causing the half opening and half, closing of stomatal pore

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215, , CBSE Sample Paper Science Class X (Term I), , 16. Observe the diagram of human excretory system., , D, , A, , B, , C, , Match the labelling referred in Column I and correlate with the Column II., Column I, , Column II, , A, , 1. It is the temporary reservoir for the urine, , B, , 2. It carries unfiltered blood from heart to the kidneys, , C, , 3. They contain nephrons which are the filtering units, , D, , 4. They connect kidneys with the bladder, , Codes, A B C, (a) 3 4 1, (c) 3 2 4, , D, 2, 1, , A B C, (b) 4 1 2, (d) 3 1 2, , D, 3, 4, , 17. Name a liquid whose mass density is less than that of water but it is optically denser, than water., (a) Kerosene, (c) Liquid glass, , (b) Liquid paraffin, (d) Mercury, , 18. A beam of monochromatic light is incident on the box through the holes A and B and, emerges out of the box through P and Q respectively, as shown, , A, , B, Q, , P, , SAMPLE PAPER 9, , What is inside the box?, (a) A convex lens, (b) A concave lens, (c) A rectangular glass slab, (d) A prism, 19. In an experiment with a rectangular glass slab, a student observed that a ray of light, incident at an angle of 55°, after refraction strikes the opposite face before emerging it, makes an angle of 40° with normal. Which of the following is correct?, (a) Angle of emergence is 50°, (b) Angle of refraction is 40°, (c) Ray goes from denser to rarer medium, (d) Ði = Ðr = 55°

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216, , CBSE Sample Paper Science Class X (Term I), , 20. Which one pair is wrongly matched in given columns ?, (a), (b), (c), (d), , Column I, m=1, Real image, Power = -2 D, Bottom of tank appears to be raised, , 21., , Column II, Plane mirror, Convex mirror, Concave lens, Refraction, , S, i2, A, , B, , R, r1, , r2, Q, , D, , C, , i1, P, , Examine the above figure. What is the net deviation suffered by the ray on passing the, glass slab?, (a) r1 - i1, (b) i2 - r2, (c) zero, (d) i1 - r1, , 22. Choose the correct path of ray by convex lens from the following., (a), , (b), F1, , F2, , F1, , F2, , F1, , F2, , F1, , F2, , (d), , (c), , 23. How much time from sunrise to sunset is lengthened due to atmospheric refraction?, (a) 4 hours, (c) 4 minutes, , (b) 2 minutes, (d) 2 hours, , 24. After tracing the path of the light through a glass prism, a student marked the angle of, , SAMPLE PAPER 9, , incidence (i), angle of refraction ( r), angle of emergence ( e) and angle of deviation ( D) as, shown in figure. The correctly marked angles are, , r, i, , (a) i and r, (c) i and e, , d, , e, , (b) i, r and e, (d) i, e and d

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217, , CBSE Sample Paper Science Class X (Term I), , Section B, Section B consists of 24 questions (Sl. No. 25 to 48). Attempt any 20 questions from this section. The first, attempted 20 questions would be evaluated., , 25. Limestone ¾¾® CaO + X, D, , Identify the correct option from the given table which represents the type of reaction, and gas evolved., (a), (b), (c), (d), , Endothermic, ü, , Gas evolved, , û, ü, , ü, ü, , û, , û, , û, , 26. In which year is concentration of hydrogen ion the lowest ?, 6.00, , pH value, , 5.00, 4.00, 3.00, 2.00, 1.00, 0.00, 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011, Rain pH value, , (a) 2002, , (b) 2006, , (c) 2008, , (d) 2011, , 27. The diagram shows the reaction between metal and dil. acid., , Mg+, dil.HCl, , A, , Zn+, dil.HCl, , Fe+, dil.HCl, B, , C, , Ca+, dil.HCl, D, , Which of the following reaction is observed in the given experiment?, (a) Displacement reaction, (b) Combination reaction, (c) Decomposition reaction, (d) Double displacement reaction, , 28. The table shown below gives information about four substances P, Q, R and S, Melting, point (K), , Solid, , Aqueous, , P, , 390, , Good, , Good, , Q, , 1310, , Poor, , Good, , R, , 1730, , Poor, , Good, , S, , 1160, , Poor, , Poor, , Which of the following will form ionic compound ?, (a) P and Q, (b) Q and R, (c) R and S, , (d) P and S, , SAMPLE PAPER 9, , Electrical conductivity, , Substance

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218, , CBSE Sample Paper Science Class X (Term I), , 29. Neeraj observed that the stain of curry on a white shirt becomes reddish-brown when, baking soda is scrubbed on it, but it turns yellow again when the shirt is washed with, plenty of water. What might be the reason for his observation?, I. Baking soda is acidic in nature., II. Baking soda is basic in nature., III. Turmeric is natural indicator which gives reddish tinge in bases., IV. Turmeric is a natural indicator which gives reddish tinge in acids., (a) I and II, (b) II and III, (c) I and IV, (d) II and IV, , 30. In which of the following setup would the bulb glow?, 6 volt battery, , Bulb, , 6 volt battery, , Switch, , Switch, , Beaker, I., , II., , Glucose solution, Rubber cork, , Rubber cork, , 6 volt battery, , Bulb, Switch, , Beaker, IV., , Nail, , Nail, , Alcohol in water, , Lemon juice, , Rubber cork, , SAMPLE PAPER 9, , (a) (I) and (II), (c) (II), (III) and (IV), , Bulb, Switch, , Beaker, III., , Beaker, , Nail, , Nail, Dilute HCl solution, , 6 volt battery, , Bulb, , Rubber cork, , (b) (I) and (IV), (d) (I), (II) and (IV), , Direction (Q. No. 31 to 34) Consist of two statements – Assertion and Reason. Answer these questions, selecting the appropriate option given below :, (a) Both A and R are true and R is the correct explanation of A., (b) Both A and R are true, but R is not the correct explanation of A., (c) A is true, but R is false., (d) A is false, but R is true., , 31. Assertion The elements which form acidic oxides are metals., Reason Metal oxides gives hydroxide ions in water., , 32. Assertion The elements like carbon and sulphur do not react with dilute acids., Reason Non-metals donate electrons to hydrogen ion of acid.

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219, , CBSE Sample Paper Science Class X (Term I), , 33. Assertion The starch solution in which saliva is added, do not turn blue or black on, putting drops of iodine., Reason The enzyme present in saliva digest the starch., , 34. Assertion As the temperature of a medium increases, the refractive index decreases., Reason When a ray travels from vacuum to a medium, then m is known as the absolute, refractive index of medium., , 35. The table given below shows the reaction of a few elements with HCl and NaOH to, evolve hydrogen gas., Which of these elements can form amphoteric oxides ?, Element, , HCl, , NaOH, , A, , û, , û, , B, , ü, , ü, , C, , ü, , û, , D, , ü, , ü, , (a) A and D, (c) A and C, , (b) B and D, (d) B and C, , 36. Waste products in plants are stored in the form of, (a) tannins, carbohydrates, dry leaves, (b) resins, urea, gums, (c) tannins, essential oils, gums, (d) nitrogen, dry leaves , carbon dioxide, , 37. Which one of the following statement is incorrect?, (a) Organisms grow with time, (b) Organisms must repair and maintain their structure, (c) Movement of molecules does not take place among cells, (d) Energy is essential for life process, , 38. What is common between the alveoli present in lungs and the villi present in the small, intestine?, (a) Both are involved in gaseous exchange, (b) Both are involved in increasing the surface area of their respective organs, (c) Both are involved in absorption of food, (d) Both are involved in circulation of blood, , 39. The focal length of an optical device is 2 m. The power of lens is, (b) 2 D, (d) 50 D, , 40. A ball is placed at 80 cm in front of a plane mirror. The distance between the ball and, its image is, (a) 80 cm, (c) 100 cm, , (b) 40 cm, (d) 160 cm, , 41. Choose the forms in which most plants absorb nitrogen., (a) Proteins, urea and nitrogen, (c) Proteins, nitrates and nitrites, , (b) Urea, atmospheric nitrogen and nitrates, (d) Urea, nitrates and nitrites, , SAMPLE PAPER 9, , (a) 0.5 D, (c) 1 D

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220, , CBSE Sample Paper Science Class X (Term I), , 42. If salivary amylase is lacking in the saliva, which of the following events in the mouth, cavity will be affected?, (a) Proteins breaking down into amino acids, (b) Starchs breaking down into sugars, (c) Fats breaking down into fatty acids and glycerol, (d) Absorption of vitamins, , 43. A spherical converging mirror of radius 30 cm is placed in water. Its focal length in air, and water differs by, (a) 30 cm, (c) zero, , (b) 10 cm, (d) 15 cm, , 44., , M, , P, S, , In the given figure, S is the position of the screen on which a clear image of a distant, object is formed by the mirror M. Some observations from this experiment are, (i) the image formed will be virtual and small in size, (ii) if the object moves closer towards the mirror, the image will also move towards the, mirror., (iii) a virtual image cannot be obtained on screen, (iv) No image is obtained on screen, Which of the following statements is correct ?, (a) (i) and (iv), (b) (iii) and (iv), (c) (i) and (ii), (d) (i), (ii), (iii) and (iv), , 45. In the glass slab experiment four students A, B, C and D did the following, A: kept the eyes far from the glass slab while placing both the pins P3 and P4 ., B: kept the eyes close to glass slab while placing both the pins P3 and P4 ., C: kept the eyes close to the glass slab while placing pin P3 and far from the slab, while, placing pin P4 ., D: kept the eyes far from the glass slab while placing pin P3 and close to the slab, while, placing pin P4 ., °, P1, , SAMPLE PAPER 9, , P2°, , P3°, P4°, , The correct procedure is followed by which student?, (a) A, (b) B, (c) C, (d) D

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221, , CBSE Sample Paper Science Class X (Term I), , 46. An object 2 cm in size is placed 30 cm in front of concave mirror as shown, O, P, F, 15 cm, , What will be the size of the image formed?, (a) -1 cm, (b) -2 cm, (c) 2 cm, (d) 1 cm, , 47. The speed of light in a transparent medium is 0.6 times that of its speed in vacuum., What is the refractive index of medium?, (a) 0.6, (b) 1, , (c) 1.67, , (d) 16.7, , 48. A pencil manufacturing unit tested few elements on the basis of their physical, properties., Properties, , W, , X, , Y, , Z, , Lustrous, , Yes, , No, , No, , Yes, , Brittle, , Yes, , No, , No, , Yes, , Electrical conductivity, , Yes, , No, , No, , No, , High, , Low, , Low, , High, , Melting point, , Which of the above elements were discarded for usage by the company ?, (a) W, X, Y, (b) X, Y, Z, (c) W, X, Z, (d) W, X, Z, , Section C, This Section C consists of three Cases followed by questions. There are a total of 12 questions in this, section. Attempt any 10 questions from this section. The first attempted 10 questions would be evaluated., Case I Rajat is a skilled painter. He mixed a white colured powder compound A with water. The, compound A reacted vigorously with water to produce a compound B and large amount of heat., Then, Rajat used the compound B for white washing the walls. Customer was not satisfied with, Rajat’s work as walls were not shining. But Rajat guaranteed him that the walls would shine after, 2-3 days. And after 3 days of whitewash, the walls become shiny., , Compound A, , 49. Name the compound A that Rajat mixes with water., (a) Calcium, (c) Calcium carbonate, , (b) Calcium oxide, (d) Calcium hydroxide, , 50. Name the compound B that Rajat got after mixing A with water., (a) Calcium, (c) Calcium carbonate, , (b) Calcium oxide, (d) Calcium hydroxide, , SAMPLE PAPER 9, , Water

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222, , CBSE Sample Paper Science Class X (Term I), , 51. What type of reaction has occurred here ?, (a) Decomposition reaction, (c) Double displacement reaction, , (b) Displacement reaction, (d) Combination reaction, , 52. Which of the following reactions is responsible for shiny appearance of the walls ?, (a) CaO + H 2 O ¾® Ca(OH) 2, (b) Ca + CO ¾® CaCO 3, (c) Ca(OH) 2 + CO 2 ¾® CaCO 3 + H 2 O, (d) CaCO 3 + H 2 O ¾® Ca(OH) 2 + CO 2, Case II Respiration is a catabolic process which involves the breakdown of food or complex molecules, into simpler products, with the release of energy. Four students experimented to show that CO 2 is, released during respiration., Given below are four different set-ups, marked as (a), (b), (c) and (d) used by each one of the student to, show that carbon dioxide is released during respiration. Only one of them get the correct results., , KOH, solution, Water, , KOH, solution, Water, , Dry gram seeds, (a), , Boiled gram seeds, (b), , KOH, solution, , KOH, solution, Water, Germinating gram seeds, (c), , Water, Wet and germinated gram seeds, (d), , 53. Germinating seeds are used to demonstrate this experiment, because they carry out, (a) active respiration, (c) fast respiration, , (b) slow respiration, (d) Either ‘a’ or ‘b’, , 54. In which of the experimental setup, the water level will rise up in the bent tube ?, (a) A, , (b) B, , (c) C, , (d) D, , SAMPLE PAPER 9, , 55. Which set up will give the correct result?, (a) Set up with dry gram seeds, (b) Set up with boiled gram seeds, (c) Set up with germinating gram seeds, (d) Set up with wet and germinated gram seeds, , 56. What will happen if KOH solution is not used in the small test tube in the experimental, set up to show CO 2 is released during respiration?, (I) CO 2 will not be produced by seeds., (II) Water level will not rise up in tube., (III) CO 2 will produced in large volume by germinating seeds., (IV) CO 2 produced by the germinating seeds will not be absorbed., (a) (II) and (IV), (b) (I) and (II), (c) (III) and (IV), (d) (I) and (IV)

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223, , CBSE Sample Paper Science Class X (Term I), , Case III Rahul wanted to study the properties of a convex lens. He demonstrated an experiment in, which his set-up is shown as below. He placed the object between F1 and 2F1 on the left side of lens, and draw the image formation on the sheet., A, F2, 2F1 B, , F1, , B¢, , O, , 2F2, , A¢, , When he showed this to his teacher, teacher told him that he committed mistake while tracing the ray, diagram., , 57. Which mistake was done by him in this experiment?, (a) Ray is not correctly traced, (b) Position of image is wrong, (c) Lens is tilted, (d) Direction of travelling of ray is incorrect, , 58. If the ray passing from point O is inclined at 30° with principal axis, then what will, inclined of this ray after passing through lens with principal axis?, (a) 30°, (b) 60°, (c) 0°, (d) 90°, , 59. What will be the height of image when object is of 9 cm in height and magnification is, -3?, , (a) 27 cm, (c) - 3 cm, , (b) 3 cm, (d) - 27 cm, , 60. His friend suggested him same precautions while doing this experiment as follows, (i) The convex lens should be thin and of small aperture for obtaining the distinct, image, (ii) Use a very sharp tipped pencil to draw thin lines to represent incident and, refracted rays., (iii) The principal axis of the convex lens should be horizontal i.e., the lens should be, placed vertically., (iv) To determine the focal length, the distance between the convex lens and the object, should be measured horizontally., Which one of the above combination is correct?, (a) (i) and (iv), (b) (ii), (iii) and (iv), (c) (iii) and (iv), (d) (i), (ii) and (iii), , SAMPLE PAPER 9

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OMR SHEET, , SP 9, , Roll No., Sub Code., , Student Name, , Instructions, Use black or blue ball point pens and avoid Gel & Fountain pens for filling the OMR sheet., Darken the bubbles completely. Don’t put a tick mark or a cross mark, half-filled or over-filled bubbles will not be read, by the software., Correct, , ✔, , ✗, , Incorrect, , Incorrect, , Incorrect, , Do not write anything on the OMR Sheet., Multiple markings are invalid., , 1, , 21, , 41, , 2, , 22, , 42, , 3, , 23, , 43, , 4, , 24, , 44, , 5, , 25, , 45, , 6, , 26, , 46, , 7, , 27, , 47, , 8, , 28, , 48, , 9, , 29, , 49, , 10, , 30, , 50, , 11, , 31, , 51, , 12, , 32, , 52, , 13, , 33, , 53, , 14, , 34, , 54, , 15, , 35, , 55, , 16, , 36, , 56, , 17, , 37, , 57, , 18, , 38, , 58, , 19, , 39, , 59, , 20, , 40, , 60, , Check Your Performance, Total Questions:, Total Correct Questions:, , If Your Score is, , Score Percentage =, , Total Correct Questions, Total Questions, , × 100, , Less than 60%, > Average (Revise the concepts again), Greater than 60% but less than 75% > Good (Do more practice), Above 75%, > Excellent (Keep it on)

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225, , CBSE Sample Paper Science Class X (Term I), , Answers, 1. (b), 11. (b), 21. (d), , 2. (c), 12. (a), 22. (a), , 3. (d), 13. (c), 23. (c), , 4. (b), 14. (c), 24. (c), , 5. (d), 15. (b), 25. (c), , 6. (a), 16. (a), 26. (c), , 7. (c), 17. (a), 27. (a), , 8. (b), 18. (c), 28. (b), , 9. (a), 19. (b), 29. (b), , 10. (c), 20. (b), 30. (b), , 31. (d), 41. (d), 51. (d), , 32. (c), 42. (b), 52. (c), , 33. (a), 43. (c), 53. (a), , 34. (b), 44. (d), 54. (c), , 35. (b), 45. (a), 55. (c), , 36. (c), 46. (b), 56. (a), , 37. (c), 47. (c), 57. (b), , 38. (b), 48. (b), 58. (a), , 39. (a), 49. (b), 59. (d), , 40. (d), 50. (d), 60. (d), , EXPLANATIONS, 1. When potassium iodide is reacted with lead, nitrate solution, yellow precipitate of lead, iodide is formed. The reaction take place as, 2KI( aq ) + Pb(NO3 )2( aq) ¾® 2KNO 3( aq) + PbI2( s), (Yellow, ppt.), , 2. (c) When red lead oxide is heated strongly, it, forms lead monoxide and oxygen gas, D, , 2 Pb 3O4 ¾® 6PbO + O2 ­, 3. Zinc, iron, magnesium and aluminium are more, reactive than hydrogen. Therefore, undergoes, displacement reaction with dil. H 2SO 4., Hydrogen is displaced by these metals from its, solution (i.e. H 2SO 4)., During this reaction, hydrogen gas is evolved., Zn + H 2SO 4 ¾® ZnSO 4 + H 2 ­, 2 Fe + 3H 2SO 4 ¾® Fe2(SO 4 )3 + 3 H 2 ­, Mg + H 2SO 4 ¾® MgSO 4 + H 2 ­, 2 Al + 3 H 2SO 4 ¾® Al 2(SO 4 )3 + 3 H 2 ­, Hence, option (d) is correct., 4. In equation (b),, 2KI( aq) + Pb(NO 3) 2( aq) ¾®2KNO 3( aq) + PbI2( s), Total no. of atoms of all the elements are equal, on both sides of equation. Hence, it is a, balanced equation., , 6. The reaction of aluminium with copper, sulphate solution is, 3CuSO 4 + 2Al ¾® 3Cu + Al 2(SO 4) 3, The substance which gets oxidised is called, reducing agent. Hence, in the given reaction, Al, is oxidised and acts as reducing agent by, gaining oxygen atoms and forms Al 2(SO 4) 3., , 8. The term ‘parent acid’ and ‘parent base’ are, used to describe the original compounds that, combined to make the salt. So, potassium, carbonate salt can be formed from H 2CO 3, (parent acid) and KOH (parent base)., 2KOH, ¾®, K 2CO3, H2CO3 +, Carbonic acid, (Parent acid), , Potassium hydroxide, (Parent base), , Potassium carbonate, (Salt), , + 2H2O, Water, , 9. Chloroform gets slowly oxidised by air in, presence of light to an extremely poisonous, gas, i.e. carbonyl chloride wihich is also, known as phosgene., Sun light, , CHCl3 + O2 ¾¾¾¾® COCl2, , (Phosgene), , Hence, to avoid the oxidation of chloroform to, phosgene, it is stored in dark coloured bottles., 10. The reaction (c) is balanced and have correct, states of reactant and products., 2KClO 3( s) ¾® 2KCl(s) + 3O 2( g ), 11. (ii) Stomach is a J-shaped part of the, alimentary canal. This serves as, storehouse of food where partial digestion, takes place through the secretion of gastric, glands. Gastric glands secrete HCl, pepsin, and mucus., Incorrect options can be corrected as :, (i) Buccal cavity : It consists of two major, parts, i.e. tongue and teeth., (iii) Pancreas : It is connected to the small, intestine and secretes pancreatic juice., , SAMPLE PAPER 9, , 5. As the pH of acid is below 7, so the letter which, denotes the area of the graph where both, sulphuric acid and salt are present after, addition of excess sulphuric acid to sodium, bicarbonate is D., , 7. The chemical reaction between aluminium, and oxygen is can be written as :, 4Al( s) + 3O 2( g ) ¾® 2Al 2O 3, In this reaction, two reactants, Al and O 2, reacts with each other and form single, product, i.e. aluminium oxide Al 2O 3. Hence,, this reaction is categorised as combination, reaction.

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226, , CBSE Sample Paper Science Class X (Term I), , (iv) Small intestine : It is longest part of, alimentary canal and it is the site of, complete digestion of food into different, components., 12. The correct labelling is, (i)-Right auricle,, (iii) pulmonary artery, (ii) aorta., Right auricle receives deoxygenated blood, from the body. Pulmonary artery carries, deoxygenated blood from the heart to the, lungs. Aorta carries oxygenated blood from the, heart to the body., , 18. Here, the emergent rays are parallel to the, direction of the incident rays. Therefore, a, rectangular glass slab could be inside the box., 19., , 55º, , (i) Nasal passage : It serves as the zone of, conduction of air., (ii) Cartilagenous rings : They are present in, windpipe (trachea) and ensure it does not, collapse., (iv) Alveoli : Balloon-like structures located, inside lungs and these structures, increase the surface area for the exchange, of gases., , SAMPLE PAPER 9, , 15. The opening and closing of the pore is a, function of the guard cells. The guard cells, swell when water flows into them, causing the, stomatal pore to open. Similarly, the pore, closes if the guard cells shrink., 16. The correct matches are as follows., Kidneys (A) has large number of filtration, units called nephrons packed closely together., Ureter (B) connects the kidneys with the, urinary bladder (C) which is the temporary, reservoir for the urine., The waste material is brought to the kidneys, by the renal arteries ( D)., 17. Kerosene is the liquid whose mass density is, less than that of water but it is optically denser, than water., , Q, , B, P, r1, , r2, C, , S, , R, D, , 13. The blood leaving the tissues becomes richer in, carbon dioxide (CO2). When the oxygenated, blood passed through the capillaries, it gives, oxygen to the cells and at the same time,, carbon dioxide produced during respiration, enters into blood., 14. (iii) Lungs are the primary organ of respiration, in humans and other vertebrates. The primary, function of the lungs is to facilitate the exchange, of gases between the blood and the air., Incorrect options can be corrected as :, , A, , Ði = 55 °, [alternate angles], Ðr1 = Ðr2 = 40 °, As, emergent ray is parallel to incident ray,, \, Ði = Ðe = 55 °, Incident ray goes from rarer to denser that’s, why Ði > Ðr., Here,, , 20. Plane mirror produces a magnification of +1,, convex mirror always forms a virtual and erect, image, power of concave lens is always, negative and bottom of tank appears to be, raised due to refraction of light., 21., , S, i2, R, , A, , B, r2, r1, , D, D, , Q, , C, i1, P, , The net deviation suffered by incident ray is D., [opposite angles], \, i1 = D + r1, Þ, D = i1 - r1, 22. The correct path of ray among the given lens, by convex lens is given as, , F1, , F2, , 23. Due to atmospheric refraction, the day is, lengthened about 4 minutes. Because sunrise, occurs two minutes before the actual sunrise, and sun sets 2 minutes after the actual sunset.

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227, , CBSE Sample Paper Science Class X (Term I), , 24. Only angles i and e are correctly marked. The, rest are corrected as shown., , d, i, , r, , r, , e, , does not dissociate completely into free ions., Hence, the bulb will not glow., In (IV) setup, the electrolyte is lemon juice, which contains citric acid (strong acid). So, it, will dissociates into free ions to conduct, electricity. Hence, the bulb will glow., 31. A is false and R is true. The elements which, form acidic oxides are non-metals. Metal, oxides are basic in nature, therefore gives, hydroxide ions in water., , D, , 25. CaCO3 ¾® CaO + CO2 ­, Limestone, , Calcium, oxide, , Carbon, dioxide, , This reaction is endothermic in nature as it, requires heat energy to proceed and CO 2 gas is, evolved in this reaction., 26. The concentration of hydrogen ions is, inversely related to its pH according to the, following expression :, pH = - log[H + ], So, according to graph, the pH value touched, the highest in 2008. Hence, the concentration of, H + is lowest in 2008., 27. Zinc, magnesium, iron and calcium are more, reactive than hydrogen. Therefore, they, displace hydrogen from HCl and undergo, displacement reation., 28. The ionic compounds are crystalline solids and, hard in nature. Hence, they have high melting, point and conduct electricity in aqueous, solution., So, according to the information given in table,, Q and R substances have high melting points, and good conductor of electricity in aqueous, solution. So, Q and R are ionic compounds., 29. Both (II) and (III) reasons are correct. Baking, soda is basic in nature because when it mixes, with an acid, it changes pH level. Therefore, it, is basic in nature. In basic medium, turmeric, gives reddish tinge. Hence, the stain of, turmeric turns red on scrubbing with baking, soda., , 33. Both A and R are correct and R is the correct, explanation of A., On putting few drops of iodine in starch, solution containing saliva, no blue/black colour, is observed because of the enzyme, i.e. salivary, amylase which is present in saliva and breaks, down the starch molecule into sugar., 34. Both A and R are true but R is not correct, explanation of A., As the temperature of medium increases its, density decreases due to separation of, molecules and hence the refractive index, decreases. When a ray travels from vacuum to, a medium, then the refractive index of that, medium (m ) is the absolute refractive index of, that medium., 35. Amphoteric oxides are those oxides which, shows the properties of both acid and bases., So, the elements B and D form amphoteric, oxides as they react with both HCl and NaOH, to evolve H 2 gas., 36. Plants give off gaseous wastes like CO 2 and O 2, through stomata and lenticels during, respiration and photosynthesis. Other waste, products include gums, resins, tannins,, essential oil, etc., 37. In multicellular organisms, movement of the, molecules occurs between the cells also. The, movement of materials (molecules) in and out, of the cells is carried out by a number of, methods like diffusion and osmosis., Depending upon the energy requirements,, these can be active or passive., The growth of a living organism starts with the, division of its cells. All living things have an, organised structure, which if breaks down, leads to various diseases, disorders and even, death., Therefore, the living things have to repair and, maintain their structures through various, , SAMPLE PAPER 9, , 30. In (I) setup, the electrolyte is dil. HCl solution, which can produce free ions on dissociation in, water to conduct electricity., In (II) setup, the electrolyte is glucose solution, which does not conduct electricity as it does, not dissociate into free ions in water. Hence,, the bulb will not glow., In (III) setup, the electrolyte is alcohol, dissolved in water which does not conduct, electricity because it is very weak acid and, , 32. A is true and R is false. Non-metals accept, electrons while metal donate electrons to, hydrogen ion of acid.

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228, , CBSE Sample Paper Science Class X (Term I), , processes. These life processes require energy, which is obtained from food., 38. The villi are present in the inner lining of the, small intestine, while alveoli are present in, the lungs. Both are involved in increasing the, surface area of their respective organs. Villi, facilitates nutrient absorption, while alveoli, facilitates rapid exchange of oxygen and, carbon dioxide., 1, 39. Here, f = 2 m Þ P =, f, 1, Þ, P = = 0.5 D, 2, 40. The distance between object and image in, case of plane mirror is,, D = 2 ´ distance of object from mirror, = 2 ´ 80 = 160 cm, , 47. As we know that,, c, m=, v, Given, v = 0.6 c, c, 1, \, » 1.67, m=, =, 0.6 c 0.6, 48. The elements X, Y and Z were dicarded for, usage by the pencil company because for pencil, manufacturing graphite is used which is brittle,, lustrous, good conductor of electricity and have, high melting point and W has all these, properties. Hence, W is not discarded among the, others., , 41. Plants need nitrogen for the process of, protein synthesis. However, they cannot, utilise nitrogen as it is. It is converted into, inorganic form as nitrate and nitrite and in, organic form as urea by the action of various, microorganisms. It is then taken up by the, plants for various processes., , 49. Rajat mixed calcium oxide with water which, produces calcium hydroxide and heat., CaO+ H2O ¾®, CO(OH)2 + Heat, , 42. The enzyme salivary amylase is present in, the mouth . This enzyme breaks the starch, molecules in the food into maltose. The, absence of this enzyme, thus affects the, breakdown of starch into simpler sugar, molecules., , 51. When calcium oxide mixed with water,, they combines and form calcium hydroxide., CaO + H 2O ¾® Ca(OH) 2 + Heat, , 43. The focal length of spherical mirror doesn’t, depend on the surrounding medium., 44. The mirror is convex, so the image formed, will be virtual, erect and small in size. If the, object moves closer to mirror, then the image, will also move closer to the mirror. As the, image formed by this is virtual so it cannot, be obtained on screen., 45. The eyes must be kept far from the glass slab, while placing both the pins P3 and P4., , SAMPLE PAPER 9, , Þ, v = -30 cm, Image will be formed at centre of curvature, real, and inverted and of the same size as the object., Hence, the size of image formed is –2 cm., , 46. Here, u = -30 cm, f = -15 cm, ho = 2 cm, Using mirror formula,, 1 1 1, + =, v u f, 1 1 1, = Þ, v f u, 1, 1 2 - 1 -1, =, =, +, =, -15 30 -30 30, , Calcium hydroxide, ( B), , (A), , 50. Calcium hydroxide, CaO + H2O ¾® Ca(OH)2 + Heat, (A), , ( B), , 52. Ca(OH) 2 + CO 2 ¾® CaCO 3 + H 2O, CaCO 3 is responsible for shiny appearance of, walls., 53. Germinating seeds are used to demonstrate, respiration experimentally because they carry, out active respiration and release CO 2 in the, process., 54. The experimental setup ‘C’ will show the rise in, water level in the bent tube because KOH, absorbs carbon dioxide and creates vaccum in, the flask. The air present in the bent tube moves, into the flask. This pulls the water in the bent, tube further up., 55. The setup (C) is the correct set up for the, experiment. In the experiment, moist gram seeds, are taken as they are actively respiring and, releasing CO 2., 56. If KOH is not used in the given experiment, then, there will be no absorption of carbon dioxide, relased by germinating seed., Also, there will be no rise up in the level of, water in the bent tube.

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229, , CBSE Sample Paper Science Class X (Term I), , 57. The position of image was wrongly traced by, Rahul. So, the correct ray diagram that shows, the real position and size of image, corresponding to the position of the object AB, is shown below., A, F2, 2F1 B, , F1 O, , B', 2F2, , A', , 58. When the ray passing from optical centre of, the lens, it passes undeviated as a straight line., So, if the ray initially makes an angle of 30°, with principal axis, hence after refraction, it, makes same angle of 30° with principal axis., , 59. Given, ho = 9 cm, m = -3, Magnification, m =, , hi, ho, , Þ, , hi, 9, , -3 =, , hi = -27 cm, 60. Some precautions are required while, performing this experiment as convex lens is, thin and of small aperture, pencil should be, sharp tipped, lens should be vertical with, principal axis and to determine the focal, length, the distance between the convex lens, and the screen should be measured, horizontally., , SAMPLE PAPER 9

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SAMPLE PAPER 10, SCIENCE, A Highly Simulated Practice Questions Paper, for CBSE Class X (Term I) Examination, , Instructions, (i) This paper is divided into three Sections:, (a) Section A – Contains 24 questions. Attempt any 20 questions., (b) Section B – Contains 24 questions. Attempt any 20 questions., (c) Section C – Contains 12 questions. Attempt any 10 questions., (ii) Each questions carries 0.80 mark., (iii) There is NO negative marking., Maximum Marks : 40, Time allowed : 90 Min., , Roll No., , Section A, Section-A consists of 24 questions. Attempt any 20 questions from this section. The first attempted, 20 questions would be evaluated., , 1. Anam took calcium oxide in an iron container and slowly added water to it., What would she observe?, (a) The pop sound was observed, (b) The white fumes were observed and solution become hot, (c) The hissing sound was produced and solution become hot, (d) The solution become cold, , 2. Identify the gas A is the following experiment., , Gas A, , (a) H2, (c) O 2, , Lime water, Dil. HCl, Na2CO3, , (b) CO 2, (d) Cl 2

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231, , CBSE Sample Paper Science Class X (Term I), , 3., , Metal, Water, , Metal hydroxide, , Gas, , Which of the following two combinations are correct?, Metal, , Gas evolved, , 1., , Zinc, , P, , 2., , Iron, , O, , 3., , Potassium, , O, , 4., , Sodium, , P, , (a) 1 and 2, (c) 2 and 4, , (b) 1 and 4, (d) 3 and 2, , 4. Which of the following correctly represents a balanced chemical equation?, (a) Al 2 O 3 + 3HCl ¾® AlCl 3 + 3H2 O, (b) 2Al 2 O 3 + 6HCl ¾® 2AlCl 3 + 3H2 O, (c) Al 2 O 3 + 3HCl ¾® 2AlCl 3 + 3H2 O, (d) Al 2 O 3 + 6HCl ¾® 2AlCl 3 + 3H2 O, , 5. The graph given below depicts a neutralisation reaction,, HNO 3 + NaOH ¾® NaNO 3 + H 2 O., The pH of a solution changes as we add excess of NaOH to nitric acid., 14, , D, , pH 7, value, , C, B, , A, O, , Volume of NaOH, added, , Which letter denotes the area of the graph where both base and salt are present ?, (a) A, (b) B, (c) C, (d) D, , 6. In the reaction of calcium oxide with hydrochloric acid solution,, Which option in the given table correctly represents the substance reduced and the, oxidising agent ?, Substance reduced, , Oxidising agent, , (a), , CaO, , CaO, , (b), , HCl, , H 2O, , (c), , H 2O, , CaCl 2, , (d), , CaCl 2, , HCl, , SAMPLE PAPER 10, , CaO + 2HCl ¾® CaCl 2 + H 2 O

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232, , CBSE Sample Paper Science Class X (Term I), , 7. The chemical reaction between sodium and oxygen can be categorised as,, (a) displacement reaction, , (b) decomposition reaction, , (c) combination reaction, , (d) double displacement reaction, , 8. Which of the given option correctly represents the parent acid and base of sodium, sulphate ?, (a), (b), (c), (d), , Parent acid, , Parent base, , HCl, H 2 CO 3, H 3 PO 3, H 2 SO4, , NaOH, K(OH) 2, NaSO4, NaOH, , 9. What happens, when zinc reacts with dilute sulphuric acid ?, (a) Red coloured gas is evolved with sweet smell, (b) Green coloured gas is evolved with foul smell, (c) Colourless and odourless gas is evolved which burns with a pop sound, (d) Colourless, pungent smell is evolved which burns with a pop sound, , 10. The ant sting can be cured by rubbing soap on the affected area because, (a) it contains citric acid which neutralises the effect of formic acid, (b) it contains sodium hydroxide which neutralises the effect of formic acid, (c) it contains magnesium hydroxide which neutralises the effect of formic acid., (d) None of the above., , 11. Carefully study the diagram of the human circulatory system with labels (i) to (iv)., Select the option which gives correct identification and main function and/or, characteristics., (i), (ii), (iii), , (a) (i)-Right auricle ® It contracts and the blood moves to the vena cava., (b) (ii)-Left auricle ® It contracts and the blood moves to the pulmonary artery., (c) (iii)-Right ventricle ® It contracts and the blood moves to the left ventricle., (d) (iv)-Left ventricle ® It contracts and the blood moves to the aorta., , 12. Which structures contains muscles that contracts when breathing in?, , X, , Bronchus, Cut end of rib, Lung, , (a) Only X, , (b) X and Y, , heart, , SAMPLE PAPER 10, , (iv), , Z, Y, , (c) Y and Z, , (d) X, Y and Z

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233, , CBSE Sample Paper Science Class X (Term I), , 13. Gastric digestion takes place efficiently in, (a) acidic medium, (b) alkaline medium, (c) neutral medium, (d) highly alkaline medium, , 14. The figure given below shows diagram of human excretory system with labels (i) to, (iv). Identify the correct label with its function., (i), , (ii), (iii), (iv), , (a) (i) Renal artery - Carries purified blood away from the kidney., (b) (ii) Renal vein - Carries blood to the kidneys along with nitrogenous waste materials., (c) (iii) Ureter - Carries urine to the urinary bladder., (d) (iv) Aorta - Carries deoxygenated blood to the kidneys, , 15. Identify the correct statement regarding the human digestive system., Mouth/Buccal cavity, Salivary glands, , Oesophagus (food pipe), , Tongue, Stomach, Liver, Pancreas, Diaphragm, , Gall bladder, (stores bile), , Large intestine, (colon), Rectum, , Small intestine, , (a) The HCl creates an acidic medium that facilitates the action of enzyme pepsin, (b) The length of small intestine differ in various animals depending upon their habitat, (c) The finger-like projections present in stomach increases the surface area for absorption, (d) The end products of digestion of food are glycerol, starch, amino acids and fatty acids, , SAMPLE PAPER 10, , Bile duct, Appendix

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234, , CBSE Sample Paper Science Class X (Term I), , 16. Observe the diagram of human circulatory system., , C, , A, , RA, RV, , LA, LV, , B, , D, , Match the labelling referred in Column I and correlate with Column II., Column I, , Codes, A, (a) 3, (b) 1, (c) 2, (d) 2, , Column II, , A, , 1., , It carries oxygenated blood to the body, , B, , 2., , It carries oxygenated blood from the lungs, , C, , 3., , It carries deoxygenated blood to the heart, , D, , 4., , It carries deoxygenated blood to the lungs, , B, 2, 4, 3, 3, , C, 1, 3, 4, 1, , D, 4, 2, 1, 4, , 17. In torches, search lights and head lights of vehicles, the bulb is placed, (a) between the pole and the focus of the reflector, (b) very near to the focus of the reflector, (c) between the focus and centre of curvature of the reflector, (d) at the centre of curvature of the reflector, , 18. Light source placed at a distance shoots a beam of light parallel to principal axis of a, , SAMPLE PAPER 10, , concave mirror and plane mirror as shown., , After the reflection, beam of light will converge at, (a) focus and infinity respectively, (b) infinity and focus respectively, (c) at radius of curvature and pole respectively, (d) at pole and focus respectively

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235, , CBSE Sample Paper Science Class X (Term I), , 19. Which of the following is the correct measured of the angles of incidence and, emergence by a student?, i, , i, , i, , (a), , (b), , i, (d), , (c), , e, , e, , e, , e, , 20. If a beam of yellow and a beam of green colour are incident at the same angle on the, inclined surface of a prism from air medium and produce angles of refraction y and g, respectively, which of the following is correct?, 1, (a) y = g, (b) y > g, (c) y =, (d) y < g, g, , 21. Consider the refractive indices of; Kerosene 1.63, crown glass 1.49, diamond 2.42., Based on this data, arrange the speed of light through them in increasing order., (a) Speed of light in diamond < speed of light in crown glass < speed of light in kerosene., (b) Speed of light in diamond < speed of light in kerosene < speed of light in crown glass., (c) Speed of light in crown glass < speed of light in Kerosene < speed of light in diamond., (d) Speed of light in kerosene < speed of light in diamond < speed of light in crown glass., , 22., X, , White light, Y, , Prism, , Examine the above figure and state which of the following option is correct?, (a) Colour X is red and colour Y is violet, (b) Colour Y is yellow and colour X is blue, (c) Colour Y is red and colour X is violet, (d) Colour X is blue and colour Y is red, , 23. Which of the following statement is correct regarding the propagation of light of, different colours of white light in air?, (a) Red light moves with fastest speed, (b) Blue light moves faster than green light, (c) All colours of light move with same speed, (d) Yellow moves with fastest speed, the screen (S) using the given concave mirror (M). To determine its focal length, what, distance should he measure to get the focal length of the mirror?, W, S, , W, , (a) MS, , (b) SW, , S, , M, , M, , (c) WM, , (d) MW-SM, , SAMPLE PAPER 10, , 24. A student obtains a sharp image of the distant window (W) of the school laboratory on

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236, , CBSE Sample Paper Science Class X (Term I), , +H O, , 2, 25. Magnesium + O 2 ¾Heated, Magnesium hydroxide, ¾¾, ¾® X ¾¾¾®, , Identify the correct option from the given table which represents the type of reaction., Endothermic, , Gas evolve, , No, Yes, Yes, No, , Yes, No, Yes, No, , (a), (b), (c), (d), , Section B, This section consists of 24 multiple choice questions with overall choice to attempt any 20 questions. In, case more than desirable number of questions are attempted, ONLY first 20 will be considered for evaluation., , 26. In which sample the concentration of H + ion is the highest?, , pH, Value, , A, , (a) A, , (b) B, , B, , C, D, Samples, , E, , (c) C, , (d) E, , 27. Which of the following statement is correct about reactivity series ?, (a) The arrangement of elements in increasing order of reactivity, (b) The arrangement of elements in decreasing order of reactivity, (c) The arrangement of oxides of elements in increasing order of reactivity, (d) The arrangement of elements with water in increasing order of reactivity, , 28. The table shown below gives the information about four elements, A, B, C and D., Substance, , SAMPLE PAPER 10, , A, , Soluble in water, P, , Electrical conductivity, Good, , B, , O, , Bad, , C, , P, , Good, , D, , O, , Good, , Identify the ionic compound from the given substance., (a) A and B, (b) B and C, (c) C and D, , (d) A and C, , 29. A teacher gave two test tubes, one containing water (A) and the other containing, sodium hydroxide solution (B) to the students and asked them to identify the test tube, containing sodium hydroxide solution., The following observation are made by students., I. Litmus paper turns blue in test tube (B)., II. No change on litmus paper in test tube (A)., III. Phenolphthalein turns pink in test tube (B)., IV. Slight change in colour in test tube (A) by adding phenolphthalein.

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237, , CBSE Sample Paper Science Class X (Term I), , Which of the following observations is/are correct ?, (a) I and III, (b) II and III, (c) I, III and III, (d) II, III and IV, , 30., , Colour, , pH, , Red, , 2, , Orange red, , 4, , Orange yellow, , 6, , Green, , 7, , Greenish blue, , 8, , Blue, , 9, , Dark blue, Vioiet, , 10, 10.5, , Equal volume of HCl and NaOH solutions of same concentration are mixed. What will, be the colour and pH of the resulting solution?, (a) Blue, pH = 9, (b) Green, pH = 7, (c) Orange red, pH = 4, (d) Dark blue, pH = 10, Direction (Q. Nos. 31-34) For given questions two statements are given-one labelled Assertion (A) and, the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and, (d) as given below., (a) Both A and R are true and R is the correct explanation of A., (b) Both A and R are true, but R is not the correct explanation of A., (c) A is true, but R is false., (d) A is false, but R is true., , 31. Assertion Magnesium wire is burned in the presence of oxygen., Reason Magnesium acts as a reducing agent., 32. Assertion AlCl 3 is known as basic salt., Reason AlCl 3 is a salt of strong acid and weak base., , 33. Assertion Respiration is an exothermic reaction., Reason During respiration, glucose combines with oxygen to give carbon dioxide and, water. This reaction also release some energy., , 34. Assertion Lateral displacement is the perpendicular distance between incident ray and, the emergent ray., Reason If a wider glass slab is used, then the lateral displacement is also larger., common name and water of crystallisation., Salt, , Common name, , Water of crystallisation, , (i), , Sodium hydroxide, , Caustic soda, , 1, , (ii), , Calcium oxychloride, , Bleaching powder, , 0, , (iii), , Sodium hydrogen carbonate, , Washing soda, , 2, , (iv), , Sodium carbonate, , Soda ash, , 10, , SAMPLE PAPER 10, , 35. The table given below provides the information about some salts, regarding their

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238, , CBSE Sample Paper Science Class X (Term I), , Which of the following are correct about information given in table ?, (a) (i) and (iii), (b) (iii) and (iv), (c) (i) and (ii), (d) (ii) and (iv), , 36. Which of the following processes will not occur if the stomata get blocked?, (a) Transpiration and respiration., (b) Transpiration, photosynthesis and respiration., (c) Respiration, transpiration and transportation., (d) Respiration and photosynthesis., , 37. Digestion begins in the mouth. Which of the following statement is incorrect?, (a) The tongue aids in the digestion of the food, (b) The saliva changes some of the starch present in the food to sugar., (c) The tongue keeps the food in place in the mouth, while the food in being chewed., (d) The digestive juices can react more easily with food when chewed, , 38. How does the kidney dialysis machine function like a healthy kidney?, (a) It deaminate excess amino acids to form urea, (b) It regulates blood concentration, (c) It removes nitrogenous waste products from the blood, (d) It regulates the production of RBCs, , 39. If m 21 and m 31 be the refractive indices of medium number 2 and 3, respectively with, respect to medium 1, then the value of refractive index of medium 3 with respect to, medium 2 is,, m, m, (a) m 21 + m 31, (b) 21, (c) 31, (d) m 21 ´ m 31, m 31, m 21, , 40., , The above lenses have focal length - 50 cm and 10 cm. They are combined to form a, combination. This combination becomes, (a) diverging lens of power 60 D, (b) converging lens of power -25 D, (c) diverging lens of power - 40 D, (d) converging lens of power 0.08 D, , SAMPLE PAPER 10, , 41. Plants get rid of solid and liquid waste by, (a) shedding of leaves, peeling of bark and decoloration of leaves, (b) peeling of bark, falling of fruits and transportation, (c) falling of fruits, shedding of leaves, peeling of bark, (d) falling of fruits, maturing of plant, transportation, , 42. The left ventricle of the heart is thicker wall than the right ventricle, (a) because it contains more blood, (b) so that more deoxygenated blood can reach every part, (c) because when blood is pumped, a strong pressure acts on it, (d) because it receives blood from the lungs

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239, , CBSE Sample Paper Science Class X (Term I), , 43., A, Ray 1, Ray 2, , Ray 1, Ray 2, , Ray 3, , Ray 3, Prism, , A student observes the diagram of path of a ray of light passing through a glass prism., He finds that for all angles of incidence the ray of light bends., Which of the following is correct about it?, I. The ray bends towards the normal while entering into the prism and away from the, normal while emerging out of the prism., II. The ray bends away from the normal while entering into the prism and towards the, normal while emerging out of the prism., (a) Only I, (b) Only II, (c) I and II, (d) Neither I nor II, , 44. A 10 mm long pin is placed vertically in front of a concave mirror. A 5 mm long image, is formed at 30 cm in front of the mirror. The focal length of this mirror is, (a) - 30 cm, (b) - 40 cm, (c) -15 cm, (d) - 20 cm, , 45., Candle, 3m, Wall, , The height of above candle is 3 cm and it is placed at a distance of 3 m from a wall., How far from the wall must a concave mirror be placed in order to get a 9 cm high, image on the wall?, (a) 450 cm, (b) 350 cm, (c) 275 cm, (d) 200 cm, , A child is standing in front of a plane mirror of length 58 cm. He noticed that he sees, his full image in mirror. What is the height of child?, (a) 1.32 m, (b) 1.16 m, (c) 1 m, (d) 0.58 m, , SAMPLE PAPER 10, , 46.

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240, , CBSE Sample Paper Science Class X (Term I), , 47., m1, m2, , q1, , q3, , q2, , While looking at the above ray diagrams, Uma concluded the following, (I) Medium 2 is denser than medium 1., (II) Bending of light depends upon the refractive index of medium., (III) Angle q 3 is the critical angle for medium 1, (IV) This is the phenomenon of total internal reflection, Which one of the above statements are incorrect?, (b) (II) and (IV), (d) (II), (III) and (IV), , (a) (III), (c) (III) and (IV), , 48., Element, , Malleable, , Ductile, , Lustre, , A, , Yes, , Yes, , Yes, , B, , No, , No, , Yes, , C, , Yes, , No, , Yes, , D, , Yes, , No, , Yes, , Which of the above elements can be used for making jewellery ?, (a) A and B, (c) D Only, , (b) B and C, (d) A Only, , Section C, This section consists of 6 multiple choice questions with an overall choice to attempt any 5. In case more, than desirable number of questions are attempted, ONLY first 5 will be considered for evaluation., , SAMPLE PAPER 10, , Case I An indicator is used to confirm the presence of an acid, a base or a neutral solution., The pH scale measures how acidic or basic a substance by making use of hydrogen ion concentration, in them. The table given below showes the pH value and colour change shown by substance P, Q, R,, S and T by using universal indicator., Substance, , pH, , Colour shown by universal indicator, , P, , 6, , Greenish yellow, , Q, , 12, , Navy blue, , R, , 0, , Dark red, , S, , 8.5, , Greenish blue, , T, , 3, , Orange

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241, , CBSE Sample Paper Science Class X (Term I), , Read the above passage carefully and answer the following questions:, , 49. Which of the following is/are true about substance Q?, I. It is the strongest base among the given substance., II. It is used in antacids., III. It turns blue litmus paper to red., IV. None of the above, (a) I, II, (b) II, III, (c) I, II, III, (d) Only IV, , 50. Which of the following statement is correct about substance S?, (a) It can be used as baking soda, (b) It is used in fire extinguisher, (c) It turns red litmus paper to blue, (d) All of the above, , 51. Arrange the substance P, Q and T in increasing order of their acidic strength., (a) T < P < Q, (c) Q < P < T, , (b) P < T < Q, (d) P < Q < T, , 52. Which of the following cannot act as an indicator?, (a) Methyl orange, (c) Turmeric, , (b) Methyl yellow, (d) Red cabbage juice, , Case II The figure shown below represents an activity to prove that chlorophyll is necessary for, photosynthesis. During this activity potted plant with variegated leaves is kept in dark room for 3 days., After this, keeps the plant in sunlight for 6 hours. Then, pluck a leaf and dip in boiling water for few, minutes and after that in alcohol. Then, iodine test is performed on the leaf., , (a), , (b), , 53. The part of the leaf which was originally green turns, (b) blue/black, (d) brown, , 54. Why is the plant kept in dark for three days?, (a) To destarch its leaves, (b) To remove all the carbon dioxide, (c) To remove all the oxygen, (d) To remove all the water, , 55. The function of alcohol is to remove, (a) cell wall, (c) water, , (b) starch, (d) chlorophyll, , SAMPLE PAPER 10, , (a) pink, (c) green

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242, , CBSE Sample Paper Science Class X (Term I), , 56. Which of the following steps can be followed for better iodine test?, (i), (ii), (iii), (iv), , Boiling in water., Keeping the plant in dark for more days., Boiling in alcohol., Cutting of leaves., , Choose the correct option., (a) (i) and (ii), (c) (i) and (iii), , (b) (ii) and (iv), (d) (i) and (iv), , Case III. Rohit performs an experiment on determining the focal length of a convex lens. He kept a, lighted candle at one end of table, a screen on its other end and the lens between them as shown in, figure below. The positions of the three are adjusted to get a sharp image of the flame of candle on the, screen., For more information he replaced the flame of candle by a distant lamp on a far away electric pole., Screen, , Candle, (Object), (Image), Lens, , 57. When the source is changed to distant lamp, then the image will be focussed, (a) beyond 2 f, (c) between f and 2 f, , (b) at f, (d) at 2 f, , 58. He noted some observations from this demonstration and concluded the following, (I) As he moves the screen, the image gets focussed beyond 2 f of the lens., (II) The parallel rays originating from a distant object and incident on a convex lens, may not be parallel to its principal axis., (III) As, he changed the source, the size of the image will also get changed, (IV) Size of image will be more after the candle flame was replaced., Which one of the following combination is incorrect from the above statements?, (a) (II) and (III), (b) (I) and (II), (c) (I) and (IV), (d) (II) and (IV), , SAMPLE PAPER 10, , 59. An object 50 cm tall is placed on the principal axis of a convex lens. Its 20 cm tall image, is formed on the screen placed at a distance of 10 cm from the lens. Calculate the focal, length of the lens., (a) 7.14 cm, (b) 5 cm, (c) 20 cm, (d) 6.5 cm, , 60. Which is not the property of convex lens?, (a) It forms a real and inverted image, (b) It gives magnified image, (c) It gives small point sized image, (d) It is used as rear view lens

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OMR SHEET, , SP 10, , Roll No., Sub Code., , Student Name, , Instructions, Use black or blue ball point pens and avoid Gel & Fountain pens for filling the OMR sheet., Darken the bubbles completely. Don’t put a tick mark or a cross mark, half-filled or over-filled bubbles will not be read, by the software., Correct, , ✔, , ✗, , Incorrect, , Incorrect, , Incorrect, , Do not write anything on the OMR Sheet., Multiple markings are invalid., , 1, , 21, , 41, , 2, , 22, , 42, , 3, , 23, , 43, , 4, , 24, , 44, , 5, , 25, , 45, , 6, , 26, , 46, , 7, , 27, , 47, , 8, , 28, , 48, , 9, , 29, , 49, , 10, , 30, , 50, , 11, , 31, , 51, , 12, , 32, , 52, , 13, , 33, , 53, , 14, , 34, , 54, , 15, , 35, , 55, , 16, , 36, , 56, , 17, , 37, , 57, , 18, , 38, , 58, , 19, , 39, , 59, , 20, , 40, , 60, , Check Your Performance, Total Questions:, Total Correct Questions:, , If Your Score is, , Score Percentage =, , Total Correct Questions, Total Questions, , × 100, , Less than 60%, > Average (Revise the concepts again), Greater than 60% but less than 75% > Good (Do more practice), Above 75%, > Excellent (Keep it on)

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244, , CBSE Sample Paper Science Class X (Term I), , Answers, 1. (c), 11. (d), 21. (b), , 2. (b), 12. (b), 22. (c), , 3. (c), 13. (a), 23. (c), , 4. (d), 14. (c), 24. (a), , 5. (d), 15. (a), 25. (b), , 6. (a), 16. (c), 26. (c), , 7. (c), 17. (b), 27. (b), , 8. (d), 18. (a), 28. (d), , 9. (c), 19. (c), 29. (a), , 10. (b), 20. (d), 30. (b), , 31. (a), 41. (c), , 32. (d), 42. (c), , 33. (a), 43. (a), , 34. (b), 44. (d), , 35. (d), 45. (a), , 36. (b), 46. (b), , 37. (a), 47. (a), , 38. (b), 48. (d), , 39. (c), 49. (a), , 40. (d), 50. (d), , 51. (c), , 52. (b), , 53. (b), , 54. (a), , 55. (d), , 56. (c), , 57. (b), , 58. (b), , 59. (a), , 60. (d), , EXPLANATIONS, 1. When calcium oxide reacts with water, it forms, calcium hydroxide and release large amount of, heat which makes the solution hot., CaO( s) + H 2O( l ) ¾® Ca(OH)2( aq), The hissing sound was produced and solution, becomes hot. It is a combination reaction and, exothermic in nature., 2. When dilute HCl is treated with sodium, carbonate, then CO 2 is released. Hence, gas A is, CO 2., HCl + Na 2CO 3 ¾® NaCl + H 2O + CO 2 ­, The carbon dioxide produced turns the lime, water quickly., 3. Iron and zinc do not react either with cold or, hot water. Potassium and sodium reacts, vigorously with water and form oxide and, evolve hydrogen gas. Hence, combination, 2 and 4 are correct., 4. In (d) reaction,, Al 2O 3 + 6 HCl ¾® 2 AlCl 3 + 3 H 2O, The number of atom of all the elements are, equal in number on both sides of equation., 5. Acid and base reacts with each other to form, salt and water. This process known as, neutralisation reaction., , SAMPLE PAPER 10, , Acid + Base ® Salt + Water, As we add base to an acid, the solution will, become basic in nature where pH ranges above, 7. So, D is the correct option., 6. CaO + 2 HCl ¾® CaCl 2 + H 2O, In this reaction, CaO is reduced to CaCl 2 by, removal of oxygen atom. So, the substance that, gets reduced in the reaction is called, , oxidising agent. Hence, CaO is also an, oxidising agent., 7. The reaction between sodium and oxygen is, as follows, 4Na( s) + O 2( g ) ¾® 2Na 2O( g ), In this reaction, sodium and oxygen are, combined to form a single product. Therefore,, it is a combination reaction., 8. Sodium sulphate (Na 2SO 4) is formed by the, reaction between sodium hydroxide (parent, base) and sulphuric acid (parent acid)., 2NaOH + H2SO4 ¾®, (Parent base) (Parent acid), , Na 2SO4 + 2H2O, , 9. Zinc is more reactive than hydrogen, thus, displace hydrogen from its solution to form, ZnSO 4 and evolved hydrogen gas., Zn + dil. H 2SO 4 ¾® ZnSO 4 + H 2 ­, The colourless and odourless gas is evovled, which is hydrogen and it burns with a pop, sound., 10. As the ant sting contains formic acid and to, neutralise this acid, base is rubbed like soap, (sodium hydroxide) on affected area., 11. When the left ventricle contracts, it forces, oxygenated blood into the aorta., The aorta carries the blood to all the body’s, tissues., 12. X shows muscles of diaphragm and Y shows, intercostal muscles. Contraction of these, muscles helps in breathing., 13. Gastric HCI provides an acidic medium, which is essential for the action of gastric, enzymes.

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245, , CBSE Sample Paper Science Class X (Term I), , (i) Renal artery – carries impure blood to, kidney., (ii) Renal vein – carries pure blood out, kidney., (iv) Aorta – delivers oxygenated blood to the, kidney., 15. The hydrochloric acid creates an acidic, medium which facilitates the action of the, enzyme pepsin., Incorrect statements can be corrected as :, ● The length of small intestine differs is, various animals depending on the type of, food they eat., ● The finger-like projections present in, small intestine increases the surface area, for absorption., ● The end products of digestion of food are, monosaccharides amino acids, fatty acids, and glycerol., 16. Pulmonary artery carries deoxygenated, blood to the heart., Pulmonary vein carries oxygenated blood, from lungs to the heart., Aorta carries oxygenated blood from the heart, to the body parts. Vena cava dexygenated, blood from the body parts to the heart., 17. In torches, search lights and head lights of, vehicles, the bulb is placed very near to the, focus of the concave reflector so that the, reflected beam becomes a parallel beam of, light through which we can see upto a longer, distance., 18. After reflection, concave mirror converges, parallel beam of light at its focus and the, focus of plane mirror is at infinity so, it, focuses parallel beams at infinity., , i, , 22. The least deviated ray is of red colour and most, deviated ray is of violet colour of white light, spectrum. If we invert this prism, then the path, of light is shown, , Y, White light, Prism, , So, X corresponds to violet and Y corresponds to, red., 23. All colours of white light move with the same, speed during propagation of light of different, colours in air., 24. He should measure the distance between the, screen S and mirror i.e. MS., As the image of a distant object is obtained at the, focus of concave mirror., The image obtained at screen must be sharp and, then only focus of the mirror can be obtained, accurately., D, 25. Mg + O 2 ¾¾, ® MgO ¾¾® Mg(OH)2, + H2, , In this reaction, heat is required for the, completion of reaction. Hence, the reaction is, endothermic in nature. No gas is evolved in this, reaction., 26. Higher the pH value, less will be H + ion, concentration. The pH value is lowest at C,, hence highest H + ion concentration is present, in C., 27. Reactivity series refers to the arrangement of, metals in the descending or decreasing order of, their reactivities., 28. The ionic compounds, usually soluble in water, and they can conduct electricity. So, A and C, have properties ionic of compound., , e, , SAMPLE, SAMPLEPAPER, PAPER10, 1, , 19. The correct measurement of angle of, incidence and angle of reflection through a, glass slab is shown below,, , 20. As the wavelength of yellow light is more than, green light., 1, Wavelength µ, Deviation, Þ The angle of refraction of yellow light ( y ) is, less than the angle of refraction of green light ( g ), i.e., y < g., 1, 21. As, speed of light µ, refractive index, \, md > mk > m g, Þ, vd < vk < v g, , X, , 14. (iii) Ureter are the narrow tubes that carry, urine from the kidneys to the urinary, bladder.

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246, , CBSE Sample Paper Science Class X (Term I), , 29. Test tube A contains water which is neutral in, nature. Whereas test tube B contains sodium, hydroxide which is basic in nature., The litmus paper turns blue in basic medium, (sodium hydroxide present in test tube B)., Therefore, statement I is correct., The litmus paper gives green colour in neutral, solution (i.e. water present in test tube A)., Therefore, statement II is incorrect., Phenolphthalein turns pink in basic medium, (sodium hydroxide present in text tube B)., Therefore, statement III is correct., Phenolphthalein is colourless solution, on, adding water it remains colourless and show, no change., Hence, statement IV is incorrect., 30. When equal volume of HCl and NaOH, solutions of same concentration are mixed,, then neutral salt and water are formed which, have pH = 7 and show green colour., NaOH + HCl ¾® NaOH + H 2O, This is known as neutralisation reaction., 31. Both A and R are true and R is the correct, explanation of A. Mg burns in the presence, of oxygen., 2 Mg + O 2 ¾® 2 MgO, This reaction is an example of oxidation, reaction. Mg gets oxidised into MgO therefore, acts as reducing agent., 32. A is false, but R is true because AlCl 3 is an, acidic salt as it is a salt of strong acid (HCl) and, weak base (Al(OH)3 )., 33. Both Assertion and Reason are true and, Reason is the correct explanation of Assertion., , SAMPLE PAPER 10, , The reaction in which energy is released is, called as exothermic reaction. During, respiration, some amount of energy is released,, therefore, it is an exothermic reaction., 34. Both A and R true but R is not correct, explanation of A. The perpendicular distance, between the emergent ray and incident ray, when a light passes out of a glass slab is called, lateral displacement., Lateral displacement is due to refraction of light., In a thick glass slab, the perpendicular distance, between emergent ray and incident ray, increases, which in turn increases lateral, displacement., , 35. Caustic soda is sodium hydroxide (NaOH), with no water of crystallisation., Calcium oxychloride is bleaching powder, (CaOCl2 ) with no water of crystallisation., Sodium hydrogen carbonate is baking soda, (NaHCO3 ) with no water of crystallisation., Soda ash is washing soda (Na 2CO3 × 10H2O), with 10 molecules of water of crystallisation., Hence, (ii) and (iv) are correct., 36. Stomata are responsible for gaseous exchange, in the plant. It is also responsible for removing, extra water present in the plants., Therefore, if stomata get blocked, process of, transpiration, photosynthesis and respiration, will not occur., 37. The tongue helps us to taste the food, chew, and swallow the food. It does not acid in, digestion of food., 38. A kidney dialysis machine acts in a similar, way as a normal kidney by regulating the, normal concentration of the blood., The urea and excess mineral salts in the body, diffuses from the patient’s blood across the, selectively permeable walls of the tubules into, the dialysis fluid., 39. Let refractive index of 2nd media w.r.t 1,, m, m 21 = 2, m1, Similarly, m 31 =, , m3, m1, , \ Refractive index of 3rd media w.r.t 2nd, media, m, m 32 = 3, m2, =, , m 31 ´ m 1 m 31, =, m 21 ´ m 1 m 21, , 40. Given, f1 = - 50 cm, f2 = 10 cm, Total focal length,, , 1 1, 1, =, +, f, f1, f2, 1, 1, 2, +, =, -50 10 25, 1 2, P= =, = 0.08 D, f 25, =, , \, , Since, focal length is positive, the lens will be, converging in nature.

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247, , CBSE Sample Paper Science Class X (Term I), , 41. Plants get rid of stored solid and liquid wastes, by shedding of leaves, peeling of bark and, falling of fruits., 42. The left ventricle has thicker wall than right, ventricle because it has to pump the blood, further around the body, and against, higher pressure, compared with the right, ventricle., 43. For all angles of incidence on a glass prism, the, ray bends towards the normal while, entering into the prism as refractive index is, increased, and away from the normal while, emerging out of prism as refractive index is, decreased., 44. Given, v = - 30 cm,, \, , hi = - 5 mm, ho = 10 mm, h, v, m= i = ho, u, , Þ, , u= -, , 50. The substance S could be sodium bicarbonate, having pH value around 8.5. It is used as, baking soda and also used in fire, extinguishers. It is basic in nature, therefore, turns red litmus blue., , -10, ´ - 30 = - 60 cm, -5, Using mirror formula,, , 51. The pH value of P, Q and T are 6, 12 and 3, respectively. The acidic strength is inversely, proportional to the pH value., , 1 1 1, + =, u v, f, , Þ, , f =-, , Lesser the value of pH, more acidic is the, nature of the substance., 60, = - 20 cm, 3, , pH value : T < P < Q, Acidic strength : Q < P < T, , 45. Let u be the object distance from mirror., Then, image distance is ( u + 3 )., v h, As, magnification m = - = i, u ho, ( u + 3 ) -9, Þ, =, u, 3, Þ, u = 1.5 m, u + 3 = 4.5 m, = 450 cm, , H, 2, Given, l = 58 cm, H, 58 cm =, 2, Þ, , l=, , H = 116 cm = 116, . m, , Lesser the pH, more is the acidic strength., 52. Methyl yellow is not an indicator., 53. The part of the leaf which was originally, green (due to presence of chlorophyll) turns, blue-black showing starch is present in this, part., 54. The plant is kept in dark for three days to, destarch its leaves., H, 2, , 55. The boiling alcohol removes chlorophyll and, turns green., 56. Before testing for starch, chlorophyll has to be, removed from the leaf., The presence of chlorophyll interferes with, the starch test. the boiling alcohol removes, chlorophyll., Boiling in water will break the cell wall and, cell membrane making it more permeable to, iodine solution., , SAMPLE, SAMPLEPAPER, PAPER10, 1, , 46. Length of mirror required to see full image =, \, , So, from the given table, element A is having, all these properties and can be used for, making jewellery., , Hence, can be used in antacids. Therefore I, and II are correct., , =, , 1, 1, 1, +, =, - 60 - 30, f, , 48. For making jewellery, the element should be, malleable, ductile and lustrous., , 49. The pH of substance Q is 12, i.e. highest among, the other substances. It is basic in nature., , ho, ´v, hi, , Þ, , 47. As medium 1 is optically rarer than medium, 2, and the bending of light depends upon the, refractive index of medium., The three corresponding diagram are, representation of at different incidence, angles, refraction angle is different. And at a, certain incidence angle (q 2 ) the refracted, angle is 90° and this is the case of total, internal reflection.

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248, , CBSE Sample Paper Science Class X (Term I), , 57. When the source is changed to distant lamp,, then the image will focussed at focus f, because parallel beam is coming from distant, source., 58. The statements II and III are in correct they, are corrected as when the screen moves, the, image will try to focus at f ., The parallel rays originating from a distant, object/source and incident on a convex, lens may not be parallel to its principal, axis., As the source changed to distant source, the, image will become point sized., , SAMPLE PAPER 10, , 59. Given, ho = 50 cm, hi = - 20 cm , v = - 10 cm, h, v, As, magnification, m = i = ho, u, , -20 10, =, 50, u, Þ, u = - 25 cm, 1 1 1, Focal length,, = f v u, 1 æ 1ö, =, - ç- ÷, 10 è 25 ø, =, , =, Þ, , f =, , 1, 1, 7, +, =, 10 25 50, 50, cm = 7.14 cm, 7, , 60. Convex lens can give virtual, real, diminished,, and magnified image. Image formation, depends on the position of object. Convex, mirrors are used as rear view mirrors.