Question 1 :
What does an increase in pH values from 7 to 14 signify?
Question 4 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b19d27273b230584979bae.JPG' />
In the given figure, name the carbon compound.
Question 5 :
Water is a by product when ethanol reacts with sodium. Is it TRUE OR FALSE?
Question 7 :
Give an example of a double displacement reaction other than the reaction of barium chloride with sodium sulphate.
Question 8 :
A solution of a substance 'X' is used for white washing
Write the formula of 'X'.
Question 9 :
Why does the colour of copper sulphate solution change when an iron nail is dipped in it?
Question 10 :
The important feature(s) of fossils which help in the study of evolution is/are
(i)Fossils represent modes of preservation of ancient species
(ii)Fossils help in establishing evolutionary traits among organisms and their ancestors
(iii)Fossils help in establishing the time period in which organisms lived
Question 11 :
Select the statement that describe characteristics of genes :
(i) Genes are specific sequence of bases in a DNA molecule
(ii) A gene does not code for proteins
(iii) In individuals of a given species, a specific gene is located on a particular chromosome
(iv) Each chromosome has only one gene
Question 15 :
What criteria do we use to decide whether something is alive ?
Question 16 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b19cf3273b230584979b73.JPG ' />
In the arrangement shown in above figure there are two coils wound on a non-conducting cylindrical rod. Initially the key is not inserted. Then the key is inserted and later removed . Then
Question 17 :
State TRUE or FALSE. Dry cell battery, car battery and DC generator are the sources of direct current.
Question 18 :
Choose the incorrect statement from the following regarding magnetic lines of field
Question 19 :
Give an example of a metal which is a good conductor of heat.
Question 20 :
An element reacts with conductivity of metals oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be
Question 21 :
Give an example of a metal which is a poor conductor of heat.
Question 22 :
An electric iron consumes energy at a rate of 840 W when heating is at the maximum rate and the voltage is 220 V. What is the current when heating is at maximum rate?
Question 24 :
An electric motor takes 5 A from a 220 V line. What is the power of the motor?
Question 25 :
Name two elements that have two electrons in their outermost shells.
Question 27 :
Use Mendeleev's periodic table to predict the formulae for the oxides of the elements 'K'.
Question 28 :
How is ethene prepared from ethanol? Give the reaction involved in it.
Question 30 :
A compound X is formed by the reaction of a carboxylic acid $C_2H_4O_2$ and an alcohol in presence of a few drops of $H_2SO_4$. The alcohol on oxidation with alkaline $KMnO_4$ followed by acidification gives the same carboxylic acid as used in this reaction. Give the name and structure of carboxylic acid.
Question 31 :
State True or False: When HCl (g) is passed through water then it forms hydronium ion in the solution due to the combination of hydrogen ion with water molecule.
Question 32 :
Fill in the blank: Copper sulphate (_______) is formed using ______(base) and $H_2SO_4$(acid)
Question 33 :
What will be the action of the Lemon juice on litmus paper?
Question 34 :
A solar water heater cannot be used to get a hot water on:
Question 37 :
What is the balanced chemical equations when hydrogen gas combines with nitrogen to form ammonia?
Question 38 :
A solution of a substance ‘X’ is used for whitewashing. Name the substance ‘X’ and write its formula.
Question 40 :
Whether development of placenta is the function of testes at puberty?
Question 41 :
Why does bread mould grow profusely on a moist slice of bread rather than on a dry slice of bread?
Question 42 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61cc185078c526e972caea1f.PNG' />
In the above figure, which part mention the function Entry of the sperms.
Question 43 :
Refractive index of diamond with respect to glass is 1.6 and absolute refractive index of glass is 1.5. Find out the absolute refractive index of diamond.
Question 44 :
What type of image will form by a concave mirror, when an object is placed between pole and focus of the mirror.
Question 45 :
What type of image will form by a convex lens, when an object is placed at infinity.
Question 46 :
The most important safety method used for protecting home appliances from short circuiting or overloading is
Question 47 :
The strength of magnetic field inside a long current carrying straight solenoid is
Question 48 :
State TRUE or FALSE. The field at the centre of a long circular coil carrying current will be parallel straight lines.
Question 51 :
Which part of the brain comes into action while picking up a pencil?
Question 53 :
In our country, there are attempts to increase the height of several existing dams like Tehri and Almati, dams across Narmada. Choose the correct statements among the following that are a consequence of raising the height of dams -
(i)Terrestrial flora and fauna of the area is destroyed completely
(ii) Dislocation of people and domestic animals living in the area
(iii) Valuable agricultural land may be permanently lost
(iv) It will generate permanent employment for people
Question 57 :
Which of the following limits the number of trophic levels in a food chain?
Question 60 :
An element X of group 15 exists as diatomic molecule and combines with hydrogen at 773 K in presence of the catalyst to form a compound, ammonia which has a characteristic pungent smell. What type of bond is formed in diatomic molecule of X?
Question 62 :
The three elements A, B and C with similar properties have atomic masses X, Y and Z respectively. The mass of Y is approximately equal to the average mass of X and Z. What is such an arrangement of elements called as?
Question 63 :
During extraction of metals, electrolytic refining is used to obtain pure metals. Suggest a suitable electrolyte for refining of silver metal by this process.
Question 64 :
An element A reacts with water to form a compound B which is used in white washing. The compound B on heating forms an oxide C which on treatment with water gives back B. Identify C
Question 66 :
A non-metal A which is the largest constituent of air, when heated with $H_2$ in 1 : 3 ratio in the presence of catalyst (Fe) gives a gas B. On heating with $O_2$ it gives an oxide C. If this oxide is passed into water in the presence of air it gives an acid D which acts as a strong oxidising agent. The products are identified to be A-$N_2$, B-$NH_3$, C-NO, D-$HNO_3$. Is the identification correct?
Question 68 :
The __________ reproductive system in human beings consists of ovaries, fallopian tubes, uterus and vagina.
Question 69 :
The rate of general body growth begins to slow down, reproductive tissues begin to mature. Is it TRUE or FALSE?
Question 71 :
You cannot see a rainbow on a sunny day when you look at the sky through a waterfall or through a water fountain, with the sun behind you. TRUE or FALSE?
Question 72 :
The human eye forms the image of an object at its
Question 73 :
Which of the following phenomena of light are involved in the formation of a rainbow?
Question 75 :
Is the pattern of the magnetic field of a solenoid is similar to the pattern of magnetic field around a bar magnet ?
Question 76 :
State whether the given statement is true or false. 'An electric generator works on the principle of electromagnetic induction.'
Question 77 :
A convex mirror used for rear-view on an automobile has a radius of curvature of 3.00 m. If a bus is located at 5.00 m from this mirror, find the position of image.
Question 78 :
What would be the nature of image formed by convex lens when the object is placed at $2F_{1}$ ?
Question 80 :
Hydrogen has been used as a rocket fuel. Would you consider it a cleaner fuel than CNG?
Question 84 :
Which of the following is the correct order of the atomic radii of the elements oxygen, fluorine and nitrogen?
Question 86 :
Agitation is necessary to get clean clothes because the soap micelles which entrap oily or greasy particles on the surface of dirty cloth have to be removed from its surface. When the wetted cloth in soap solution is agitated, the micelles containing oily or greasy dirt particles get removed from the surface of dirty cloth and go into the water and the dirty cloth gets cleaned. TRUE or FALSE?
Question 87 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61cc185678c526e972caea2f.png' />
What is the name of the compound given above?
Question 89 :
Complete and balance the following equation :
$3Fe+4H_2O\rightarrow 4H_2\ + ..... $
Question 92 :
In what ways can our consumption of coal and petroleum products be reduced?
Question 93 :
The three R's that will help us to conserve natural resources for long term use are ______ , _______ and _______ .
Question 94 :
How can you as an individual contribute or make a difference to the management of coal and petroleum?
Question 95 :
Which of the following is not a part of the female reproductive system in human beings?
Question 100 :
For parallel refracting surfaces, the emergent ray intersects the incident ray. State whether the statement is true or false.
Question 101 :
Give an example of a metal which can be easily cut with a knife.
Question 102 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b19c7e273b230584979aeb.JPG' />
Samples of four metals A, B, C and D were taken and added to the different solution one by one. The results obtained have been tabulated above. Use the given table to answer the following questions about metals A, B, C and D.
Arrange the metals in decreasing order of reactivity.
Question 104 :
A spherical mirror and a thin spherical lens have each a focal length of -15 cm. The mirror and lens are likely to be:
Question 105 :
A doctor has prescribed a corrective lens of power + 1.5 D. Is the prescribed lens diverging or converging?
Question 106 :
Which one of the following materials cannot be used to make a lens?
