Chapter # 11 Heat

PHYSICS

CHAPTER # 11 Heat and Thermodynamics

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The degree of hotness or coldness of an object is expressed in terms of: a) Heat capacity b) Heat c) Temperature d) Heat energy Which of the following properties of matter is used in the construction of a thermometer: a) Expansion of matter on heating b) Change of color with temperature c) Increase of resistance with rise of temperature d) All of these Mercury is used in mercury-in-glass thermometer as a thermometric substance because: a) It does not wet the capillary tube walls b) It is opaque c) Its expansion is uniform over a wide range of temperature d) All of above Two fixed points used for the temperature scales are: a) The temperature of freezing and boiling mercury b) The temperature of melting ice and boiling water c) The temperature of water at 0oC and 100oC d) None of these In liquid-in-glass thermometer, the thermometric property used is: a) Thermal expansion b) Color change on heating c) Resistance change on heating d) None of these The lower and upper fixed points on Celsius (centigrade) scale are taken to be: a) 0o and 212o b) 32o and 273o o o c) 0 and 100 d) None of these A Celsius (centigrade) degree is greater than a Fahrenheit degree by: a) 5/9 b) 9/5 c) 18/5 d) 9/10 The Centigrade and Fahrenheit scales have the same reading at: a) 40o b) 140o o c) -140 d) -40o The relationship between Celsius and Fahrenheit scales temperature is: a) Fo = 9/5 Co - 32 b) Fo = 9/5 Co + 32 o o c) C = 9/5 F + 32 d) None of these The temperature of a normal human body is 98.6 Fo. This temperature corresponds to: a) 20 Co b) 30 Co c) 37 Co d) 66.6 Co o The temperature of normal human body is 37 C . On Kelvin scale, it is equal to: a) 373 Ko b) 273 Ko o c) 310 K d) 236 Ko One degree of centigrade scale is equal to: a) 1o of Fahrenheit b) 1.8o of Fahrenheit o c) 32 of Fahrenheit d) 3o of Fahrenheit o 10 C corresponds to: a) 273o K b) 283o K o c) 263 K d) 100o K The temperature of absolute zero corresponds to: a) -273 Co b) 273 Co o c) 0 C d) 20 Co What temperature on Fahrenheit scale corresponds to absolute zero? a) 212o F b) 32o F o c) -32 F d) -460o F One Calorie is equal to: a) 41.8 J b) 4.18 J c) 18.4 J d) 4.35 J SI unit of heat energy is: a) Calorie b) B.T.U. c) Joule d) Kilo-Calorie Absolute zero is considered to be the temperature at which: a) All gases become liquids b) All liquids become gases c) Water freezes d) Molecular motion in gases would cease The Kelvin and Fahrenheit scales show the same reading at: a) 57.42o b) 5.74o o c) 574.25 d) -574.25o Which of the following does not have the same units: a) Mechanical energy b) Kinetic energy c) Heat energy d) Power Melting point of ice and boiling point of water in Fahrenheit scale are taken as: a) 0o and 100o b) 32o and 272o o o c) 100 and 373 d) 32o and 212o Bahadur li Qureshi- 1 -

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CHAPTER # 11 Heat and Thermodynamics

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Which of the following represents the total energy of the molecules of the substance: a) Translational K.E. and rotational K.E. b) Rotational K.E. and Vibrational K.E. c) Vibrational K.E., Translational K.E. and Potential energy d) Translational K.E, Vibrational K.E, rotational K.E. and Potential energy The average K.E of all the molecules in a substance is a measure of: a) Heat energy b) Temperature c) Boiling point d) Specific heat The total sum of all the energies of the molecules in a substance is called: a) Heat energy b) Kinetic energy c) Temperature d) Potential energy Keeping temperature of gas constant, the Boyl’s law can be expressed as: a) V  P b) V  1/P c) V  1/T d) P  V When pressure of gas remains constant, the Charle’s law can be expressed as: a) V  T b) V  1/T  c) V P d) None of these At constant pressure, the graph between volume (V) and temperature (T) is: a) A curve b) A parabola c) A hyperbola d) A straight line Real gases strictly obey gas laws at: a) Low pressure & low temperature b) High pressure & low temperature c) Low pressure & high temperature d) High pressure & high temperature “Volume of a gas is directly proportional to its temperature (absolute) while keeping pressure constant”, this is called: a) Boyl’s law b) Charle’s law c) Ideal gas law d) None of these “Volume of a gas is inversely proportional to its pressure while keeping temperature constant”, this is called: a) Boyl’s law b) Charle’s law c) Ideal gas law d) None of these For a gas obeying Boyl’s law if the pressure is doubled, the volume becomes: a) Three fold b) Double c) One-half d) Remains the same The K.E. of the molecules of an ideal gas at absolute zero will be: a) Zero b) Infinite c) Very high d) Below zero At absolute zero of temperature, the molecules have: a) Rotational K.E b) Translational K.E c) Maximum energy d) Zero energy In an ideal gas, the molecules have: a) Kinetic energy only b) Potential energy only c) Both Kinetic and Potential energies d) None of these The molecules of the gas exert pressure on the walls of the container due to: a) Their velocity b) Their continuous collision c) Their free motion d) Their energy The relation between Boltzman constant K, gas constant R and Avogadro’s number NA is: a) K = NA/R b) K= RNA c) K = R/NA d) K = R - NA The pressure exerted by the gas molecules is: a) Inversely proportional to average translational K.E. of molecules b) Directly proportional to average translational K.E. of molecules c) Inversely proportional to number of molecules per unit volume of the gas d) None of the above The absolute temperature of an ideal gas is: a) Directly proportional to average translational K.E. of the molecules b) Inversely proportional to average translational K.E. of the molecules c) Directly proportional to the universal gas constant d) None of the above Heat is form of energy associated with: a) Molecular mass b) Molecular motion c) Molecular weight d) None of these The pressure of gas, at constant temperature, varies with density as: 2 a) P  1/  b) P  1/  c) P  

2 d) P  

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CHAPTER # 11 Heat and Thermodynamics

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When the pressure is increased, the boiling point of liquid: a) Increases b) Decreases c) Remains unchanged d) All of these The pressure is measured in units of: a) Pascal b) Atmosphere c) N/m2 d) All of these The change in length per unit length per Kelvin rise temperature is called: a) Coefficient of superficial expansion b) Coefficient of volume expansion c) Coefficient of linear expansion d) None of these The linear thermal expansion is related to: a) Liquids only b) Gases only c) Both liquids and gases d) Solids only When most substances are heated: a) They expand b) Their volume increases c) Their density decreases d) All of these The change in volume per unit volume per Kelvin rise in temperature is called: a) Coefficient of linear expansion b) Coefficient of thermal conductivity c) Temperature coefficient d) Coefficient of volume expansion The relation between coefficient of linear expansion (  ) and coefficient of volume expansion (  ) is: a)  =  /2 b)  =  c)  = 2  d)  = 3 

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An inflated tyre suddenly bursts, due to which the temperature of air: a) Decreases b) Increases c) Remains the same d) None of these 51. SI unit of coefficient of linear expansion (or volume expansion) is: a) C° b) K° c) C°-1 d) K°-1 52. The energy of molecular motion appears in the form of: a) Temperature b) Friction c) Potential energy d) Heat 53. Ice becomes slippery when man walks on it because: a) There is no friction b) Increase of pressure causes it to melt c) Ice surface is smooth d) It is very cold 54. A thermometer made by bonding together two dissimilar metals having different thermal expansivity is called: a) A liquid thermometer b) A resistance thermometer c) A maximum & minimum thermometer d) A bimetallic thermometer 55. Bimetallic thermometer is used: a) In automobiles for the automatic choke b) In thermostats for refrigerator c) As an oven thermometer d) All of these 56. The amount of heat needed to raise the temperature of body through 1 Ko is called: a) Heat capacity b) Specific heat c) Calorie d) Heat of fusion 57. The amount of heat energy required to raise temperature of 1 Kg of substance through 1 K is called: a) Heat capacity b) Specific heat c) Molar heat capacity d) Heat of vaporization 58. The relation between heat capacity and specific heat is: a) Heat capacity = specific heat/mss b) Heat capacity = specific heat  mass c) Heat capacity = specific heat – mass d) None of these 59. Heat gained (or lost) by a body of mass m and specific heat c when its temperature is raised through t , is gained by: a) Q = m T / c b) Q = m c/ T c) Q = m c T d) Q = m c T / m

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The amount of heat needed to raise the temperature of 1 gram of water through 1 Co is called: a) Joule b) Calorie c) Kilo Calorie d) B.T.U. The amount of heat needed to raise the temperature of 1 kg of water through 1Ko is called: a) Calorie b) Kilo Calorie c) Joule d) None of these The heat capacity per unit mass of a body is called: a) Heat of fusion b) Latent heat c) Specific heat d) Calorie Bahadur li Qureshi- 3 -

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CHAPTER # 11 Heat and Thermodynamics

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Heat needed to melt 1kg of ice at its melting point without change of temperature is called: a) Heat capacity b) Heat of vaporization c) Specific heat d) Latent heat of fusion of ice 64. The quantity of heat needed to raise the temperature of 1 mole of a substance through 1Ko is called: a) Specific heat b) Molar heat capacity c) Heat capacity d) Joule 65. For a monoatomic gas, if Cp and Cv represent specific heats at constant pressure and at constant volume respectively, then: a) Cp < Cv b) Cp = Cv c) Cp > Cv d) None of these 66. SI units of specific heat are: a) J Kg/K b) J/Kg K c) Cal/Kg K d) K Cal/Kg C 67. The product of specific heat of a calorimeter and its mass is called: a) Latent heat b) Coefficient of heat exchange c) Water equivalent d) None of these 68. Which one of the expressions can be used to calculate molar specific heat Cm of a substance: a) Cm = mass  molecular weight b) Cm = specific heat  molecular weight c) Cm = heat capacity  molecular weight d) Cm = mass  specific heat 69. The difference between Cp and Cv is equal to: a) One Calorie b) Boltzman constant c) Universal gas constant d) Zero 70. The ratio Cp/Cv for a diatomic gas like air is: a) 1.40 b) 1.30 c) 1.50 d) 1.67 71. The ratio Cp/Cv for a monoatomic gas like air is: a) 1.30 b) 1.40 c) 1.52 d) 1.67 72. Suppose heat is added to a mixture of ice and water at 0 C° until all the ice is melted. During the melting process the temperature of the mixture: a) Increases b) Decreases c) Remains the same d) Decreases first and then increases 73. A system in which there is no transfer of mass and energy across the boundary is called: a) A closed system b) An isolated system c) An open system d) None of these 74. The rate of cooling of a body depends on: a) The nature of the body b) The size of the body c) The difference in temperature between the body and its surroundings d) None of the above 75. The first law of thermodynamics is merely a statement of: a) Law of conservation of momentum b) Law of conservation of mass c) Law of conservation of energy d) Charle’s law 76. Which of the following relations express first law of thermodynamics: a) Q = U + W b) Q = U - W c) W = Q + U d) U = Q + W

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In SI units, Joule is the unit of: a) Heat energy b) Change in internal energy c) Work done d) All of these The process in which the temperature of the system remains constant is called: a) Adiabatic process b) Isothermal process c) Isochoric process d) Isobaric process In which of the following processes no heat enters or leaves the system: a) Isothermal process b) Isobaric process c) Isochoric process d) Adiabatic process The process in which the Pressure of the system remains constant is called: a) Isobaric process b) Adiabatic process c) Isochoric process d) Isothermal process In an adiabatic process a) Work done is positive b) Work is done at the cost of internal energy c) No work is done d) Neither of these On a hot day or in hot climates white clothes are worn because they are good: a) Emitters b) Absorbers c) Reflectors d) Radiators The equation PV  = constant holds good in: a) Adiabatic process b) Isothermal process c) Isobaric process d) Isochoric process Bahadur li Qureshi- 4 -

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In an isothermal process, the internal energy of the system: a) Increases b) Decreases c) Remains constant d) None of these Which one of the following is the example of irreversible process: a) Peltier effect b) Work done against friction c) Melting of ice d) Isothermal process Which one of the following is the example of reversible process: a) Heat produced by current b) Melting of ice c) Work done against friction d) None of these If the temperature of the source increase, the efficiency of the carnot engine: a) Increases b) Decreases c) Remains constant d) None of thse If the temperature of the sink is decreased, the efficiency of a carnot engine: a) Decreases b) Increases c) Remains constant d) Becomes zero Which property of a system remains constant during adiabatic change: a) Pressure b) Temperature c) Internal energy d) Entropy The efficiency of a carnot engine depends on: a) The temperature of the source only b) The temperature of the sink only c) Both temperature of source and sink d) The working substance Entropy is the measure of: a) Order of the system b) Disorder of the system c) Internal energy of the system d) Kinetic energy of the system Net change in entropy of a system in a carnot’s cycle is: a) Negative b) Positive c) Entropy remains the same d) None of these When the temperature of source and sink of a heat engine becomes equal, the entropy change will be a) Maximum b) Minimum c) Zero d) Negative No entropy change is associated with: a) Isobaric process b) Adiabatic process c) Isothermal process d) Isochoric process Entropy is called as “Time Arrow” because the entropy of the universe: a) Always increases b) Always decreases c) Remains constant d) Sometimes increases & sometimes decreases Work done by an expanding gas under adiabatic condition results in: a) Temperature increases b) Temperature decreases c) No change in temperature d) Temperature increases first then decreases The natural direction of heat flow between two reservoirs depend upon: a) Their heat contents b) Their pressures c) Their temperature d) None of these A perfect gas is that which: a) Obeys Charle’s law only b) Obeys Boyle’s law only c) Does not obey gas laws d) Strictly obeys all gas laws The pressure of a gas is defined as: a) Force per unit length b) Force per unit area c) Force per unit volume d) Force per unit density The energy possessed by the molecules in a substance consists of: a) Vibrational energy b) Rotational energy c) Translational energy d) All of these Alcohol is used as a thermometric liquid because of its: a) Cohesive properties b) High heat capacity c) Low freezing point d) Ability to conduct Work done by an expanding gas under adiabatic condition results in: a) Temperature decrease b) Temperature increase c) No change in temperature d) Temperature increase first then decrease Solids possess definite shape due to large: a) Force of adhesion b) Force of cohesion c) Force of gravitation d) Force of friction Given the basic units of Joule as Kg m2s-2, what are the basic units of specific heat capacity? a) m s-1 k-1 b) m s-2 k-1 -1 2 -1 c) Kg m k d) m2 s-2 k-1

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The temperature of 1 Kg of hydrogen gas is the same as that of 1 kg of helium gas if: a) The gases have the same internal energy b) The gases radiate energy at the same rate c) The gas molecules have same average translational kinetic energy d) The gas molecules occupy equal volumes The molar heat capacity of an ideal gas at constant pressure is greater than that at constant volume because: a) Work has to be done against intermolecular forces as the gas expands b) Work has to be done against external pressure as the gas expands c) The molecules gain rotational kinetic energy as the gas expands d) None of these When a monatomic ideal gas undergoes an isothermal change: a) The number of degrees of freedom of the molecules changes b) The temperature changes c) There is no change of internal energy d) No external work is done The internal energy of a fixed mass of an ideal gas depends on: a) Pressure b) Temperature c) Volume d) None of these

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