1000+ TOP Thermodynamics MCQs and Answers Quiz Exam

Thermodynamics Multiple Choice Questions

1. Which of the following variables controls the physical properties of a perfect gas
A. pressure
B. temperature
C. volume
D. all of the above
E. atomic mass.
Answer: D

2. Which of the following laws is applicable for the behavior of a perfect gas
A. Boyle’s law
B. Charles’law
C. Gay-Lussac law
D. all of the above
E. Joule’s law.
Answer: D

3. The unit of temperature in S.I. units is
A. Centigrade
B. Celsius
C. Fahrenheit
D. Kelvin
E. Rankine.
Answer: D

4. The unit of mass in S.I. units is
A. kilogram
B. gram
C. tonne
D. quintal
E. newton.
Answer: A

5. The unit of time in S.I. units is
A. second
B. minute
C. hour
D. day
E. year.
Answer: A

6. The unit of length in S.I. units is
A. meter
B. centimeter
C. kilometer
D. millimeter.
Answer: A

7. The unit of energy in S.I. units is
A. watt
B. joule
C. joule/s
D. joule/m
E. joule m.
Answer: B

8. According to Gay-Lussac law for a perfect gas, the absolute pressure of given mass varies directly as
A. temperature
B. absolute
C. absolute temperature, if volume is kept constant
D. volume, if temperature is kept constant
E. remains constant,if volume and temperature are kept constant.
Answer: C

9. An ideal gas as compared to a real gas at very high pressure occupies
A. more volume
B. less volume
C. same volume
D. unpredictable behaviour
E. no such correlation.
Answer: A

10. General gas equation is
A. PV=nRT
B. PV=mRT
D. PV = C
C. PV=KiRT
E. Cp-Cv = Wj
Answer: B

11. According to Dalton’s law, the total pres sure of the mixture of gases is equal to
A. greater of the partial pressures of all
B. average of the partial pressures of all
C. sum of the partial pressures of all
D. sum of the partial pressures of all divided by average molecular weight
E. atmospheric pressure.
Answer: C

12. Which of the following can be regarded as gas so that gas laws could be applicable, within the commonly encountered temperature limits.
A. 02, N2, steam, C02
B. Oz, N2, water vapour
C. S02, NH3, C02, moisture
D. 02, N2, H2, air
E. steam vapours, H2, C02.
Answer: D

13. The unit of pressure in S.I. units is
A. kg/cm2
B. mm of water column
C. pascal
D. dynes per square cm
E. bars
Answer: C

14. A closed system is one in which
A. mass does not cross boundaries of the system, though energy may do so
B. mass crosses the boundary but not the energy
C. neither mass nor energy crosses the boundaries of the system
D. both energy and mass cross the boundaries of the system
E. thermodynamic reactions take place.
Answer: A

15. Temperature of a gas is produced due to
A. its heating value
B. kinetic energy of molecules
C. repulsion of molecules
D. attraction of molecules
E. surface tension of molecules.
Answer: B

16. According to kinetic theory of gases, the absolute zero temperature is attained when
A. volume of the gas is zero
B. pressure of the gas is zero
C. kinetic energy of the molecules is zero
D. specific heat of gas is zero
E. mass is zero.
Answer: C

17. Kinetic theory of gases assumes that the collisions between the molecules are
A. perfectly elastic
B. perfectly inelastic
C. partly elastic
D. partly inelastic
E. partly elastic and partly inelastic.
Answer: A

18. The pressure’of a gas in terms of its mean kinetic energy per unit volume E is equal to
A. E/3
B. E/2
C. 3E/4
D.2E/3
E. 5E/4.
Answer: D

19. Kinetic energy of the molecules in terms of absolute temperature (T) is proportional to
A. T
B. j
C. J2
D. Vr
E. 1/Vr.
Answer: A

20. Superheated vapour behaves
A. exactly as gas
B. as steam
C. as ordinary vapour
D. approximately as a gas
E. as average of gas and vapour.
Answer: D

21. Absolute zero pressure will occur
A. at sea level
B. at the center of the earth
C. when molecular momentum of the system becomes zero
D. under vacuum conditions
E. at a temperature of – 273 °K
Answer: C

22. No liquid can exist as liquid at
A. – 273 °K
B. vacuum
C. zero pressure
D. centre of earth
E. in space.
Answer: C

23. The unit of power in S.I. units is
A. newton
B. pascal
C. erg
D. watt
E. joule.
Answer: D

24. The condition of perfect vacuum, i.e., absolute zero pressure can be attained at
A. a temperature of – 273.16°C
B. a temperature of 0°C
C. a temperature of 273 °K
D. a negative pressure and 0°C temperature
E. can’t be attained.
Answer: A

25. Intensive property of a system is one whose value
A. depends on the mass of the system, like volume
B. does not depend on the mass of the system, like temperature, pressure, etc.
C. is not dependent on the path followed but on the state
D. is dependent on the path followed and not on the state
E. remains constant.
Answer: B

26. Specific heat of air at constant pressure is equal to
A. 0.17
B. 0.21
C. 0.24
D. 1.0
E. 1.41
Answer: C

27. Characteristic gas constant of a gas is equal to
A. C/Cv
B. Cv/Cp
C. Cp – Cv
D. Cp + Cv
E. Cp x Cv
Answer: C

28. The behaviour of gases can be fully determined by
A. 1 law
B. 2 laws
C. 3 laws
D. 4 laws
Answer: D

29. The ratio of two specific heats of air is equal to
A. 0.17
B. 0.24
C. 0.1
D. 1.41
E. 2.71.
Answer: D

30. Boyle’s law i.e. pV = constant is applicable to gases under
A. all ranges of pressures
B. only small range of pressures
C. high range of pressures
D. steady change of pressures
E. atmospheric conditions.
Answer: B

31. Which law states that the internal energy of a gas is a function of temperature
A. Charles’ law
B. Joule’s law
C. Regnault’s law
D. Boyle’s law
E. there is no such law.
Answer: B

32. The same volume of all gases would represent their
A. densities
B. specific weights
C. molecular weights
D. gas characteristic constants
E. specific gravities.
Answer: C

33. Which law states that the specific heat of a gas remains constant at all temperatures and pressures
A. Charles’ Law
B. Joule’s Law
C. Regnault’s Law
D. Boyle’s Law
E. there is no such law.
Answer: C

34. An open system is one in which
A. mass does not cross boundaries of the system, though energy may do so
B. neither mass nor energy crosses the boundaries of the system
C. both energy and mass cross the boundaries of the system
D. mass crosses the boundary but not the energy
E. thermodynamic reactions do not occur.
Answer: C

35. According to which law, all perfect gases change in volume by l/273th of their original volume at 0°C for every 1°C change in temperature when pressure remains constant
A. Joule’s law
B. Boyle’s law
C. Regnault’s law
D. Gay-Lussac law
E. Charles’ law.
Answer: E

36. Gases have
A. only one value of specific heat
B. two values of specific heat
C. three values of specific heat
D. no value of specific heat
E. under some conditions one value and sometimes two values of specific heat.
Answer: B

37. According to Avogadro’s Hypothesis
A. the molecular weights of all the perfect gases occupy the same volume under same conditions of pressure and temperature
B. the sum of partial pressure of mixture of two gases is sum of the two
C. product of the gas constant and the molecular weight of an ideal gas is constant
D. gases have two values of specific heat
E. all systems can be regarded as closed systems.
Answer: A

38. Extensive property of a system is one whose value
A. depends on the mass of the system like volume
B. does not depend on the mass of the system, like temperature, pressure, etc.
C. is not dependent on the path followed but on the state
D. is dependent on the path followed and not on the state
E. is always constant.
Answer: A

39. Work done in a free expansion process is
A. + ve
B. -ve
C. zero
D. maximum
E. minimum.
Answer: C

40. The statement that molecular weights of all gases occupy the same volume is known as
A. Avogadro’s hypothesis
B. Dalton’s law
C. Gas law
D. Law of thermodynamics
E. Joule’s law.
Answer: A

41. To convert volumetric analysis to gravimetric analysis, the relative volume of each constituent of the flue gases is
A. divided by its molecular weight
B. multiplied by its molecular weight
C. multiplied by its density
D. multiplied by its specific weight
E. divided by its specific weight.
Answer: B

42. If a gas is heated against a pressure, keeping the volume constant, then work done will be equal to
A. + v
B. – ve
C. zero
D. pressure x volume
E. any where between zero and infinity.
Answer: C

43. An isolated system is one in which
A. mass does not cross boundaries of the system, though energy may do so
B. neither mass nor energy crosses the boundaries of the system
C. both energy and mass cross the boundaries of the system
D. mass crosses the boundary but not the energy
E. thermodynamic reactions do not occur.
Answer: B

44. Properties of substances like pressure, temperature and density, in thermodynamic coordinates are
A. path functions
B. point functions
C. cyclic functions
D. real functions
E. thermodynamic functions.
Answer: B

45. Which of the following quantities is not the property of the system
A. pressure
B. temperature
C. specific volume
D. heat
E. density.
Answer: D

46. According to Avogadro’s law, for a given pressure and temperature, each molecule of a gas
A. occupies volume proportional to its molecular weight
B. occupies volume proportional to its specific weight
C. occupies volume inversely proportional to its molecular weight
D. occupies volume inversely proportional to its specific weight
E. occupies same volume.
Answer: E

47. Mixture of ice and water form a
A. closed system
B. open system
C. isolated system
D. heterogeneous system
E. thermodynamic system.
Answer: D

48. Which of the following is the property of a system
A. pressure and temperature
B. internal energy
C. volume and density
D. enthalpy and entropy
E. all of the above.
Answer: E

49. On weight basis, air contains following parts of oxygen
A. 21
B. 23
C. 25
D. 73
E. 79.
Answer: B

50. Which of the following is not the intensive property
A. pressure
B. temperature
C. density
D. heat
E. specific volume.
Answer: D

51. Which of the following items is not a path function
A. heat
B. work
C. kinetic energy
D. vdp
E. thermal conductivity.
Answer: E

52. Work done in an adiabatic process between a given pair of end states depends on
A. the end states only
B. particular adiabatic process
C. the value of index n
D. the value of heattransferred
E. mass of the system.
Answer: A

53. Heat and work are
A. point functions
B. system properties
C. path functions
D. intensive properties
E. extensive properties.
Answer: C

54. Which of the following parameters is constant for a mole for most of the gases at a given temperature and pressure
A. enthalpy
B. volume
C. mass
D. entropy
E. specific volume.
Answer: B

55. The value of n = 1 in the polytropic process indicates it to be
A. reversible process
B. isothermal process
C. adiabatic process
D. irreversible process
E. free expansion process.
Answer: B

56. Solids and liquids have
A. one value of specific heat (ft) two values of specific heat
C. three values of specific heat
D. no value of specific heat
E. one value under some conditions and two values under other conditions.
Answer: A

57. A perfect gas at 27°C is heated at constant pressure till its volume is double. The final temperature is
A. 54°C
B. 327°C
C. 108°C
D. 654°C
E. 600°C
Answer: B

58. Curve A in Fig. 1.1 compared to curves B and C shows the following type of expansion
A. pV”=C
B. isothermal
C. adiabatic
D. free expansion
E. throttling.
Answer: B

59. If value of n is infinitely large in a polytropic process pV” = C, then the process is known as constant
A. volume
B. pressure
C. temperature
D. enthalpy
E. entropy.
Answer: A

60. The index of compression n tends to reach ratio of specific heats y when
A. flow is uniform and steady
B. process is isentropic
C. process is isothermal
D. process is isentropic and specific heat does not change with temperature
E. process is isentropic and specific heat changes with temperature.
Answer: D

61. Change in enthalpy of a system is the heat supplied at
A. constant pressure
B. constant temperature
C. constant volume
D. constant entropy
E. N.T.P. condition.
Answer: A

62. The term N.T.P. stands for
A. nominal temperature and pressure
B. natural temperature and pressure
C. normal temperature and pressure
D. normal thermodynamic practice
E. normal thermodynamic pressure.
Answer: C

63. A heat exchange process in which the product of pressure and volume remains constant is known as
A. heat exchange process
B. throttling process
C. isentropic process
D. adiabatic process
E. hyperbolic process.
Answer: E

64. In an isothermal process, the internal energy of gas molecules
A. increases
B. decreases
C. remains constant
D. may increase/decrease depending on the properties of gas
E. shows unpredictable behaviour.
Answer: C

65. Zeroth law of thermodynamics
A. deals with conversion of mass and energy
B. deals with reversibility and irreversibility of process
C. states that if two systems are both in equilibrium with a third system, they are in thermal equilibrium with each other
D. deals with heat engines
E. does not exist.
Answer: C

66. If a certain amount of dry ice is mixed with same amount of water at 80°C, the final temperature of mixture will be
A. 80°C
B. 0°C
C. 40°C
D. 20°C
E. 60°C.
Answer: B

67. The basis for measuring thermodynamic property of temperature is given by
A. zeroth law of thermodynamics
B. first law of thermodynamics
C. second law of thermodynamics
D. third law of thermodynamics
E. Avogadro’s hypothesis.
Answer: A

68. One watt is equal to
A. 1 Nm/s
B. 1 N/mt
C. 1 Nm/hr
D. 1 kNm/hr
E. 1 kNm/mt.
Answer: A

69. Work done is zero for the following process
A. constant volume
B. free expansion
C. throttling
D. all Of the above
E. none of the above.
Answer: D

70. For which of the following substances, the gas laws can be used with minimum error
A. dry steam
B. wet steam
C. saturated steam
D. superheated steam
E. steam at atmospheric pressure.
Answer: D

71. In a non-flow reversible process for which p = (- 3V+ 15) x 105N/m2,V changes from 1 m to 2 m3. The work done will be about
A. 100 xlOO5 joules
B. lxlO5 joules
C. 10 xlO5 joules
D. 10 xlO5 kilo joules
E. 10xl04kiojoules.
Answer: C

72. The value of the product of molecular weight and the gas characteristic constant for all the gases in M.K.S. unit is
A. 29.27 kgfm/mol°K
B. 8314kgfm/mol°K
C. 848kgfm/mol°K
D. 427kgfm/mol°K
E. 735 kgfm/mol°K.
Answer: C

73. On volume basis, air contains following parts of oxygen
A. 21
B. 23
C. 25
D. 77
E. 79.
Answer: A

74. Universal gas constant is defined as equal to product of the molecular weight of the gas and
A. specific heat at constant pressure
B. specific heat at constant volume
C. ratio of two specific heats
D. gas constant
E. unity.
Answer: D

75. The value of the product of molecular weight and the gas characteristic constant for all the gases in S.I. units is
A. 29.27 J/kmol°K
B. 83.14J/kmol°K
C. 848J/kmol°K
D. All J/kmol °K
E. 735 J/kmol °K.
Answer: B

76. For which of the following substances, the internal energy and enthalpy are the functions of temperature only
A. any gas
B. saturated steam
C. water
D. perfect gas
E. superheated steam.
Answer: D

77. In a free expansion process
A. work done is zero
B. heat transfer is zero
C. both A. and B. above
D. work done is zero but heat increases
E. work done is zero but heat decreases.
Answer: C

78. If a gas vapour is allowed to expand through a very minute aperture, then such a process is known as
A. free expansion
B. hyperbolic expansion
C. adiabatic expansion
D. parabolic expansion
E. throttling.
Answer: E

79. The specific heat of air increases with increase in
A. temperature
B. pressure
C. both pressure and temperature
D. variation of its constituents
E. air flow
Answer: A

80. If a fluid expands suddenly into vacuum through an orifice of large dimension, then such a process is called
A. free expansion
B. hyperbolic expansion
C. adiabatic expansion
D. parabolic expansion
E. throttling.
Answer: A

81. Which of the following processes are thermodynamically reversible
A. throttling
B. free expansion
C. constant volume and constant pressure
D. hyperbolic and pV = C
E. isothermal and adiabatic.
Answer: E

82. Which of the following processes is irreversible process
A. isothermal
B. adiabatic
C. throttling
D. all of the above
E. none of the above.
Answer: C

83. In order that a cycle be reversible, following must be satisfied
A. free expansion or friction resisted expansion/compression process should not be encountered
B. when heat is being absorbed, temperature of hot source and working sub¬stance should be same
C. when beat is being rejected, temperature of cold source and working sub-stance should be same
D. all of the above
E. none of the above.
Answer: D

84. For a thermodynamic process to be reversible, the temperature difference between hot body and working substance should be
A. zero
B. minimum
D. maximum
D. infinity
E. there is no such criterion.
Answer: A

85. Minimum work in compressor is possible when the value of adiabatic index n is equal to
A. 0.75
B. 1
C. 1.27
D. 1.35
E. 2.
Answer: B

86. Molecular volume of any perfect gas at 600 x 103 N/m2 and 27°C will be
A. 4.17m3/kgmol
B. 400 m3/kg mol
C. 0.15 m3/kg mol
D. 41.7 m3/kg mol
E. 417m3/kgmol.
Answer: A

87. A gas is compressed in a cylinder by a movable piston to a volume one-half its original volume. During the process 300 kJ heat left the gas and internal energy remained same. The work done on gas in Nm will be
A. 300 Nm
B. 300,000 Nm
C. 30 Nm
D. 3000 Nm
E. 30,000 Nm.
Answer: B

88. The more effective way of increasing efficiency of Carnot engine is to
A. increase higher temperature
B. decrease higher temperature
C. increase lower temperature
D. decrease lower temperature
E. keep lower temperature constant.
Answer: D

89. Entropy change depends on
A. heat transfer
B. mass transfer
C. change of temperature
D. thermodynamic state
E. change of pressure and volume.
Answer: A

90. For reversible adiabatic process, change in entropy is
A. maximum
B. minimum
C. zero
D. unpredictable
E. negative.
Answer: C

91. Isochoric process is one in which
A. free expansion takes place
B. very little mechanical work is done by the system
C. no mechanical work is done by the system
D. all parameters remain constant
E. mass and energy transfer do not take place.
Answer: C

92. According to first law of thermodynamics
A. work done by a system is equal to heat transferred by the system
B. total internal energy of a system during a process remains constant
C. internal energy, enthalpy and entropy during a process remain constant
D. total energy of a system remains constant
E. entropy of a system remains constant.
Answer: D

93. Energy can neither be created nor destroyed but can be converted from one form to other is inferred from
A. zeroth low of thermodynamic
B. first law of thermodynamics
C. second law to thermodynamics
D. basic law of thermodynamics
E. claussius statement.
Answer: B

94. First law of thermodynamics furnishes the relationship between
A. heat and work
B. heat, work and properties of the system
C. various properties of the system
D. various thermodynamic processes
E. heat and internal energy.
Answer: B

95. Change in enthalpy in a closed system is equal to heat transferred if the reversible process takes place at constant
A. pressure
B. temperature
C. volume
D. internal energy
E. entropy.
Answer: A

96. In an isothermal process, the internal energy
A. increases
B. decreases
C. remains constant
D. first increases and then decreases
E. first decreases and then increases.
Answer: C

97. Change in internal energy in a closed system is equal to heat transferred if the reversible process takes place at constant
A. pressure
B. temperature
C. volume
D. internal energy
E. entropy.
Answer: C

98. According to first law of thermodynamics
A. mass and energy are mutually convertible
B. Carnot engine is most efficient
C. heat and work are mutually convertible
D. mass and light are mutually convertible
E. heat flows from hot substance to cold substance.
Answer: C

99. Total heat of a substance is also known as
A. internal energy
B. entropy
C. thermal capacity
D. enthalpy
E. thermal conductance.
Answer: D

100. First law of thermodynamics
A. enables to determine change in internal energy of the system
B. does not help to predict whether the system will or not undergo a change
C. does not enable to determine change in entropy
D. provides relationship between heat, work and internal energy
E. all of the above.
Answer: E

Applied Thermodynamics Objective Questions with Answers Pdf  Download

101. Addition of heat at constant pressure to a gas results in
A. raising its temperature
B. raising its pressure
C. raising its volume
D. raising its temperature and doing external work
E. doing external work.
Answer: D

102. Carnot cycle has maximum efficiency for
A. reversible engine
B. irreversible engine
C. new engine
D. petrol engine
E. diesel engine.
Answer: A

103. Measurement of temperature is based on
A. thermodynamic properties
B. zeroth law of thermodynamics
C. first law of thermodynamics
D. second law of thermodynamics
E. joule’s law.
Answer: B

104. Carnot cycle efficiency depends upon
A. properties of the medium/substance used
B. condition of engine
C. working condition
D. temperature range of operation
E. effectiveness of insulating material around the engine.
Answer: D

105. Carnot cycle efficiency is maximum when
A. initial temperature is 0°K
B. final temperature is 0°K
C. difference between initial and final temperature is 0°K
D. final temperature is 0°C
E. initial temperature is minimum possible.
Answer: B

106. An engine operates between temperatures of 900°Kandr2 and another engine between T2 and 400°K For both to do equal work, value of T2 will be
A. 650°K
B. 600°K
C. 625°K
D. 700°K
E. 750°K.
Answer: A

107. If heat be exchanged in a reversible manner, which of the following property of the working substance will change accordingly
A. temperature
B. enthalpy
C. internal energy
D. entropy
E. all of the above.
Answer: D

108. If a system after undergoing a series of processes, returns to the initial state then
A. process is thermodynamically in equilibrium
B. process is executed in closed system cycle
C. its entropy will change due to irreversibility
D. sum of heat and work transfer will be zero
E. no work will be done by the system.
Answer: D

109. Which of the following represents the perpetual motion of the first kind
A. engine with 100% thermal efficiency
B. a fully reversible engine
C. transfer of heat energy from low temperature source to high temperature source
D. a machine that continuously creates its own energy
E. production of energy by temperature differential in sea water at different levels.
Ans:

110. An actual engine is to be designed having same efficiency as the Carnot cycle. Such a proposition is
A. feasible
B. impossible
C. possible
D. possible, but with lot of sophistications
E. desirable.
Answer: D

112. A manufacturer claims to have a heat engine capable of developing 20 h.p. by receiving heat input of 400 kcal/mt and working between the temperature limits of 227° C and 27° C. His claim is
A. justified
B. not possible
C. may be possible with lot of sophistications
D. cost will be very high
E. theroretically possible.
Answer: B

113. In a Carnot cycle, heat is transferred at
A. constant pressure
B. constant volume
C. constant temperature
D. constant enthaply
E. any one of the above.
Answer: C

114. A diathermic wall is one which
A. prevents thermal interaction
B. permits thermal interaction
C. encourages thermal interaction
D. discourages thermal interaction
E. does not exist.
Answer: B

115. An adiabatic wall is one which
A. prevents thermal interaction
B. permits thermal interaction
C. encourages thermal interaction
D. discourages thermal interaction
E. dos not exist.
Answer: A

116. The door of a running refrigerator inside a room was left open. Which of the following statements is correct?
A. The room will be cooled to the temperature inside the refrigerator.
B. The room will be cooled very slightly.
C. The room will be gradually warmed up.
D. The temperature of the air in room will remain unaffected.
E. any one of above is possible depending on the capacity.
Answer: C

117. Compressed air coming out from a punctured football
A. becomes hotter
B. becomes cooler1
C. remains at the same temperature
D. may become hotter or cooler depend-ing upon the humidity of the surround¬ing air
E. attains atmospheric temperature.
Answer: B

118. Water contained in a beaker can be made to boil by passing steam through it
A. at atmospheric pressure
B. at a pressure below the firuosphejric pressure
C. at a pressure greater than atmospheric pressure
D. any pressure
E. not possible.
Answer: C

119. During throttling process
A. heat exchange does not take place
B. no work is done by expanding steam
C. there is no change of internal energy of steam
D. all of the above
E. entropy decreases.
Answer: D

120. The energy of molecular motion appears as
A. heat
B. potential energy
C. surface tension
D. friction
E. increase in pressure.
Answer: A

121. A sudden fall in the barometer reading is a sign of approaching
A. fine weather
B. rains
C. storm
D. cold wave
E. hot wave.
Answer: C

122. The unit’of universal gas constant is
A. watts/°K
B. dynes/°C
C. ergscm/°K
D.erg/°K
E. none of the above.
Answer: D

123. Calorie is a measure of
A. specific heat
B. quantity of heat
C. thermal capacity
D.entropy
E. work.
Answer: B

124. I kgf/cm2 is equal to
A. 760 mm Hg
B. zero mm Hg
C. 735.6 mm Hg
D. 1 mm Hg
E. lOOmmHg.
Answer: C

125. Barometric pressure is equal to
A. 760 mm Hg
B. zero mm Hg
C. 735.6 mm Hg
D. 1 mm Hg
E. 100mm Hg.
Answer: A

126. One barometric pressure or 1 atmospheric pressure is equal to
A. 1 kgf/cnr2
B. 1.033 kgf/cm2
C. 0 kgf/cm2
D. 1.0197 kgf/cm2
E. 100 kgf/cm2.
Answer: B

127. The first law of thermodynamics is the law of
A. conservation of mass
B. conservation of energy
C. conservation of momentum
D. conservation of heat
E. conservation of temperature.
Answer: B

128. A perpetual motion machine is
A. a thermodynamic machine
B. a non-thermodynamic machine
C. a hypothetical machine
D. a hypothetical machine whose opera-tion would violate the laws of thermodynamics
E. an inefficient machine.
Answer: D

129. Kelvin Planck’s law deals with
A. conservation of heat
B. conservation of work
C. conversion of heat into work
D. conversion fo work into heat
E. conservation of mass.
Answer: C

130. According to Clausis statement of second law of thermodynamics
A. heat can’t be transferred from low temperature source to high temperature source
B. heat can be transferred for low temperature to high temperature source by using refrigeration cycle.
C. heat can be transferred from low temperature to high temperature source if COP of process is more than unity
D. heat can’t be transferred from low temperature to high temperature source without the aid of external energy
E. all of the above.
Answer: D

131. Thermal power plant works on
A. Carnot cycle
B. Joule cycle
D. Rankine cycle
D. Otto cycle
E. Brayton cycle.
Answer: C

132. Which of the following is an irreversible cycle
A. carnot
B. Stirling
C. ericsson
D. all of the above
E. none of the above.
Answer: E

133. Otto cycle consists of following four processes
A. two isothermals and two isentropics
B. two isentropics and two constant volumes
C. two isentropics, one constant volume and one constant pressure
D. two isentropics and two constant pres-sures
E. none of the above.
Answer: B

134. The efficiency of a Carnot engine depends on
A. working substance
B. design of engine
C. size of engine
D. type of fuel fired
E. temperatures of source and sink.
Answer: E

135. For same compression ratio and for same heat added
A. Otto cycle is more efficient than Diesel cycle
B. Diesel cycle is more efficient than Otto cycle
C. efficiency depends on other factors
D. both Otto and Diesel cycles are equally efficient
E. none of the above.
Answer: A

136. The efficiency of Carnot cycle is maximum for
A. gas engine
B. well lubricated engine
C. petrol engine
D. steam engine
E. reversible engine.
Answer: E

137. Carnot cycle is
A. a reversible cycle (ft) an irreversible cycle
C. a semi-reversible cycle
D. a quasi static cycle
E. an adiabatic irreversible cycle.
Answer: A

138. Diesel cycle consists of following four processes
A. two isothermals and two isentropics
B. two isentropics, and two constant volumes.
C. two isentropics, one constant volume and one constant pressure
D. two isentropics and two constant pressures
E. none of the above.
Answer: C

139. If both Stirling and Carnot cycles operate within the same temperature limits, then efficiency of Stirling cycle as compared to Carnot cycle
A. more
B. less
C. equal
D. depends on other factors
E. none of the above.
Answer: C

140. Stirling and Ericsson cycles are
A. reversible cycles
B. irreversible cycles
C. quasi-static cycles
D. semi-reversible cycles
E. adiabatic irreversible cycles.
Answer: A

141. A cycle consisting of two adiabatics and two constant pressure processes is known as
A. Otto cycle
B. Ericsson cycle
C. Joule cycle
D. Stirling cycle
E. Atkinson cycle.
Answer: C

142. Reversed joule cycle is called
A. Carnot cycle
B. Rankine cycle
C. Brayton cycle
D. Bell Coleman cycle
E. Dual cycle.
Answer: C

143. Brayton cycle consists’ of following four processes
A. two isothermals and two isentropics
B. two isentropics and two constant volumes
C. two isentropics, one constant volume and one constant pressure
D. two isentropics and two constant pres-sures
E. none of the above.
Answer: D

144. Which of the following cycles is not a reversible cycle
A. Carnot
B. Ericsson
C. Stirling
D. Joule
E. none of the above.
Answer: E

145. The cycle in which heat is supplied at constant volume and rejected at constant pressure is known as
A. Dual combustion cycle
B. Diesel cycle
C. Atkinson cycle
D. Rankine cycle
E. Stirling cycle.
Answer: C

146. The efficiency of Diesei cycle with decrease in cut off
A. increases
B. decreases
C. remains unaffected
D. first increases and then decreases
E. first decreases and then increases.
Answer: A

147. Which of the following cycles has maximum efficiency
A. Rankine
B. Stirling
C. Carnot
D. Brayton
E. Joule.
Answer: C

148. The ideal efficiency of a Brayton cycle without regeneration with increase ni pressure ratio will
A. increase
B. decrease
C. remain unchanged
D. increase/decrease depending on application
E. unpredictable.
Answer: A

149. The ideal efficiency of a Brayton cycle with regeneration, with increase in pressure ratio will
A. increase
B. decrease
C. remain unchanged
D. increase/decrease depending on ap-plication
E. unpredictable. ”
Answer: B

150. The following cycle is used for air craft refrigeration
A. Brayton cycle
B. Joule cycle
C. Carnot cycle
D. Bell-Coleman cycle
E. Reversed-Brayton cycle.
Answer: E

151. Gas turbine cycle consists of
A. two isothermals and two isentropics
B. two isentropics and two constant volumes
C. two isentropics, one constant volume and one constant pressure
D. two isentropics and two constant pressures
E. none of the above.
Answer: D

152. The thermodynamic difference between a Rankine cycle working with saturated steam and the Carnot cycle is that
A. carnot cycle can’t work with saturated steam
B. heat is supplied to water at temperature below the maximum temperature of the cycle
C. a rankine cycle receives heat at two places
D. rankine cycle is hypothetical
E. none of the above.
Answer: B

153. An ideal gas as compared to a real gas at very high pressure occupies

A. More volume

B. Less volume

C. Same volume

D. Unpredictable behavior

Answer: A

154. In open cycle gas turbine plants

A. Direct combustion systems is used

B. A condenser is used

C. The indirect heat exchanger and cooler is avoided

D. All of the above

Answer: D

155. One Joule (J) is equal to

A. 1 kN-m

B. 1 N-m

C. 10 kN-m/s

D. 10 N-m/s

Answer: B

156. General gas equation is

A. PV=nRT

B. PV=mRT

C. PV = C

D. PV=KiRT

Answer: B

157. Kinetic theory of gases assumes that the collisions between the molecules are

A. Perfectly elastic

B. Perfectly inelastic

C. Partly elastic

D. Partly inelastic

Answer: A

158. The pressure of a gas in terms of its mean kinetic energy per unit volume ‘E’ is equal to

A. E/3

B. E/2

C. 3E/4

D. 2E/3

Answer: D

159. Kinetic energy of the molecules in terms of absolute temperature (T) is proportional to

A. T

B. J

C. J²

D. Vr

Answer: A

160. The efficiency of Joule cycle is

A. Less than Carnot cycle

B. Equal to Carnot cycle

C. Greater than Carnot cycle

D. None of these

Answer: A

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

A. Perfect gas

B. Vapour

C. Steam

D. Air

Answer: A

162. Which law states that the internal energy of a gas is a function of temperature?

A. Charles’ law

B. Joule’s law

C. Boyle’s law

D. There is no such law

Answer: B

163. The same volume of all gases would represent their

A. Densities

B. Specific weights

C. Molecular weights

D. Gas characteristic constants

Answer: C

164. Which law states that the specific heat of a gas remains constant at all temperatures and pressures?

A. Charles’ Law

B. Joule’s Law

C. Regnault’s Law

D. Boyle’s Law

Answer: C

165. An open system is one in which

A. Mass does not cross boundaries of the system, though energy may do so

B. Neither mass nor energy crosses the boundaries of the system

C. Both energy and mass cross the boundaries of the system

D. Mass crosses the boundary but not the energy

Answer: C

166. The hyperbolic process is governed by

A. Avogadro’s law

B. Boyle’s law

C. Charles’ law

D. Gay-Lussac law

Answer: B

167. Which of the following quantities is not the property of the system?

A. Pressure

B. Temperature

C. Specific volume

D. Heat

Answer: D

168. The sum of internal energy (U) and the product of pressure and volume (p.v) is known as

A. Work done

B. Entropy

C. Power

D. Enthalpy

Answer: D

169. Which of the following gas has a minimum molecular mass?

A. Nitrogen

B. Hydrogen

C. Methane

D. Oxygen

Answer: B

170. According to Avogadro’s law, for a given pressure and temperature, each molecule of a gas

A. Occupies same volume

B. Occupies volume proportional to its specific weight

C. Occupies volume inversely proportional to its molecular weight

D. Occupies volume inversely proportional to its specific weight

Answer: A

171. Mixture of ice and water form a

A. Closed system

B. Open system

C. Isolated system

D. Heterogeneous system

Answer: D

172. The entropy of water at 0°C is assumed to be

A. 0

B. -1

C. 1

D. 2

Answer: A

173. The index of compression ‘n’ tends to reach ratio of specific heats ‘y’ when

A. Flow is uniform and steady

B. Process is isentropic

C. Process is isothermal

D. Process is isentropic and specific heat does not change with temperature

Answer: D

174. Change in enthalpy of a system is the heat supplied at

A. Constant pressure

B. Constant temperature

C. Constant volume

D. Constant entropy

Answer: A

175. The term N.T.P. stands for

A. Nominal temperature and pressure

B. Natural temperature and pressure

C. Normal temperature and pressure

D. Normal thermodynamic practice

Answer: C

176. A heat exchange process in which the product of pressure and volume remains constant is known as

A. Heat exchange process

B. Throttling process

C. Isentropic process

D. Hyperbolic process

Answer: D

177. Universal gas constant is defined as equal to product of the molecular weight of the gas and

A. Specific heat at constant pressure

B. Specific heat at constant volume

C. Ratio of two specific heats

D. Gas constant

Answer: D

178. A cycle consisting of one constant pressure, one constant volume and two isentropic processes is known as

A. Otto cycle

B. Stirling cycle

C. Carnot cycle

D. Diesel cycle

Answer: D

179. During which of the following process does heat rejection takes place in Carnot cycle?

A. Isothermal expansion

B. Isentropic expansion

C. Isothermal compression

D. Isentropic compression

Answer: C

180. The value of the product of molecular weight and the gas characteristic constant for all the gases in S.I. units is

A. 29.27 J/kmol °K

B. 83.14 J/kmol °K

C. 848 J/kmol °K

D. 735 J/kmol °K

Answer: B

181. For which of the following substances, the internal energy and enthalpy are the functions of temperature only

A. Any gas

B. Saturated steam

C. Water

D. Perfect gas

Answer: D

182. The more effective way of increasing efficiency of Carnot engine is to

A. Increase higher temperature

B. Decrease higher temperature

C. Increase lower temperature

D. Decrease lower temperature

Answer: D

183. Which of the following has the minimum atomic mass?

A. Sulphur

B. Nitrogen

C. Oxygen

D. Carbon

Answer: D

184. The processes occurring in open system which permit the transfer of mass to and from the system, are known as

A. Flow processes

B. Non-flow processes

C. Adiabatic processes

D. None of these

Answer: A

185. Entropy change depends on

A. Heat transfer

B. Mass transfer

C. Change of temperature

D. Thermodynamic state

Answer: A

186. For reversible adiabatic process, change in entropy is

A. Maximum

B. Minimum

C. Zero

D. Negative

Answer: C

187. Carnot cycle has maximum efficiency for

A. Reversible engine

B. Irreversible engine

C. Petrol engine

D. Diesel engine

Answer: A

188. The efficiency of Diesel cycle increases with

A. Increase in cut-off

B. Constant cut-off

C. Decrease in cut-off

D. None of these

Answer: C

189. The amount of heat required to raise the temperature of the unit mass of gas through one degree at constant volume, is called

A. Kilo Joule

B. Specific heat at constant volume

C. Specific heat at constant pressure

D. None of these

Answer: B

190. Measurement of temperature is based on

A. Thermodynamic properties

B. Zeroth law of thermodynamics

C. First law of thermodynamics

D. Second law of thermodynamics

Answer: B

191. Carnot cycle efficiency depends upon

A. Properties of the medium/substance used

B. Condition of engine

C. Working condition

D. Temperature range of operation

Answer: D

192. Compressed air coming out from a punctured football

A. Becomes hotter

B. Becomes cooler

C. Remains at the same temperature

D. May become hotter or cooler depending upon the humidity of the surrounding air

Answer: B

193. Water contained in a beaker can be made to boil by passing steam through it

A. At atmospheric pressure

B. At a pressure greater than atmospheric pressure

C. Any pressure

D. Not possible

Answer: B

194. During throttling process

A. Heat exchange does not take place

B. No work is done by expanding steam

C. There is no change of internal energy of steam

D. All of the above

Answer: D

195. The energy of molecular motion appears as

A. Heat

B. Potential energy

C. Surface tension

D. Friction

Answer: A

196. The compression ratio for Diesel engines is

A. 15 to 20

B. 5 to 8

C. 3 to 6

D. 20 to 30

Answer: A

197. The efficiency of Diesel cycle approaches to Otto cycle efficiency when

A. Cut-off is decreased

B. Cut-off is constant

C. Cut-off is increased

D. Cut-off is zero

Answer: B

198. According to Clausius’ statement of second law of thermodynamics

A. Heat can’t be transferred from low temperature source to high temperature source

B. Heat can be transferred for low temperature to high temperature source by using refrigeration cycle

C. Heat can be transferred from low temperature to high temperature source if COP of process is more than unity

D. Heat can’t be transferred from low temperature to high temperature source without the aid of external energy

Answer: D

199. Thermal power plant works on

A. Carnot cycle

B. Joule cycle

C. Rankine cycle

D. Otto cycle

Answer: C

200. The atomic mass of oxygen is

A. 14

B. 16

C. 18

D. 121

Answer: B

201. An adiabatic process is one in which

A. The temperature of the gas changes

B. No heat enters or leaves the gas

C. The change in internal energy is equal to the mechanical work done

D. All of the above

Answer: D

202. Which of the following is an irreversible cycle?

A. Carnot

B. Stirling

C. Ericsson

D. None of the above

Answer: D

203. Otto cycle consists of following four processes

A. Two isothermal and two isentropic

B. Two isentropic and two constant volumes

C. Two isentropic, one constant volume and one constant pressure

D. Two isentropic and two constant pressures

Answer: B

204. The efficiency of a Carnot engine depends on

A. Working substance

B. Design of engine

C. Size of engine

D. Temperatures of source and sink

Answer: D

205. For same compression ratio and for same heat added

A. Otto cycle is more efficient than Diesel cycle

B. Diesel cycle is more efficient than Otto cycle

C. Efficiency depends on other factors

D. Both Otto and Diesel cycles are equally efficient

Answer: A

206. Which of the following statement is incorrect?

A. The liquid fuels have higher calorific value than solid fuels

B. The solid fuels have higher calorific value than liquid fuels

C. A good fuel should have low ignition point

D. The liquid fuels consist of hydrocarbons

Answer: C

207. The compression ratio for petrol engines is

A. 3 to 6

B. 5 to 8

C. 10 to 20

D. 15 to 30

Answer: B

208. The efficiency of Carnot cycle is maximum for

A. Gas engine

B. Petrol engine

C. Steam engine

D. Reversible engine

Answer: D

209. The amount of heat required to raise the temperature of the unit mass of gas through one degree at constant volume, is called

A. Specific heat at constant volume

B. Specific heat at constant pressure

C. Kilo Joule

D. None of these

Answer: A

210. Diesel cycle consists of following four processes

A. Two isothermal and two isentropic

B. Two isentropic and two constant volumes

C. Two isentropic, one constant volume and one constant pressure

D. Two isentropic and two constant pressures

Answer: C

211. If both Stirling and Carnot cycles operate within the same temperature limits, then efficiency of Stirling cycle as compared to Carnot cycle

A. More

B. Less

C. Equal

D. Depends on other factors

Answer: C

212. Stirling and Ericsson cycles are

A. Reversible cycles

B. Irreversible cycles

C. Semi-reversible cycles

D. Adiabatic irreversible cycles

Answer: A

213. A cycle consisting of two adiabatic and two constant pressure processes is known as

A. Otto cycle

B. Ericsson cycle

C. Joule cycle

D. Stirling cycle

Answer: C

214. Reversed joule cycle is called

A. Carnot cycle

B. Rankine cycle

C. Brayton cycle

D. Bell Coleman cycle

Answer: C

215. One kg of carbon monoxide requires _________kg of oxygen to produce 11/7 kg of carbon dioxide gas.

A. 11/7

B. 9/7

C. 4/7

D. All of the above

Answer: C

216. The absolute zero temperature is taken as

A. 237°C

B. -273°C

C. -237°C

D. 273°C

Answer: B

217. Brayton cycle consists’ of following four processes

A. Two isothermal and two isentropic

B. Two isentropic and two constant volumes

C. Two isentropic, one constant volume and one constant pressure

D. Two isentropic and two constant pressures

Answer: D

218. Which of the following cycles is not a reversible cycle?

A. Carnot

B. Ericsson

C. Stirling

D. None of the above

Answer: D

219. The cycle in which heat is supplied at constant volume and rejected at constant pressure is known as

A. Dual combustion cycle

B. Diesel cycle

C. Atkinson cycle

D. Rankine cycle

Answer: C

220. The efficiency of Diesel cycle with decrease in cut-off

A. Increases

B. Decreases

C. First increases and then decreases

D. First decreases and then increases

Answer: A

221. Which of the following cycles has maximum efficiency?

A. Rankine

B. Stirling

C. Carnot

D. Brayton

Answer: C

222. Which of the following is correct?

A. Gauge pressure = Absolute pressure + Atmospheric pressure

B. Absolute pressure = Gauge pressure + Atmospheric pressure

C. Absolute pressure = Gauge pressure – Atmospheric pressure

D. Atmospheric pressure = Absolute pressure + Gauge pressure

Answer: B

223. The efficiency and work ratio of a simple gas turbine cycle are

A. Very low

B. Low

C. High

D. Very high

Answer: A

224. The ideal efficiency of a Brayton cycle without regeneration, with increase in pressure ratio will

A. Increase

B. Decrease

C. Remain unchanged

D. Increase/decrease depending on application

Answer: A

225. The ideal efficiency of a Brayton cycle with regeneration, with increase in pressure ratio will

A. Increase

B. Decrease

C. Remain unchanged

D. Increase/decrease depending on application

Answer: B

226. The following cycle is used for air craft refrigeration

A. Brayton cycle

B. Joule cycle

C. Carnot cycle

D. Reversed Brayton cycle

Answer: D

227. A cycle consisting of __________ and two isothermal processes is known as Stirling cycle.

A. Two constant pressure

B. Two constant volume

C. Two isentropic

D. One constant pressure, one constant volume

Answer: B

228. The condition for the reversibility of a cycle is

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

B. All the processes, taking place in the cycle of operation, must be extremely slow

C. The working parts of the engine must be friction free

D. All of the above

Answer: D

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

A. Positive

B. Negative

C. Positive or negative

D. None of these

Answer: A

230. The throttling process is __________ process.

A. Reversible

B. Irreversible

C. Reversible or irreversible

D. None of these

Answer: B

231. The isothermal and adiabatic processes are regarded as

A. Reversible process

B. Irreversible process

C. Reversible or irreversible process

D. None of these

Answer: A

232. For the constant pressure and heat input, the air standard efficiency of gas power cycle is in the order

A. Dual cycle, Diesel cycle, Otto cycle

B. Otto cycle, Diesel cycle, Dual cycle

C. Dual cycle, Otto cycle, Diesel cycle

D. Diesel cycle, Otto cycle, Dual cycle

Answer: A

233. The general gas equation is (where p = Pressure, v = Volume, m = mass, T = Absolute temperature, and R = Gas constant)

A. pv = mRT

B. pv = RTm

C. pvm = C

D. pv = (RT)m

Answer: A

234. For the same maximum pressure and temperature,

A. Otto cycle is more efficient than Diesel cycle

B. Diesel cycle is more efficient than Otto cycle

C. Dual cycle is more efficient than Otto and Diesel cycles

D. Dual cycle is less efficient than Otto and Diesel cycles

Answer: B

235. Charles’ law states that all perfect gases change in volume by __________ of its original volume at 0°C for every 1°C change in temperature, when pressure remains constant.

A. 1/27th

B. 1/93th

C. 1/173th

D. 1/273th

236. A mixture of gas expands from 0.03 m3 to 0.06 m3 at a constant pressure of 1 MPa and absorbs 84 kJ of heat during the process. The change in internal energy of the mixture is

A. 30 kJ

B. 54 kJ

C. 84 kJ

D. 114 kJ

Answer: B

237. The total energy of a molecule is shared equally by the various degrees of freedom possessed by it. This law is known as

A. Law of equipartition of energy

B. Law of conservation of energy

C. Law of degradation of energy

D. None of these

Answer: A

238. An isothermal process is governed by

A. Boyle’s law

B. Charles’ law

C. Gay-Lussac law

D. Avogadro’s law

Answer: A

239. A cycle consisting of one constant pressure, one constant volume and two isentropic processes is known as

A. Carnot cycle

B. Stirling cycle

C. Otto cycle

D. Diesel cycle

Answer: D

240. Which of the following statement is incorrect?

A. The liquid fuels consist of hydrocarbons

B. The liquid fuels have higher calorific value than solid fuels

C. The solid fuels have higher calorific value than liquid fuels

D. A good fuel should have low ignition point

Answer: C

241. The efficiency of Joule cycle is

A. Greater than Carnot cycle

B. Less than Carnot cycle

C. Equal to Carnot cycle

D. None of these

Answer: B

242. Otto cycle is also known as

A. Constant pressure cycle

B. Constant volume cycle

C. Constant temperature cycle

D. Constant temperature and pressure cycle

Answer: B

243. The heat and mechanical energies are mutually convertible. This statement was established by

A. Boyle

B. Charles

C. Joule

D. None of these

Answer: C

244. The heat and work are mutually convertible. This statement is called __________ law of thermodynamics.

A. Zeroth

B. First

C. Second

D. Third

Answer: B

245. The amount of heat required to raise the temperature of 1 kg of water through one Kelvin is called

A. Specific heat at constant volume

B. Specific heat at constant pressure

C. kilo-Joule

D. None of these

Answer: C

246. A path 1-2-3 is given. A system absorbs 100 kJ as heat and does 60 kJ of work while along the path 1-4-3, it does 20 kJ of work. The heat absorbed during the cycle 1-4-3 is
Question No. 05

A. -140 kJ

B. -80 kJ

C. -40 kJ

D. +60 kJ

Answer: D

247. The fuel mostly used in blast furnace for extracting pig iron from iron ores is

A. Hard coke

B. Soft coke

C. Pulverized coal

D. Bituminous coal

Answer: A

248. Carnot cycle consists of

A. Two constant volume and two isentropic processes

B. Two isothermal and two isentropic processes

C. Two constant pressure and two isentropic processes

D. One constant volume, one constant pressure and two isentropic processes

Answer: B

249. Work-done during adiabatic expansion is given by (where p1 v1, T1 = Pressure, volume and temperature for the initial condition of gas, p2, v2, T2 = Corresponding values for the final condition of gas, R = Gas constant, and γ = Ratio of specific heats)

A. (p1 v1 – p2, v2)/(γ – 1)

B. [m R (T1 – T2)] /(γ – 1)

C. [m R T1/(γ – 1)][1 – (p2, v2 /p1 v1)]

D. All of these

Answer: D

250. In a free expansion process,

A. W1 – 2 = 0

B. Q1 – 2 = 0

C. dU = 0

D. All of these

Answer: D

251. When the gas is heated at constant volume, the heat supplied

A. Increases the internal energy of the gas and increases the temperature of the gas

B. Does some external work during expansion

C. Both A. and B.

D. None of these

Answer: A

252. Carnot cycle has maximum efficiency for

A. Petrol engine

B. Diesel engine

C. Reversible engine

D. Irreversible engine

Answer: C

253. The heat supplied to the gas at constant volume is (where m = Mass of gas, cv = Specific heat at constant volume, cp = Specific heat at constant pressure, T2 – T1 = Rise in temperature, and R = Gas constant)

A. mR (T2 – T1)

B. mcv (T2 – T1)

C. mcp (T2 – T1)

D. mcp (T2 + T1)

Answer: B

254. The processes occurring in open system which permit the transfer of mass to and from the system, are known as

A. Flow processes

B. Non-flow processes

C. Adiabatic processes

D. None of these

Answer: A

255. Stirling and Ericsson cycles are

A. Reversible cycles

B. Irreversible cycles

C. Semi-reversible cycles

D. Quasi-static cycles

Answer: A

256. In an isothermal process,

A. There is no change in temperature

B. There is no change in enthalpy

C. There is no change in internal energy

D. All of these

Answer: D

257. When the expansion or compression takes place according to the law pvn = C, the process is known as

A. Isothermal process

B. Adiabatic process

C. Hyperbolic process

D. Polytropic process

Answer: D

258. The general law of expansion or compression is pvn = C, The process is said to be hyperbolic, if n is equal to

A. 0

B. 1

C. γ

D. ∝

Answer: B

259. One kilowatt is equal to

A. 1 N-m/s

B. 100 N-m

C. 1000 N-m/s

D. 1 × 106 N-m/s

Answer: C

260. The __________ states that change of internal energy of a perfect gas is directly proportional to the change of temperature.

A. Boyle’s law

B. Charle’s law

C. Gay-Lussac law

D. Joule’s law

Answer: D

261. The amount of heat required to raise the temperature of __________ water through one degree is called kilojoules.

A. 1 g

B. 10 g

C. 100 g

D. 1000 g

Answer: D

262. The work ratio of a gas turbine plant is given by

A. (Net work output)/(Work-done by the turbine)

B. (Net work output)/(Heat supplied)

C. (Actual temperature drop)/(Isentropic temperature drop)

D. (Isentropic increase in temperature)/(Actual increase in temperature)

Answer: A

263. The variables which control the physical properties of a perfect gas are

A. Pressure exerted by the gas

B. Volume occupied by the gas

C. Temperature of the gas

D. All of these

Answer: D

264. An open system is one in which

A. Heat and work crosses the boundary of the system, but the mass of the working substance does not crosses the boundary of the system

B. Mass of the working substance crosses the boundary of the system but the heat and work does not crosses the boundary of the system

C. Both the heat and work as well as mass of the working substance crosses the boundary of the system

D. Neither the heat and work nor the mass of the working substance crosses the boundary of the system

Answer: C

265. Which of the following statement is correct?

A. The increase in entropy is obtained from a given quantity of heat at a low temperature.

B. The change in entropy may be regarded as a measure of the rate of the availability or unavailability of heat for transformation into work.

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

D. All of the above

Answer: D

266. The calorific value of gaseous fuel is expressed in

A. kJ

B. kJ/kg

C. kJ/m2

D. kJ/m3

Answer: D

267. Which of the following is the correct statement of the second law of thermodynamics?

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

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

C. There is a definite amount of mechanical energy, which can be obtained from a given quantity of heat energy.

D. All of the above

Answer: D

268. The ratio of specific heat at constant pressure (cp) and specific heat at constant volume (cv) is

A. Equal to one

B. Less than one

C. Greater than one

D. None of these

Answer: C

269. The expansion ratio (r) is the ratio of (where v1 = Volume at the beginning of expansion, and v2 = Volume at the end of expansion)

A. v1/v2

B. v2/v1

C. (v1 + v2)/v1

D. (v1 + v2)/v2

Answer: B

270. Coke is produced

A. When coal is first dried and then crushed to a fine powder by pulverizing machine

B. From the finely ground coal by molding under pressure with or without a binding material

C. When coal is strongly heated continuously for 42 to 48 hours in the absence of air in a closed vessel

D. By heating wood with a limited supply of air to a temperature not less than 280°C

Answer: C

271. The hard coke is obtained when carbonization of coal is carried out at

A. 300° to 500°C

B. 500° to 700°C

C. 700° to 900°C

D. 900° to 1100°C

Answer: D

272. Energy can neither be created nor destroyed, but it can be transformed from one form to another. This statement is known as

A. Zeroth law of thermodynamics

B. First law of thermodynamics

C. Second law of thermodynamics

D. Kinetic theory of gases

Answer: B

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

A. Increases the internal energy of the gas

B. Increases the temperature of the gas

C. Does some external work during expansion

D. Both B. and C.

Answer: D

274. When a gas is heated at constant volume

A. Its temperature will increase

B. Its pressure will increase

C. Both temperature and pressure will increase

D. Neither temperature nor pressure will increase

Answer: C

275. Which of the following is the correct statement?

A. For a given compression ratio, both Otto and Diesel cycles have the same efficiency

B. For a given compression ratio, Otto cycle is more efficient than Diesel cycle

C. For a given compression ratio, Diesel cycle is more efficient than Otto cycle

D. The efficiency of Otto or Diesel cycle has nothing to do with compression ratio

Answer: B

276. One kg of hydrogen requires 8 kg of oxygen and produces

A. 1 kg of water

B. 7 kg of water

C. 8 kg of water

D. 9 kg of water

Answer: D

277. Which of the following statement is correct according to Clausis statement of second law of thermodynamics?

A. It is possible to transfer heat from a body at a lower temperature to a body at a higher temperature.

B. 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.

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

D. None of the above

Answer: B

278. One molecule of oxygen is __________ times heavier than the hydrogen atom.

A. 12

B. 14

C. 16

D. 32

Answer: D

279. The absolute zero temperature is taken as

A. -273°C

B. 73°C

C. 237°C

D. -237°C

Answer: A

280. The efficiency and work ratio of a simple gas turbine cycle are

A. Low

B. Very low

C. High

D. Very high

Answer: B

281. The specific heat of water is

A. 1.817

B. 2512

C. 4.187

D. None of these

Answer: C

282. The specific heat at constant volume is

A. The amount of heat required to raise the temperature of unit mass of gas through one degree, at constant pressure

B. The amount of heat required to raise the temperature of unit mass of gas through one degree, at constant volume

C. The amount of heat required to raise the temperature of 1 kg of water through one degree

D. Any one of the above

Answer: B

283. For the same compression ratio, the efficiency of dual combustion cycle is

A. Greater than Diesel cycle and less than Otto cycle

B. Less than Diesel cycle and greater than Otto cycle

C. Greater than Diesel cycle

D. Less than Diesel cycle

Answer: A

284. The main cause for the irreversibility is

A. Mechanical and fluid friction

B. Unrestricted expansion

C. Heat transfer with a finite temperature difference

D. All of the above

Answer: D

285. The mass of flue gas per kg of fuel is the ratio of the

A. Mass of oxygen in 1 kg of flue gas to the mass of oxygen in 1 kg of fuel

B. Mass of oxygen in 1 kg of fuel to the mass of oxygen in 1 kg of flue gas

C. Mass of carbon in 1 kg of flue gas to the mass of carbon in 1 kg of fuel

D. Mass of carbon in 1 kg of fuel to the mass of carbon in 1 kg of flue gas

Answer: C

286. The heating of a gas at constant pressure is governed by

A. Boyle’s law

B. Charles’ law

C. Gay-Lussac law

D. Avogadro’s law

Answer: B

287. In a reversible adiabatic process, the ratio of T1/T2 is equal to

A. (p2/p1)γ – 1/ γ

B. (p1/p2)γ – 1/ γ

C. (v2/v1)γ – 1/ γ

D. (v1/v2)γ – 1/ γ

Answer: B

288. First law of thermodynamics deals with

A. Conservation of heat

B. Conservation of momentum

C. Conservation of mass

D. Conservation of energy

Answer: D

289. The value of cp/cv for air is

A. 1

B. 1.4

C. 1.45

D. 2.3

Answer: B

290. The fuel mostly used in cement industry and in metallurgical processes is

A. Wood charcoal

B. Bituminous coke

C. Pulverized coal

D. Coke

Answer: C

291. The absolute zero pressure can be attained at a temperature of

A. 0°C

B. 273°C

C. 273 K

D. None of these

Answer: D

292. Which of the following is a reversible non-flow process?

A. Isochoric process

B. Isobaric process

C. Hyperbolic process

D. All of these

Answer: D

293. Which of the following is the correct statement?

A. All the reversible engines have the same efficiency.

B. All the reversible and irreversible engines have the same efficiency.

C. Irreversible engines have maximum efficiency.

D. All engines are designed as reversible in order to obtain maximum efficiency.

Answer: C

294. In S. I. units, the value of the universal gas constant is

A. 8.314 J/kg mole-K

B. 83.14 J/kgmole-K

C. 831.4 J/kgmole-K

D. 8314 J/kgmole-K

Answer: D

295. When gas is heated at constant pressure, the heat supplied is utilized in

A. Increasing the internal energy of gas

B. Doing some external work

C. Increasing the internal energy of gas and also for doing some external work

D. None of the above

Answer: C

296. Kerosene is distilled at

A. 65° to 220°C

B. 220° to 345°C

C. 345° to 470°C

D. 470° to 550°C

Answer: B

297. In open cycle gas turbine plants

A. The indirect heat exchanger and cooler is avoided

B. Direct combustion system is used

C. A condenser is used

D. All of the above

Answer: D

298. The volumetric or molar specific heat at constant pressure is the product of

A. Molecular mass of the gas and the specific heat at constant volume

B. Atomic mass of the gas and the gas constant

C. Molecular mass of the gas and the gas constant

D. None of the above

Answer: D

299. The measurement of a thermodynamic property known as temperature is based on

A. Zeroth law of thermodynamics

B. First law of thermodynamics

C. Second law of thermodynamics

D. None of these

Answer: A

300. Which is the incorrect statement about Carnot cycle?

A. It is used as the alternate standard of comparison of all heat engines.

B. All the heat engines are based on Carnot cycle.

C. It provides concept of maximizing work output between the two temperature limits.

D. All of the above

Answer: B

301. According to Avogadro’s law

A. The product of the gas constant and the molecular mass of an ideal gas is constant

B. The sum of partial pressure of the mixture of two gases is sum of the two

C. Equal volumes of all gases, at the same temperature and pressure, contain equal number of molecules

D. All of the above

Answer: C

302. The efficiency of Stirling cycle is __________ Carnot cycle.

A. Greater than

B. Less than

C. Equal to

D. None of these

Answer: C

303. The entropy of water at 0°C is assumed to be

A. 1

B. 0

C. -1

D. 10

Answer: B

304. Producer gas is obtained by

A. Partial combustion of coal, coke, anthracite coal or charcoal in a mixed air steam blast

B. Carbonization of bituminous coal

C. Passing steam over incandescent coke

D. Passing air and a large amount of steam over waste coal at about 650°C

Answer: A

305. For the same compression ratio, the efficiency of Diesel cycle is __________ Otto cycle.

A. Greater than

B. Less than

C. Equal to

D. None of these

Answer: B

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

A. Increasing the highest temperature

B. Decreasing the highest temperature

C. Increasing the lowest temperature

D. Keeping the lowest temperature constant

Answer: A

307. The atomic mass of nitrogen is __________ oxygen.

A. Equal to

B. Less than

C. More than

D. None of these

Answer: B

308. A definite area or a space where some thermodynamic process takes place is known as

A. Thermodynamic system

B. Thermodynamic cycle

C. Thermodynamic process

D. Thermodynamic law

Answer: A

309. The absolute zero pressure will be

A. When molecular momentum of the system becomes zero

B. At sea level

C. At the temperature of – 273 K

D. At the center of the earth

Answer: A

310. The work ratio of simple gas turbine cycle depends upon

A. Maximum cycle temperature

B. Minimum cycle temperature

C. Pressure ratio

D. All of these

Answer: D

311. In closed cycle gas turbine, the air is compressed

A. Isothermally

B. Isentropically

C. Polytropically

D. None of these

Answer: B

312. The thermal efficiency of an ideal gas turbine plant is given by (where r = Pressure ratio)

A. rγ – 1

B. 1 – rγ – 1

C. 1 – (1/r) γ/γ – 1

D. 1 – (1/r) γ – 1/ γ

Answer: D

313. A process of heating crude oil to a high temperature under a very high pressure to increase the yield of lighter distillates, is known as

A. Cracking

B. Carbonization

C. Fractional distillation

D. Full distillation

Answer: A

314. One kg of carbon monoxide requires 4/7 kg of oxygen and produces

A. 11/3 kg of carbon dioxide gas

B. 7/3 kg of carbon monoxide gas

C. 11/7 kg of carbon dioxide gas

D. 8/3 kg of carbon monoxide gas

Answer: C

315. Petrol is distilled at

A. 65° to 220°C

B. 220° to 345°C

C. 345° to 470°C

D. 470° to 550°C

Answer: A

316. The air standard efficiency of an Otto cycle is given by (where r = Compression ratio, and γ = Ratio of specific heats)

A. 1 – rγ – 1

B. 1 + rγ – 1

C. 1 – (1/ rγ – 1)

D. 1 + (1/ rγ – 1)

Answer: C

317. Mond gas is obtained by

A. Partial combustion of coal, coke, anthracite coal or charcoal in a mixed air steam blast

B. Carbonization of bituminous coal

C. Passing steam over incandescent coke

D. Passing air and a large amount of steam over waste coal at about 650°C

Answer: D

318. Which of the following gas has a minimum molecular mass?

A. Oxygen

B. Nitrogen

C. Hydrogen

D. Methane

Answer: C

319. The efficiency of Diesel cycle increases with

A. Decrease in cut-off

B. Increase in cut-off

C. Constant cut-off

D. None of these

Answer: A

320. An adiabatic process is one in which

A. No heat enters or leaves the gas

B. The temperature of the gas changes

C. The change in internal energy is equal to the mechanical work-done

D. All of the above

Answer: D

321. The distillation carried out in such a way that the liquid with the lowest boiling point is first evaporated and re-condensed, then the liquid with the next higher boiling point is then evaporated and re-condensed, and so on until all the available liquid fuels are separately recovered in the sequence of their boiling points. Such a process is called

A. Cracking

B. Carbonization

C. Fractional distillation

D. Full distillation

Answer: C

322. A process, in which the temperature of the working substance remains constant during its expansion or compression, is called

A. Isothermal process

B. Hyperbolic process

C. Adiabatic process

D. Polytropic process

Answer: A

323.When two bodies are in thermal equilibrium with a third body, they are also in thermal equilibrium with each other. This statement is called

A. Zeroth law of thermodynamics

B. First law of thermodynamics

C. Second law of thermodynamics

D. Kelvin Planck’s law

Answer: A

324. Which of the following has the highest calorific value?

A. Peat

B. Lignite

C. Bituminous coal

D. Anthracite coal

Answer: D

325. Stirling cycle consists of

A. Two constant volume and two isentropic processes

B. Two constant volume and two isothermal processes

C. Two constant pressure and two isothermal processes

D. One constant volume, one constant pressure and two isentropic processes

Answer: B

326. Reversed Joule cycle is known as

A. Carnot cycle

B. Bell-Coleman cycle

C. Rankine cycle

D. Stirling cycle

Answer: B

327. Which of the following statement is correct?

A. The heat and work are boundary phenomena

B. The heat and work represent the energy crossing the boundary of the system

C. The heat and work are path functions

D. All of the above

Answer: D

328. The oxygen atom is ________ times heavier than the hydrogen atom.

A. 2

B. 8

C. 16

D. 32

Answer: C

329. The heat flows from a cold body to a hot body with the aid of an external source. This statement is given by

A. Kelvin

B. Joule

C. Clausis

D. Gay-Lussac

Answer: C

330. The smallest quantity of a substance, which can exist by itself in a chemically recognizable form is known as

A. Element

B. Compound

C. Atom

D. Molecule

Answer: D

331. The behavior of super-heated vapour is similar to that of

A. Perfect gas

B. Air

C. Steam

D. Ordinary gas

Answer: A

332. Relation between cp and cv is given by (where cp = Specific heat at constant pressure, cv = Specific heat at constant volume, γ = cp/cv, known as adiabatic index, and R = Gas constant)

A. cv/ cp =R

B. cp – cv = R

C. cv = R/ γ-1

D. Both B. and C.

Answer: D

333. A cycle consisting of two constant pressure and two isentropic processes is known as

A. Carnot cycle

B. Stirling cycle

C. Otto cycle

D. None of these

Answer: D

334. The atomic mass of sulphur is

A. 12

B. 14

C. 16

D. 32

Answer: D

335. The efficiency of Carnot cycle depends upon

A. Temperature limits

B. Pressure ratio

C. Volume compression ratio

D. Cut-off ratio and compression ratio

Answer: A

336. Otto cycle efficiency is higher than Diesel cycle efficiency for the same compression ratio and heat input because in Otto cycle

A. Combustion is at constant volume

B. Expansion and compression are isentropic

C. Maximum temperature is higher

D. Heat rejection is lower

Answer: D

337. The value of 1 mm of Hg is equal to

A. 1.333 N/m2

B. 13.33 N/m2

C. 133.3 N/m2

D. 1333 N/m2

Answer: C

338. Carbonization of coal consists of

A. Drying and crushing the coal to a fine powder

B. Moulding the finely ground coal under pressure with or without a binding material

C. Heating the wood with a limited supply of air to temperature not less than 280°C

D. None of the above

Answer: D

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

A. Heat absorbed

B. Heat rejected

C. Either A. or B.

D. None of these

Answer: C

340. One Joule (J) is equal to

A. 1 N-m

B. 1 kN-m

C. 10 N-m/s

D. 10 kN-m/s

Answer: A

341. According to First law of thermodynamics,

A. Total internal energy of a system during a process remains constant

B. Total energy of a system remains constant

C. Work-done by a system is equal to the heat transferred by the system

D. Internal energy, enthalpy and entropy during a process remain constant

Answer: B

342. When wood is heated with a limited supply of air to a temperature not less than 280°C, the resulting fuel is

A. Coke

B. Wood charcoal

C. Bituminous coal

D. Briquetted coal

Answer: B

343. The heat energy stored in the gas and used for raising the temperature of the gas is known as

A. External energy

B. Internal energy

C. Kinetic energy

D. Molecular energy

Answer: B

344. Which of the following statement is wrong?

A. The closed cycle gas turbine plants are external combustion plants.

B. In the closed cycle gas turbine, the pressure range depends upon the atmospheric pressure.

C. The advantage of efficient internal combustion is eliminated as the closed cycle has an external surface.

D. In open cycle gas turbine, atmosphere acts as a sink and no coolant is required.

Answer: B

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

A. Absolute scale of temperature

B. Absolute zero temperature

C. Absolute temperature

D. None of these

Answer: B

346. One kg of ethylene (C2H4) requires 2 kg of oxygen and produces 22/7 kg of carbon dioxide and __________ kg of water or steam.

A. 9/7

B. 11/7

C. 7/4

D. 11/4

Answer: A

347. According to Regnault’s law, the specific heat at constant pressure (cp) and specific heat at constant volume (cv) _________ with the change in pressure and temperature of the gas.

A. Change

B. Do not change

C. Both A. and B.

D. None of these

Answer: B

348. Which of the following is correct?

A. Absolute pressure = Gauge pressure + Atmospheric pressure

B. Gauge pressure = Absolute pressure + Atmospheric pressure

C. Atmospheric pressure = Absolute pressure + Gauge pressure

D. Absolute pressure = Gauge pressure – Atmospheric pressure

Answer: A

349. The general gas energy equation is (where Q1 – 2 = Heat supplied, dU = Change in internal energy, and W1 – 2 = Work done in heat units)

A. Q1 – 2 = dU + W1 – 2

B. Q1 – 2 = dU – W1 – 2

C. Q1 – 2 = dU/W1 – 2

D. Q1 – 2 = dU × W1 – 2

Answer: A

350. The natural solid fuel is

A. Wood

B. Coke

C. Anthracite coal

D. Pulverized coal

Answer: A

351. In an ideal gas turbine plant, it is assumed that the compression and expansion processes are

A. Isothermal

B. Isentropic

C. Polytropic

D. None of these

Answer: B

352. The natural petroleum may be separated into

A. Petrol

B. Kerosene

C. Fuel oil

D. Lubricating oil

Answer: D

353. According to Kelvin-Planck’s statement of second law of thermodynamics,

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

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

C. It is impossible to construct a device which operates in a cyclic process and produces no effect other than the transfer of heat from a cold body to a hot body

D. None of the above

Answer: A

354. The pressure exerted by an ideal gas is ________ of the kinetic energy of all the molecules contained in a unit volume of gas.

A. One-half

B. One-third

C. Two-third

D. Three-fourth

Answer: C

355. When a gas is heated, change takes place in

A. Pressure

B. Volume

C. Temperature

D. All of these

Answer: D

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

A. Enthalpy

B. Internal energy

C. Entropy

D. External energy

Answer: C

357. The fuel mostly used in steam boilers is

A. Brown coal

B. Peat

C. Coking bituminous coal

D. Non-coking bituminous coal

Answer: D

358. The heat absorbed or rejected by the working substance is given by (where ds = Increase or decrease of entropy, T = Absolute temperature, and dQ = Heat absorbed or rejected)

A. δQ = T.ds

B. δQ = T/ds

C. dQ = ds/T

D. None of these

Answer: A

359. The gas constant (R) is equal to the

A. Sum of two specific heats

B. Difference of two specific heats

C. Product of two specific heats

D. Ratio of two specific heats

Answer: B

360. A process, in which the gas is heated or expanded in such a way that the product of its pressure and volume remains constant, is called

A. Isothermal process

B. Hyperbolic process

C. Adiabatic process

D. Polytropic process

Answer: B

361. The efficiency of the dual combustion cycle for the same compression ratio is __________ Diesel cycle.

A. Greater than

B. Less than

C. Equal to

D. None of these

Answer: A

362. Those substances which have so far not been resolved by any means into other substances of simpler form are called

A. Elements

B. Compounds

C. Atoms

D. Molecules

Answer: A

363. The most probable velocity of the gas molecules is given by

A. √(KT/m)

B. √(2KT/m)

C. √(3KT/m)

D. √(5KT/m)

Answer: B

364. The sum of internal energy (U) and the product of pressure and volume (p.v) is known as

A. Work-done

B. Entropy

C. Enthalpy

D. None of these

Answer: C

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

A. Vapour

B. Perfect gas

C. Air

D. Steam

Answer: B

366. The root mean square velocity of the gas molecules is given by (where k = Boltzmann’s constant, T = Absolute temperature, and m = Mass of one molecule of a gas)

A. √(KT/m)

B. √(2KT/m)

C. √(3KT/m)

D. √(5KT/m)

Answer: C

367. When a perfect gas is expanded through an aperture of minute dimensions, the process is known as

A. Isothermal process

B. Adiabatic process

C. Free expansion process

D. Throttling process

Answer: D

368. A process, in which the working substance neither receives nor gives out heat to its surroundings during its expansion or compression, is called

A. Isothermal process

B. Hyperbolic process

C. Adiabatic process

D. Polytropic process

Answer: C

369. The ratio of specific heat at constant pressure (cp) and specific heat at constant volume (cv) is always __________ one.

A. Equal to

B. Less than

C. Greater than

D. None of these

Answer: C

370. Select the correct statement as per Charles’ law

A. p.v = constant, if T is kept constant

B. v/T = constant, if p is kept constant

C. p/T = constant, if v is kept constant

D. T/p = constant, if v is kept constant

Answer: B

371. A close cycle gas turbine gives __________ efficiency as compared to an open cycle gas turbine.

A. Same

B. Lower

C. Higher

D. None of these

Answer: C

372. According to Avogadro’s law, the density of any two gases is __________ their molecular masses, if the gases are at the same temperature and pressure.

A. Equal to

B. Directly proportional to

C. Inversely proportional to

D. None of these

Answer: B

373. During which of the following process does heat rejection takes place in Carnot cycle?

A. Isothermal expansion

B. Isentropic expansion

C. Isothermal compression

D. Isentropic compression

Answer: C

374. A tri-atomic molecule consists of __________ atoms.

A. One

B. Two

C. Three

D. Four

Answer: C

375. Which of the following has the minimum atomic mass?

A. Oxygen

B. Sulphur

C. Nitrogen

D. Carbon

Answer: D

376. The mass of carbon per kg of flue gas is given by

A. (11/3) CO2 + (3/7) CO

B. (3/7) CO2 + (11/3) CO

C. (7/3) CO2 + (3/11) CO

D. (3/11) CO2 + (7/3) CO

Answer: A

377. When a system changes its state from one equilibrium state to another equilibrium state, then the path of successive states through which the system has passed, is known as

A. Thermodynamic law

B. Thermodynamic process

C. Thermodynamic cycle

D. None of these

Answer: B

378. When the gas is cooled at constant pressure,

A. Its temperature increases but volume decreases

B. Its volume increases but temperature decreases

C. Both temperature and volume increases

D. Both temperature and volume decreases

Answer: D

379. Otto cycle consists of

A. Two constant volume and two isentropic processes

B. Two constant pressure and two isentropic processes

C. Two constant volume and two isothermal processes

D. One constant pressure, one constant volume and two isentropic processes

Answer: A

380. The efficiency of a gas turbine is given by

A. (Net work output)/(Work-done by the turbine)

B. (Net work output)/(Heat supplied)

C. (Actual temperature drop)/(Isentropic temperature drop)

D. (Isentropic increase in temperature)/(Actual increase in temperature)

Answer: B

381. An open cycle gas turbine works on

A. Carnot cycle

B. Otto cycle

C. Joule’s cycle

D. Stirling cycle

Answer: C

382. If the value of n = 0 in the equation pvn = C, then the process is called

A. Constant volume process

B. Adiabatic process

C. Constant pressure process

D. Isothermal process

Answer: C

383. The efficiency of Ericsson cycle is __________ Carnot cycle.

A. Greater than

B. Less than

C. Equal to

D. None of these

Answer: C

384. The mass of excess air supplied is equal to

A. (23/100) × Mass of excess carbon

B. (23/100) × Mass of excess oxygen

C. (100/23) × Mass of excess carbon

D. (100/23) × Mass of excess oxygen

Answer: D

385. The universal gas constant (or molar constant) of a gas is the product of

A. Molecular mass of the gas and the gas constant

B. Atomic mass of the gas and the gas constant

C. Molecular mass of the gas and the specific heat at constant pressure

D. Molecular mass of the gas and the specific heat at constant volume

Answer: A

386. The molecular mass expressed in gram (i.e. 1 g – mole) of all gases, at N. T. P., occupies a volume of

A. 0.224 liters

B. 2.24 liters

C. 22.4 liters

D. 224 liters

Answer: C

387. The standard value of atmospheric pressure taken at sea level is

A. 1.013 bar

B. 760 mm of Hg

C. 1013 × 102 N/m2

D. All of these

Answer: D

388. The process is adiabatic, if the value of n in the equation pvn = C, is

A. Zero

B. One

C. γ

D. ∝

Answer: C

389. The polytropic index (n) is given by

A. log (p1p2)/log (v1v2)

B. log (p2/ p1)/log (v1/ v2)

C. log (v1/ v2)/ log (p1/p2)

D. log [(p1v1)/(p2v2)]

Answer: B

390. Which of the following gas is mostly used in town for street and domestic lighting and heating?

A. Producer gas

B. Coal gas

C. Mond gas

D. Coke oven gas

Answer: B

391. In an irreversible process, there is a

A. Loss of heat

B. No loss of heat

C. Gain of heat

D. No gain of heat

Answer: A

392. The general law for the expansion or compression of gases, is

A. pv = C

B. pv = m R T

C. pvn = C

D. pvγ = C

Answer: C

393. The principal constituents of a fuel are

A. Carbon and hydrogen

B. Oxygen and hydrogen

C. Sulphur and oxygen

D. Sulphur and hydrogen

Answer: A

394. The reading of the pressure gauge fitted on a vessel is 25 bar. The atmospheric pressure is 1.03 bar and the value of ‘g’ is 9.81 m/s2. The absolute pressure in the vessel is

A. 23.97 bar

B. 25 bar

C. 26.03 bar

D. 34.81 bar

Answer: C

395. High air-fuel ratio in gas turbines

A. Increases power output

B. Improves thermal efficiency

C. Reduces exhaust temperature

D. Do not damage turbine blades

Answer: C

396. The ratio of root mean square velocity to average velocity of gas molecules at a particular temperature is

A. 0.086

B. 1.086

C. 1.086

D. 4.086

Answer: B

397. One molecule of oxygen consists of __________ atoms of oxygen.

A. 2

B. 4

C. 8

D. 16

Answer: A

398. A series of operations, which takes place in a certain order and restore the initial conditions at the end, is known as

A. Reversible cycle

B. Irreversible cycle

C. Thermodynamic cycle

D. None of these

Answer: C

399. The compression ratio for petrol engines is

A. 3 to 6

B. 5 to 8

C. 15 to 20

D. 20 to 30

Answer: B

400. The hyperbolic process is governed by

A. Boyle’s law

B. Charles’ law

C. Gay-Lussac law

D. Avogadro’s law

Answer: A

401. According to kinetic theory of gases, the velocity of molecules __________ with the increase in temperature.

A. Remains constant

B. Increases

C. Decreases

D. None of these

Answer: B

402. The ultimate analysis of coal consists of the determination of the percentage of

A. Carbon

B. Hydrogen and nitrogen

C. Sulphur and ash

D. All of these

Answer: D

403. The heating of gas at constant volume is governed by

A. Boyle’s law

B. Charles’ law

C. Gay-Lussac law

D. Avogadro’s law

Answer: C

404. In a steady flow process, the ratio of

A. Heat transfer is constant

B. Work transfer is constant

C. Mass flow at inlet and outlet is same

D. All of these

Answer: D

405. The entropy may be expressed as a function of

A. Pressure and temperature

B. Temperature and volume

C. Heat and work

D. All of these

Answer: A

406. The gas constant (R) is equal to the __________ of two specific heats.

A. Sum

B. Difference

C. Product

D. Ratio

Answer: B

407. Work-done in a free expansion process is

A. Zero

B. Minimum

C. Maximum

D. Positive

Answer: A

408. Kelvin-Planck’s law deals with

A. Conservation of work

B. Conservation of heat

C. Conversion of heat into work

D. Conversion of work into heat

Answer: C

409. Second law of thermodynamics defines

A. Heat

B. Work

C. Internal energy

D. Entropy

Answer: D

410. Which of the following gas has the highest calorific value?

A. Coal gas

B. Producer gas

C. Mond gas

D. Blast furnace gas

Answer: A

411. One reversible heat engine operates between 1600 K and T2 K and another reversible heat engine operates between T2 K and 400 K. If both the engines have the same heat input and output, then temperature T2 is equal to

A. 800 K

B. 1000 K

C. 1200 K

D. 1400 K

Answer: A

412. According to Kelvin-Planck’s statement, a perpetual motion of the __________ is impossible.

A. First kind

B. Second kind

C. Third kind

D. None of these

Answer: B

413. The value of one bar (in S. I. units) is equal to

A. 1 × 102 N/m2

B. 1 × 103 N/m2

C. 1 × 104 N/m2

D. 1 × 105 N/m2

Answer: D

414. The value of gas constant (R) in S. I. units is

A. 0.287 J/kgK

B. 2.87 J/kgK

C. 28.7 J/kgK

D. 287 J/kgK

Answer: D

415. The compression ratio for Diesel engines is

A. 3 to 6

B. 5 to 8

C. 15 to 20

D. 20 to 30

Answer: C

416. The ratio of molar specific heats for mono-atomic gas is

A. 1

B. 1.4

C. 1.67

D. 1.87

Answer: C

418. Steam coal is a

A. Pulverized coal

B. Brown coal

C. Coking bituminous coal

D. Non-coking bituminous coal

Answer: D

419. When a gas is heated at constant pressure

A. Its temperature will increase

B. Its volume will increase

C. Both temperature and volume will increase

D. Neither temperature not volume will increase

Answer: C

420. Diesel cycle consists of __________ processes.

A. Two constant volume and two isentropic

B. Two constant pressure and two isentropic

C. Two constant volume and two isothermal

D. One constant pressure, one constant volume and two isentropic

Answer: D

421. Select the wrong statement

A. A Joule cycle consists of two constant volume and two isentropic processes.

B. An Otto cycle consists of two constant volume and two isentropic processes.

C. An Ericsson cycle consists of two constant pressure and two isothermal processes.

D. All of the above

Answer: A

422. The compression ratio is the ratio of

A. Swept volume to total volume

B. Total volume to swept volume

C. Swept volume to clearance volume

D. Total volume to clearance volume

Answer: D

423. One kg of carbon requires 4/3 kg of oxygen and produces __________ kg of carbon monoxide gas.

A. 8/3

B. 11/3

C. 11/7

D. 7/3

Answer: D

424. The efficiency of Diesel cycle approaches to Otto cycle efficiency when

A. Cut-off is increased

B. Cut-off is decreased

C. Cut-off is zero

D. Cut-off is constant

Answer: C

425. The behavior of a perfect gas, undergoing any change in the variables which control physical properties, is governed by

A. Boyle’s law

B. Charles’ law

C. Gay-Lussac law

D. All of these

Answer: D

426. The __________ is obtained when carbonization of coal is carried out at 500° to 700° C.

A. Soft coal

B. Hard coal

C. Pulverized coal

D. Bituminous coal

Answer: A

427. A molecule consisting of one atom is known as

A. Mono-atomic

B. Di-atomic

C. Tri-atomic

D. Poly-atomic

Answer: A

428. The unit of energy is S. I. units is

A. Joule (J)

B. Joule meter (Jm)

C. Watt (W)

D. Joule/meter (J/m)

Answer: A

429. The amount of heat generated per kg of fuel is known as

A. Calorific value

B. Heat energy

C. Lower calorific value

D. Higher calorific value

Answer: A

430. The entropy __________ in an irreversible cyclic process.

A. Remains constant

B. Decreases

C. Increases

D. None of these

Answer: C

431. For a perfect gas, according to Boyle’s law (where p = Absolute pressure, v = Volume, and T = Absolute temperature)

A. p v = constant, if T is kept constant

B. v/T = constant, if p is kept constant

C. p/T = constant, if v is kept constant

D. T/p = constant, if v is kept constant

Answer: A

432. Which of the following is the extensive property of a thermodynamic system?

A. Pressure

B. Volume

C. Temperature

D. Density

Answer: B

433. The increase in entropy of a system represents

A. Increase in availability of energy

B. Increase in temperature

C. Decrease in pressure

D. Degradation of energy

Answer: D

434. A cycle consisting of two isothermal and two isentropic processes, is known as

A. Carnot cycle

B. Stirling cycle

C. Ericsson cycle

D. Joule cycle

Answer: A

435. When coal is strongly heated continuously for 42 to 48 hours in the absence of air in a closed vessel, the process is known as __________ of fuel.

A. Atomization

B. Carbonization

C. Combustion

D. None of these

Answer: B

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

A. Volume

B. Temperature

C. Mass

D. Energy

Answer: B

437. In an extensive property of a thermodynamic system

A. Extensive heat is transferred

B. Extensive work is done

C. Extensive energy is utilized

D. None of these

Answer: D

438. All perfect gases change in volume by 1/273th of its original volume at 0°C for every 1°C change in temperature, when the pressure remains constant. This statement is called

A. Boyle’s law

B. Charles’ law

C. Gay-Lussac law

D. Joule’s law

Answer: B

439. When cut-off ratio is __________ the efficiency of Diesel cycle approaches to Otto cycle efficiency.

A. Zero

B. 1/5

C. 4/5

D. 1

Answer: A

440. The atomic mass of oxygen is

A. 8

B. 18

C. 16

D. 32

Answer: C

441. The gas turbine cycle with regenerator improves

A. Thermal efficiency

B. Work ratio

C. Avoids pollution

D. None of these

Answer: A

442. Which of the following process can be made reversible with the help of a regenerator?

A. Constant pressure process

B. Constant volume process

C. Constant pvn process

D. All of these

Answer: D

443. One kg of carbon produces __________ kg of carbon dioxide.

A. 3/7

B. 7/3

C. 11/3

D. 3/11

Answer: C

444. The kinetic energy per kg molecule of any gas at absolute temperature T is equal to (where Ru = Universal gas constant)

A. Ru × T

B. 1.5 Ru × T

C. 2 Ru × T

D. 3 Ru × T

Answer: B

445. If in the equation pvn = C, the value of n = ∝, then the process is called

A. Constant volume process

B. Adiabatic process

C. Constant pressure process

D. Isothermal process

Answer: A

446. The value of specific heat at constant pressure (cp) is __________ that of at constant volume (cv).

A. Less than

B. Equal to

C. More than

D. None of these

Answer: C

447. One kg of carbon monoxide requires __________ kg of oxygen to produce 11/7 kg of carbon dioxide gas.

A. 4/7

B. 11/4

C. 9/7

D. All of these

Answer: A

448. The efficiency of Diesel cycle depends upon

A. Temperature limits

B. Pressure ratio

C. Compression ratio

D. Cut-off ratio and compression ratio

Answer: D

449. The efficiency of the Carnot cycle is (where T1 and T2 = Highest and lowest temperature during the cycle)

A. (T1/T2) – 1

B. 1 – (T1/T2)

C. 1 – (T2/T1)

D. 1 + (T2/T1)

Answer: C

450. The gas in cooling chamber of a closed cycle gas turbine is cooled at

A. Constant volume

B. Constant temperature

C. Constant pressure

D. None of these

Answer: C

451. When coal is first dried and then crushed to a fine powder by pulverizing machine, the resulting fuel is called

A. Wood charcoal

B. Bituminous coal

C. Briquetted coal

D. None of these

Answer: D

452. The thermodynamic difference between a Rankine cycle working with saturated steam and the Carnot cycle is that

A. Carnot cycle can’t work with saturated steam

B. Heat is supplied to water at temperature below the maximum temperature of the cycle

C. A Rankine cycle receives heat at two places

D. Rankine cycle is hypothetical

Answer: B

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