Laws of Thermodynamics | PART 1| MCQ | 2021

 Law of Thermodynamics

1. A definite area or space where some thermodynamic process takes place is known as……

1. Thermodynamics system

2. Thermodynamic cycles

3. Thermodynamics process

4. Thermodynamics law

2. An open system is one in which….

1. Heat and work cross the boundary of the system,but the mass of the working substance does not

2. Mass of working substance crosses the boundary of the system but the heat & work do not

3. Cannot transfer either energy or mass to or from the surroundings

4. Is one in which mass within the system is not necessarily constant

3. An isolated system….

1. is a specified region where transfer of energy and/or mass take place

2. is a region of constant mass & only energy is allowed to cross the boundaries

3. cannot transfer either energy or mass to or from the surroundings

4. is one in which mass within the system is not necessarily constant

4. Which of the following is an intensive property of a thermodynamic system

1. Volume

2. Temperature

3. Mass

4. Energy

5. In an extensive property of a thermodynamic system

1. extensive heat is transferred

2. extensive work is done

3. extensive energy is utilized

4. None of the above

6. Which of the following is the extensive property of a thermodynamic system

1. Pressure

2. Volume

3. Temperature

4. Density

7. When two bodies are in equilibrium with the third body they are also in thermal equilibrium with each other. This is called …

1. zeroth scale of thermodynamics

2. first law of thermodynamics

3. second law of thermodynamics

4. Kelvin Planck's law

8. The temperature at which the volume of a gas becomes zero is called

1. absolute scale of temperature

2. absolute zero temperature

3. absolute temperature

4. none of the above

9. The value of one bar (in SI units) is equal 

1. 100 N/m²

2. 1000 N/m²

3. 1×10⁴ N/m²

4. 1×10⁵ N/m²

10. The absolute zero pressure will be

1. when molecular momentum of the system becomes zero

2. at sea level

3. at the temperature of -273 K

4. under vacuum conditions

11. Absolute zero temperature is taken as

1. -273°C

2. 273°C

3. 237°C

4. -373°C

12. Which of the following is correct?

1. absolute pressure= gauge pressure+ atmospheric pressure

2. Gauge pressure= absolute pressure + atmospheric pressure

3. Atmospheric pressure= absolute pressure+ gauge pressure

4. Absolute pressure= gauge pressure- atmospheric pressure

13. The unit of energy in SI units is

1. S Joule (J)

2. Joule metre (Jm)

3. Watt (W)

4. Joule/metre (J/m)

14. One watt is equal to

1. 1 Nm/s

2. S 1N/min

3. 10 N/s

4. 100 Nm/s

15. One joule (J) is equal to

1. 1 Nm

2. kNm

3. 10 Nm/s

4. 10 kNm/s

16. The amount of heat required to raise the temperature of 1 kg of liquid state water through 1°C is called

1. specific heat at constant pressure

2. specific heat at constant volume

3. kilo calorie

4. none of the above

17. The heating & expanding of a gas is called

1. thermodynamic system

2. thermodynamic cycle

3. thermodynamic process

4. thermodynamic law

18. A series of operations, which take place in a certain order & restore the initial condition is known as

1. reversible cycle

2. irreversible cycle

3. thermodynamic cycle

4. none of the above

19. The condition for the reversibility of a cycle is

1. the pressure & temperature of the working substance must not differ, appreciably, from those of

2. all the processes, taking place in the cycle of operation, must be extremely slow

3. there should be no loss of energy during the cycle of operation

4. All of the above

20. In an irreversible process, there is a

1. loss of heat

2. no loss of heat

3. gain of heat

4. no gain of heat

21. The main cause of the irreversibility is

1. mechanical & fluid friction

2. unrestricted expansion

3. heat transfer with a finite temperature difference

4. all of the above

22. According to kinetic theory of heat

1. temperature should rise during boiling

2. temperature should fall during freezing

3. at low temperature all bodies are in solid state

4. at absolute zero there is absolutely no vibration of molecules

23. A system comprising a single phase is called a 

1. a closed system

2. open system

3. isolated system

4. homogeneous system

24. A control volume refers to

1. a fixed region in space

2. a specified mass

3. an isolated system

4. a reversible process only

25. Internal energy of a perfect gas depends on

1. temperature, specific heats & pressure

2. temperature, specific heats & enthalpy

3. temperature, specific heats & entropy

4. temperature only

26. In reversible polytrophic process

1. true heat transfer occurs

2. the entropy remains constant

3. the enthalpy remains constant

4. the internal energy remains constant

27. An isentropic process is always

1. irreversible & adiabatic 

2. reversible & isothermal 

3. frictionless & irreversible 

4. reversible & adiabatic

28. A reversible process requires that

1. there be no heat transfer

2.  Newton’s law of viscosity be satisfied

3.  temperature of system & surroundings be equal

4.  there be no viscous or coulomb friction in the system

29.  The first law of thermodynamics for steady flow 

1. accounts for all energy entering & leaving a control volume

2.  is an energy balance for a specified mass of fluid 

3. is an expression of the conservation of linear momentum

4.  is primarily concerned with heat transfer

30. The characteristic equation of gases pV=mRT holds good for 

1. monatomic gases

2.  diatomic gas

3.  real gases

4.  ideal gases

31. A gas which obeys kinetic theory perfectly known as

1. monatomic gas 

2. diatomic gas 

3. Perfect gas 

4. real gas

32. Work done in a free expansion process is 

1. zero 

2. minimum 

3. maximum 

4. positive

33. Which of the following is not a property of the system

1. temperature 

2. pressure

3.  specific volume

4.  Heat

34. In the polytrophic process equation pvⁿ = constant, if n is infinitely large, the process is termed as

1. constant volume

2.  constant pressure 

3. constant temperature

4.  adiabatic 

35. The process or systems that do not involve heat are called

1. isothermal processes

2. equilibrium processes

3.  thermal processes

4.  Adiabatic processes

36. In isothermal process

1. temperature increase gradually 

2. volume remains constant 

3. pressure remains constant 

4. change in internal energy is zero

37. During throttling process

1. internal energy does not change

2.  pressure does not change

3.  entropy does not change

4.  enthalpy does not change 

38. When a gas is to be stored, the type of compression that would be ideal is

1. isothermal processes

2.  adiabatic

3.  polytrophic 

4. constant volume

39. If a process can be stopped at any stage & reversed so that the system & surroundings are exactly restored to their initial states, it is known as

1. adiabatic process 

2. isothermal process

3.  Reversible process

4.  frictionless process

40. The state of a substance whose evaporation from its liquid state is complete, is known as 

1. vapour 

2. perfect gas

3.  air 

4. Steam

41. In SI units, the value of the universal gas constant is

1. 0.8314 J/mole/k

2.  8.314 J/mole/K

3.  8314 J/mole/K

4.  831.4 J/mole/K 

42. When the gas is heated at constant pressure, the heat supplied

1. increase the internal energy of the gas 

2. increases the temperature of the gas

3.  does some external work during expansion 

4. both (b) & ( c) 

43. The gas constant ® is equal to the

1. sum of two specific heats 

2. difference of two specific heats

3.  product of two specific heats 

4. ratio of two specific heat

44. Second law of thermodynamics defines

1. Heat

2.  Work

3.  Enthalpy

4.  entropy  

45. For a reversible adiabatic process, the change in entropy is 

1. zero 

2. minimum 

3. maximum 

4. infinite

46. For any reversible process, the change in entropy of the system & surroundings is 

1. negative 

2. unity

3.  zero

4.  Positive

47. For any irreversible process the net entropy change of system and surrounding

1. Zero

2.  Positive

3.  Negative

4.  Infinite

48. The processes of a Carnot cycle are 

1. two adiabatic & two constant volume 

2. one constant volume & one constant pressure & two isentropies 

3. two adiabatic & two isothermals

4.  two isothermals & two isentropies

49. Isentropic flow is

1. irreversible adiabatic flow

2.  ideal fluid flow

3.  perfect gas flow

4.  reversible adiabatic flow

50. In a Carnot engine, when the working substance gives heat to the sink

1. the temperature of the sink increases

2. the temperature of the sink remains same

3. the temperature of the source decreases

4.  the temperature of the source increases

51. If the temperature of the source is increased, the efficiency of the Carnot engine

1. Decrease

2.  increase 

3. does not change

4.  will be equal to the efficiency of a practical engine

52. The efficiency of an ideal Carnot engine depends on

1. working substance

2.  on the temperature of the source only

3.  on the temperature of the sink only

4.  On the temperature of the sources and sinks

53. In a reversible cycle, the entropy of the system

1. increases 

2. decreases

3.  does not change 

4. first increases & then decreases

54. A frictionless heat engine can be 100% efficient only if its exhaust temperature is

1. equal to its input temperature

2.  less than its input temperature

3.  0°C

4.  0°K

55. Kelvin-Plank's law deals with

1. conservation of energy 

2. conservation of heat 

3. conservation of mass

4.  conversion of heat into work 

56. Which of the following statements is correct according to Clausius statement of second law of thermodynamics? 

1. it is impossible to transfer heat from a body at a lower temperature to a body at a higher temperature 

2. it is impossible to transfer heat from a body at a lower temperature to a body at a higher temperature, without the aid of an external source

3.  it is possible to transfer heat from a body at a lower temperature to a body at a higher temperature by using refrigeration cycle

4.  none of the above 

57. According to Kelvin-Planck's statement of second law of thermodynamics

1. it is impossible to construct an engine working on a cyclic process, whose sole purpose is to convert heat energy into work

2.  it is possible to construct an engine working on a cyclic process, whose sole purpose is to convert the heat energy into work

3.  it is impossible to construct a device which while working in a cyclic process produces no effect other than the transfer of heat from a colder body to a hotter body 

4. None of the  above

58. The property of a working substance which increases or decreases as the heat is supplied or removed in a reversible manner is known as

1. enthalpy 

2. internal

3.  energy entropy

4.  all of the above

59. The entropy may be expressed as a function 

1. pressure & temperature 

2. temperature & volume

3.  heat & work 

4. all of the above 

60. The change of entropy when heat is absorbed by the gas is 

1. Positive

2.  Negative

3.  positive or negative

4.  all of the above

61. Which of the following statements is correct?

1. the increase in entropy is obtained from a given quantity of heat at a low temperature

2.  the change in entropy may be regarded as a measure of the rate of the availability of heat for transformation into work 

3. the entropy represents the maximum amount of work obtainable per degree drop in temperature 

4. all of the above

62. The condition for the reversibility of a cycle is 

1. the pressure & temperature of the working substance must not differ, appreciably, from those of the surroundings at any stage in the process

2.  all the processes taking place in the cycle of operation must be extremely slow 

3. the working parts of the engine must be friction free

4. all of the above

63. In an irreversible process, there is a 

1. loss of heat

2.  no loss of work

3.  gain of heat 

4. no gain of heat 

64. The main cause of the irreversibility is 

1. mechanical & fluid friction

2.  unrestricted expansion

3.  heat transfer with a finite temperature difference 

4. all of the above 

65. The efficiency of the Carnot cycle may be increased by

1. increasing the highest temperature

2.  decreasing the highest temperature

3.  increasing the lowest temperature

4.  decreasing the lowest temperature

66. Which of the following is the correct statement? 

1. all the reversible engines have the same efficiency 

2. all the reversible & irreversible engines have the same efficiency 

3. irreversible engines have maximum efficiency

4.  all engines are designed as reversible in order to maintain maximum efficiency

67. The reversible engines are

1. least efficient 

2. most efficient 

3. having same efficiency as irreversible engines 

4. none of the above

68. Gases could have an infinite number of specific heats but only ……. Specific heats are defined

1. One

2.  two 

3. three 

4. four

69. Which one of the following statements is correct?

1. pressure is an extensive property

2.  Density is an intensive property

3.  density is an extensive property

4.  temperature is an extensive property

70. First law of thermodynamics deals with conservation of

1. mass 

2. movements

3.  energy

4.  Heat

71. The area under the T-s (temperature - entropy) curve of any thermodynamic process represents 

1. heat rejected only 

2. heat absorbed only

3. work done during the process

4. heat absorbed or reject

72. Second law of thermodynamics defines

1. Work

2.  Heat

3.  Entropy

4. internal energy

73. Which one of the following processes or systems does not involve heat 

1. steady processes

2.  isothermal processes

3.  adiabatic processes 

4. thermal processes 

74. For storing a gas which one of the following types of compression will be ideal

1. constant volume

2.  polytrophic 

3. Adiabatic

4.  isothermal 

75. A process which can be stopped at any stage & reversed so that the system & the surroundings are exactly restored to their thermodynamic process irreversible process reversible process isothermal process C initial states is known as 

1. thermodynamic process 

2. irreversible process

3.  reversible process 

4. isothermal process 

76. Thermodynamic equilibrium is completely defined by the specification of

1. generalized displacements

2.  internal energy 

3. Enthalpy

4.  all of the above

77. Which of the following is heterogeneous system? 

1. cooking gas in a cylinder 

2. atmospheric air

3.  a mixture of ice, water & steam

4.  a mixture of hydrogen & oxygen 

78. Which one of the following gases obeys kinetic theory perfectly?

1. perfect gas 

2. pure gas

3.  monoatomic gas 

4. diatomic gas

79. ………. Is not a property of the system

1. pressure 

2. temperature

3.  heat 

4. specific volume

80. In which of the following processes the external work done is not zero?

1. throttling 

2. free expansion 

3. constant volume process

4.  constant pressure process

81. The extension & compression of a helical spring is an example of

1. irreversible process 

2. reversible process

3.  isothermal process 

4. adiabatic process 

82. In all irreversible processes, the entropy of the system

1. remains unaltered

2.  reduces to zero

3.  increases 

4. none of the above 

83. Due to which of the following reasons food can be cooked quicker in a pressure cooker?

1. it is made of a metal

2.  steam remains within the cooker

3.  high pressure steam has a high temperature

4.  none of the above

84. Which of the following is a reversible process? 

1. throttling 

2. combustion

3. free expansion

4.  extension & compression of spring

85. Leaking of air from a punctured tube is an example of

1. isothermal expansion

2.  adiabatic expansion

3.  throttling 

4. constant pressure expansion

86. Temperature of a gas is produced due to which of the following?

1. attraction of molecules 

2. repulsion of molecules 

3. kinetic energy of molecule

4.  all of the above

87. The same volume of all gases would represent their 

1. specific gravity 

2. densities 

3. specific weights

4.  molecular weights

88. To convert volumetric analysis to gravimetric analysis, the relative volume of each constituent of the flue gases is

1. divided by its specific weight

2.  multiplied by its density 

3. multiplied by its molecular weight 

4. divided by its molecular weight 

89. First law of thermodynamics gives relationship between which of the following?

1. heat & internal energy

2.  heat &work

3. Heat work and properties of the system

4. Various thermodynamic processes

90.  The temperature in a process in which work is done by expanding a gas under adiabatic condition will 

1. Decrease

2.  increase 

3. first decrease & then increase 

4. remain unaltered 

91. On which of the following laws measurement of temperature is based?

1. joule's law

2.  zeroth law of thermodynamics

3.  first law of thermodynamics

4.  second law of thermodynamics

92. The perpetual motion of the first kind is represented by which of the following? 

1. a machine that continuously creates its own energy

2.  an engine with 100 percent efficiency 

3. a fully reversible engine

4.  none of the above

93. Which of the following statements regarding a perpetual motion machine is correct?

1. it is an in efficient machine

2.  it is non-thermodynamic machine 

3. it is thermodynamic machine

4.  it is hypothetic machine whose operation would violate the laws of thermodynamics

94. Which of the following statement regarding a property of system, is correct?

1. it is path function

2.  it is a point function 

3. it is always of intensive type

4.  none of the above

95. ……….. Is an intensive property 

1. specific volume

2.  total volume

3.  total mass 

4. total energy of a system

96. Which of the following processes undergoes energy loss due to friction? 

1. reversible process

2.  irreversible process

3.  isentropic process 

4. adiabatic process 

100. A system is said to be in thermodynamic equilibrium if it is in

1. chemical equilibrium 

2. thermal equilibrium

3. mechanical equilibrium

4. all of the above  

101. Which of the following statements is correct?

1. irreversible engines have maximum efficiency

2. all the reversible engines have same efficiency

3.  all the reversible engines working between the same temperature limit have the same efficiency

4.  all the engines have same efficiency

102. Kelvin Planck's law deals with conservation of

1. Work

2.  Heat

3.  work into heat

4.  heat into work

103. A thermodynamic process will be reversible when the temperature difference between hot body & working                        substance is

1. minimum 

2. maximum

3.  infinity

4.  Zero

104. The basis for measuring thermodynamic property of temperature is given by …….Law of thermodynamics

1. Zeroth

2.  first 

3. Second

4.  third 

105.  As differentials, heat & work would be described mathematically as

1. Exact

2.  Inexact

3.  point function

4.  discontinuity 

106.  Which of the following is an open thermodynamic system?

1. pressure cooker

2.  manual ice cream freezer 

3. centrifugal pump

4.  none of the above

106. ……… is a non-quasistatic process 

1. free expansion of gas 

2. expansion of gas in a cylinder under constant pressure 

3. rapid leakage of air from a bicycle tyre

4. gradual compression of gas inside a piston-cylinder arrangement

          107) heat engine receives heat at the rate of 1500 kJ/min. & gives an output of 8.2 kW. Its thermal efficiency is equal to

1. 20.50%

2.  30.20% 

3. 32.80%

4.  44.60% 

108. An inventor claims that a new heat cycle will develop 0.4 kW for a heat addition of  3 2.5 kJ/mm. The temperature of heat source is 1990 K & that of sink is 850K. Is his claim true?

1. TRUE 

2. FALSE 

3. either of the above 

4. unpredictable

109. Consider the following statements: The definition of 1. temperature is due to zeroth law of thermodynamics 2.entropy is due to first law of thermodynamics 3.internal energy is due to second law of thermodynamics 4 reversibility is due to Kelvin-Planck's statement of these statements

1. .1,2 & 3 are correct

2.  1,3 & 4 are correct

3.  1 alone is correct

4.  2 alone is correct 

110. A heat engine is supplied with 250 kJ/s of heat at a constant fixed temperature of 227°C. The heat rejected at 27°C. The cycle is reversible, if the amount of heat rejected is

1. 273 kJ/s 

2. 200 kJ/s

3.  180 kJ/s

4.  150 kJ/s 

111. A Carnot engine receiving heat at 400K has an efficiency of 25%. The C.O.P. of a Carnot refrigerator working between the same temperature limits is

1. 1

2.  2

3.  3 

4. 4 

112.  If a heat engine gives an output of 3 kW when the input is 10,000 J/s, then the thermal efficiency of the engine will be

1. 20%

2.  30% 

3. 70%

4.  76.70% 

113.  The fundamental unit of enthalpy is

1. MLT ˉ²

2.  ML²Tˉ¹

3. ML²T ˉ² 

4. ML³T ˉ² 

114.  In a cyclic heat engine operating between a source temperature of 600°C & a sink temperature of 20°C, the least rate of heat rejection per kW net output of the engine is 

1. 0.460 kW 

2. 0.505 kW 

3. 0.588 kW 

4. 0.650 kW

115. In a reversible cycle the source temperature is 227°C & the sink temperature is 27°C. The maximum available work for a heat input of 100 kJ will be 

1. 100 kJ

2.  60 kJ 

3. 40 kJ

4.  88 kJ

116. A heat engine using lake water at 12° C as source & the surrounding atmosphere at 2°C as sink executes 1080 cycles per min. If the amount of heat drawn per cycle is 57J, then the output of the engine will be 

1. 66 W 

2. 56 W

3.  46 W 

4. 36 W

117. One reversible heat engine operates between 1600 K & T₂ K & another reversible heat engine operates between T₂ K & 400 K. If both the engines have the temperature T₂ must be equal to

1. 100 kJ

2.  1200 K

3.  1400 K

4.  800 K

118. An engine receives 15152 J/s of heat & produces 5 KW of power. The efficiency of the engine is 

1. 25% 

2. 27.50

3. 30% 

4. 33%

119.  Choose the correct statement

1. pressure, temp and entropy are extensive property

2. pressure ,temp and entropy are intensive property

3. pressure ,volume ,temp and entropy are extensive property

4. volume and entropy are extensive property

120. The second law of thermodynamics defines

1. heat 

2. enthalpy

3.  internal energy

4.  entropy

121. The first law of thermodynamics defines 

1. Entropy

2.  internal energy

3.  work 

4. Heat

122. Which law of thermodynamics defines entropy 

1. First

2.  second 

3. third 

4. zeroth 

123. A process becomes irreversible due to

1. work performed by the system work

2.  performed upon the system

3.  heat supplied to the system 

4. friction in the system

124. Which of the following processes is essentially irreversible

1. Isothermal

2.  adiabatic

3.  Isentropic

4.  throttling 

125. A thermodynamic cycle operates between 400 K. & 290 K. 500 MJ/s of heat is added to the working substance. The power generated is

1. 290 MW

2.  290 MJ 

3. 137.5 MJ 

4. 137.5 MW

126. A reversible engine performing as engine has efficiency of 62.5%. If it is reversed to work as refrigerator its COP will be 

1. 60% 

2. 62.50% 

3. 65% 

4. 37.50% 

127. A reversible engine performing as refrigerator has COP=33%. If the same machine operates as engine, its efficiency will be

1. 67% 

2. 33%

3.  75% 

4. 37.50%

128. The amount of heat absorbed by a system at lower temperature is 

1. coefficient Of performance 

2. efficiency

3.  work supplied 

4. refrigerating effect