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Thermal properties of matter:, 2.1) Modes of transformation of heat:, , ¢ Difference between heat and temperature, definition of calorie,, Absolute zero, units of temperature: °C, °F, °K, with their, conversion., , e Conduction, law of thermal conductivity, coefficient of thermal, conductivity, good conductors of heat & insulators with suitable, examples, applications of conduction. Convection, applications of, convection. Radiation, applications of radiation, , 2.2) Gas laws: Boyle's law, Charles's law, Gay lussac;s law (statement, and mathematical equation only)Perfect gas equation (PV=RT) (No, derivation), specific heat of a substance, SI unit, specific heat of gas at, constant volume (C,), specific heat of gas at constant pressure (C,), ratio, of specific heat, Mayer's relation between C, and C,, isothermal process,, adiabatic process, difference between isothermal process and adiabatic, process., , ‘Scanned with CamScanner
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3.1, , Objectives , After studying thls unit students will able to:, , , , Convert given temperature in different temperature scales, , Describe properties of good and bad conductors of heat, , Relate characteristics of gas laws, , Determine relation between specific heats of given material, , Distinguish between phenomena of reflection, refraction, total internal reflection for given medium, , Describe propagation of light through optical fiber J et \, , , , Identify applications of optical fiber, , liquids and gases, molecules possess translational, , Thermal Properties of Matter a, , Introduction . - Thermal energy is the heat energy. It is the internal, , Matter consists of four types namely solids; liquid, gas energy of atoms in random motion inside the object., , and plasma. Atoms and molecules in a body are | — Exchange of energy with surrounding takes place., continuously in some kind of motion., , In case solids, atoms and molecules possess vibrational, energy due to collision of atoms of solid. In case of, , Scanned with CamScanner
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FF Basic Sclence-(Physics) (MSBTE - I Scheme), , 3.1.1 Heat, [Q. Define Heat., , (MSBTE : W-12), , Lw-12 i, , Amount of energy absorbed or evalved is called heat, denoted by Q., , Heat : It is the form of energy which produces, sensation of hotness., , All the molecules of a body possess small amount of, kinetic energy. Heat energy possessed by the body is, mainly due to kinetic energy of molecules., , On the other hand, heat, engine converts thermal, energy into mechanical energy. Thermal energy of a, system is defined as the average translational kinetic, energy of its particles., , According to principle of conservation of energy,, energy can be converted from one form to another. In, winter season, when we rub our palms to get the, , * sensation of warmth mechanical energy (due to, , friction) is converted into heat energy., , Definition : Heat energy of system is defined as the, sum of energies of all molecules in the system., , Heat is an extensive property., .e.g. Heat requires to boil % litre of water and heat, required to boil 4 litre of water is different., , Heat is the energy transferred from a body at higher, temperature (hot body) to a body at lower, temperature (cold body)., , Consider a container containing hot water kept on a, substrate in a surrounding at room temperature. The, hot water in‘a container gets colder as its temperature, decreases and approaches room temperature. There is, , exchange of heat energy between water and the, , surroundings., Heat is defined as the energy that flows from one body, to another body as the result of a temperature, , difference between them., , Considering the definition of heat the following things, , can be understood:, (a) Characteristic feature of heat is that heat is, transferred between two objects only when, , temperature difference exists between them., , (b) Object does not possess heat; heat Is a form of, energy rather than a substance., SI unit of heat enerBy is Joule and MKS unit is Kcal,, , In practice CGS unit of heat energy is calorie., , 3-2, , .___ Heat and Optics, , 3.1.2 Temperature, , Definition, , Temperature is a measure of hotness or coldness of a, body., , As heat is cause temperature, is its effect temperature, is measured using thermometer. SI unit is °k (Kelvin), When heat is supplied to any body, its temperature, increases i.e, its average kinetic energy increases. Let, us understand amount of kinetic energy., , E.g. — temperature of liquid is 60°C,, , Here all the molecules of liquid are supplied with, different heat energy, so different molecules have, different kinetic energies due to their random motion., ie. they possess range of kinetic energies. The, measure of average kinetic energies gives temperature, of liquid., , Temperature of body is directly proportional to, amount of kinetic energy of molecules of body., , More the K.E. of molecules, more is the temperature, of body., , Temperature is intensive property., , e.g. Boiling point of 1 litre water and 500 litre water is, , same., Temperature is a measure of translational kinetic, energy of the system., , 3.1.3 Difference between Heat and, , , , , , , , , , , , , , , , , , , , Temperature, Sr. Heat Temperature, “No. :, , 1. | Heatisasensation of | Temperature is the, hotness of body. measure of hotness or, , coldness of body., , 2. Heat flows from Temperature determines, higher temperature to | direction of flow of heat., lower temperature., , 3. Heat is extensive | Temperature is Intensive, property property., , 4. | Heat Is the cause Temperature is effect, , 5. | Heatis sum of Temperature is the, energies of all measure of average, molecules of the body | kinetic energy of the, , . body., 6. Slunitis joule -J Sl unit is kelvin - K, , , , , , , , , , TechKnouledgé, , Pupiications, , Scanned with CamScanner
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WF Basic Science-(Physics) (MSBTE - [ Scheme) 3-3, 3.1.4 Calorie (MSBTE : W-12, W-13), Q. Define Calorie., , , , , , , , , , One calorie of heat is defined as the amount of heat, energy required to increase the temperature of one gram, , of water through 1°C. The relation between Joule and, calorie is,, , 1calorie = 4.186 J., , 3.1.5 kcal (MSBTE : W-14), Q. Define : Kcal. . [w:14|, , , , , , , , , , One kilocalorie of heat is defined as the amount of, heat energy required to increase the temperature of one, kilogram of water through 1°C., , 1kcal = 4186), , 3.1.6 Absolute Zero Temperature, ‘ (MSBTE ; S-13, W-13, W-14, S-17), Q. Define absolute zero temperature. BE, , Q@. State/ Define absolute zero. FREAATA G3, , Q. What is the value of temperature at which ideally the, pressure of the gas become zero ?, , , , , , , , , , , , Definition of Absolute Zero Temperature, , - — The temperature at which pressure and volume of gas, theoretically becomes zero is called “absolute zero, temperature”. , — If gas is cooled then its pressure and .volume, decreases. It is observed that at — 273°C pressure and, volume of a gas theoretically becomes zero., ie. -273°C is minimum possible temperature for all, , gases. i1e,— 273°C = 0°K = 0° Absolute., , , , 3.1.7 °C, °F and °K Scales of Temperature, (MSBTE : S-13,S-17,W-15), , , , @. Explain Kelvin scale of temperature., Q. Define Kelvin scale of temperature., , , , , , Q. State relation between “C, F° and K., , , , — Thermometer is a device that measures temperature, dependant properties of matter., , — Example : In a clinical thermometer, expansion of, , , , mercury is measured., , Heat and Optics, , nt can be defined using, , Temperature measureme, lecting two ‘fixed points’, , temperature scale by sel, corresponding to reproducible temperature., , In these scales, /, Lower fixed point is melting point of pure ice at normal, pressure, , Upper fixed point i, normal pressure :, , is boiling point of pure water at, , Celsius scale (°C) of temperature - In tail scale, Lower fixed point = 0°C, Upper fixed point = 100°C, The scale is divided into 100 equal parts and each part, , is called °C., , Fahrenheit scale (°F) of temperature : In this scale, ., , Lower fixed point = 32°F, , Upper fixed point = 212°F, The scale is divided into 180 equal parts., Kelvin scale of temperature : In this scale., , Lower fixed point = 273°K, , Upper fixed point = 373°K, The scale is divided into 100 equal parts., Relation between °C, °F,, , 5, c = > (F-32), , Or F = (Bc)+32, , Relation between °C, °F and °K,, F-32, , = Tg =K-273°, , Kelvin or absolute scale of temperature is used where, the temperature is measured relative to an arbitrarily, chosen fixed point called ‘triple point of water’., , This fixed point is state where pure water coexists as a, mixture of ice, liquid and vapour. This state occurs at —, 273°C. The scale of temperature which has — 273°C as, , its zero designed by Kelvin is called as Kelvin absolute, scale of temperature., , CK), K, , [t °C) + 273], , Temperature in Kelvin, , t, , Temperature in degree Celsius, , , , , , Ka, ‘, , , , i, , , , Scanned with CamScanner
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Basic Science (Physics) (MSBTE - 1 Scheme), , 3-4, , Heat and Optics, , , , , , , , yooc 86 2t2F = aa" Boiling, saan ~-~ pointof water, a 2, ft :, = & a, oO co w, s 2 =, S o 5, st gsi 8, Melting, a === point of pure ice, of? 32°F 273°K, Cscale “Fscale °K scale, Fig. 3.1.1, , 3.1.7.1 Absolute Scale of Temperature, , (MSBTE : S$-14, S-16), , , , , , Q. “Whatis absolute scale of temperature ?, , , , , , , , , , It is the scale’of temperature in which the lower fixed, , point is 273°K and upper fixed point is 373°K. Further the, , scale is divided into 100 equal parts, each part Is degree, , Kelvin or degree absolute., , 1., 2., 3., , ‘3.1.7.2 Advantages of Kelvin Temperature, , The temperature is always positive., Gas laws can be explained only using kelvin scale., , Velocity of sound in air is directly proportional to, , + square root of absolute temperature., , 3.2 Modes of Transmission of Heat, , (MSBTE : W-13, W-16), , There are three types of mode of Transmission of Heat :, , , , , , , Conduction, 2. Convection, Radiation, , , , , , , 3.2.1. Conduction, , (MSBTE : W-13, W-16, S-17), , , , , , State conduction of heat. Cee, Stale and explain three modes of transmission of heat., , , , , Explain conduction. Give one example of each., , , , , , , , , , , , Q. State and explain three modes of transmission of heat., , , , of each., , , , , , , , , , Conduction is the process of transfer of heat energy, from a part of body at higher temperature to a part of, body at a lower temperature without bodily, , movement of particles., Conduction takes place in solids., , Consider a metal rod AB in which equidistant poles are, , * drilled to insert thermometers. Thermometers Ty, T,, , T; and T, are inserted in it. Before heating all the, thermometer shows equal temperature., Tr pte gts :, , , , , , , , , , , , , , Fig. 3.2.1, , Now, end A of the rod is heated, layer perceives the, heat energy. First molecules in the layer P start, vibrating about their mean position and transfer the, amount of heat energy to layer Q., , At the same time small amount of heat energy is, radiated to the surrounding. Similarly, molecules in the, layer Q start vibrating about their mean positions and, , transfer heat energy to layer R and soon,, , , , , , Ww TethKnowledg, , Pupiications, , Scanned with CamScanner