1. The amount of heat absorbed by a system at lower temperature is
Correct : C. work supplied
2. Tds equation is
Correct : A. a) tds=cvdt + t
3. In an ideal gas the partial pressure of a component is
Correct : B. directly proportional to the mole fraction
4. The value of the univesal gas constant is
Correct : D. 8.314 kj/kg k
5. Choose the correct answer
Correct : B. a perfect gas obeys the law pv=rt & has constant specific heat
6. Boyle's law states that, when tempearture is constant, the volume of a given mass of a perfect gas
Correct : B. varies inversely as the absolute pressure
7. Charle's law states that if any gas is heated at constant pressure, its volume
Correct : A. changes directly as it absolute temperature
8. The equation of state of an ideal gas is a relationship between the variables:
Correct : C. pressure, volume & temperature
9. Joule's law states that the specific internal energy of a gas depends only on
Correct : C. the temperature of the gas
10. ………. Law states that equal volume of all gases, at the same temperature & pressure, contains equal number of molecules
Correct : C. avogadro
11. The change of entropy is considered to be ……… when heat is absorbed by the gas
Correct : A. positive
12. ………. Is one in which neither any heat enters nor leaves the system
Correct : C. isentropic process
13. Entropy of the universe
Correct : C. tends to a maximum
14. A gas can never be liquid
Correct : A. above criticaltemperature
15. Which of the following remains constant during an adiabatic expansion
Correct : A. entropy
16. In which of the following processes the change in internal energy of a gas is equal to the work done
Correct : A. adiabatic process
17. The specific heat of a gas is a function of
Correct : A. temperature only
18. In a Carnot cycle which of the following processez must be carried out at extremely slow speed?
Correct : A. isothermal compression
19. In the case of real gases, cp will be equal to cv
Correct : A. at absolute zero
20. The physical properties of a perfect gas are controlled by which of the following variables?
Correct : D. all of the above
21. Universal gas constant is defined as equal to the product of the molecular weight of the gas &
Correct : A. gas constant
22. All engineering process, strictly speaking are
Correct : D. thermodynamically inequillibrium
23. Isothermal, isobaric, isochoric & adiabatic processes, under ideal conditions, are …. Processes
Correct : D. quasi-static
24. Change of entropy depends upon which of the following?
Correct : A. change of heat
25. In a reversible adiabatic process head added is equal to
Correct : A. zero
26. During a throttling process
Correct : D. all of the above
27. Under which of the following conditions all gases behave ideally?
Correct : B. law pressure conditions
28. ……….. Is the unit of entropy
Correct : B. j/kg k
29. Internal energy & enthalpy of an ideal gas are functions of
Correct : B. temperature only
30. When two gases suddenly mix up with each other then resultant entropy of the system will
Correct : C. increase
31. On which of the following factors does air standard efficiency of a diesel cycle depend?
Correct : D. all of the above
32. Regarding enthalpy which of the following statements is incorrect?
Correct : A. it is the function of specific heat at constantvolume
33. Which of the following processes is reversible process?
Correct : A. throttling
34. Which of the following processes are reversible processes?
Correct : A. isothermal & adiabatic
35. For ……. The internal energy & enthalpy are the functions of temperature only
Correct : A. perfect gas
36. The index of compression n tends to reach ?(ratio of specific heats)
Correct : C. when process is isentropic & specific heat does not change with temperature
37. In the reversible polytropic process the value of exponent n varies between
Correct : C. 1.2 to 1.4
38. An ideal gas as compared to a real gas at very high pressure occupies
Correct : C. more volume
39. Adiabatic & isothermal processes are identical at
Correct : A. absolute zerotemperature
40. In polytropic process pv?=C the value of exponent n=±? is indicative of
Correct : C. isochoric process
41. Entropy in statistical thermodynamics is defined as
Correct : C. degree of randomness
42. A mixture of gases expands from 0.03 m³ to 0.06 m³ at a constant pressure of 1 Mpa & absorbs 84 kJ of heat during the process. The change in internal energy of the mixture is
Correct : B. 54 kj
43. Increase in entropy of a system represents
Correct : D. degradation of energy
44. Which one of the following pairs best expresses a relationship similar to that expressed in the pair 'pressure-volume' for a thermodynamic system undergoing a process?
Correct : D. temperature-entropy
45. Variations of pressure & volume at constant temperature are correlated through
Correct : B. boyle's law
46. The relationship between pressure & volume is expressed as pv?=const. Select wrong statement
Correct : C. expansion with n=? is not possible
47. A gas expands from initial condition of (p1, v1, T1) to final condition (p2, v1, T2), then according to Charle's law:
Correct : D. p1t2 = p2t1
48. Air expands from initial condition of p1, v1 to final condition of 1/2 p1, 2v1.
Choose the correct statement
Correct : C. expansion is polytropic with n= 1.2
49. Air with initial condition of p1, v1 expands to final condition of p1/2, 3v1.
The process is
Correct : A. hyperbolic
50. The internal energy of a perfect gas is a function of
Correct : D. temperature
51. During a polytropic expansion 25% of heat is converted into work while temperature of gas rises by 30 K, the specific heat of gas at constant volume is
Correct : B. 12 % w
52. During a constant pressure expansion of a gas 33.3 % heat is converted into work while the temperature rises by 20K. The specific heat of gas at constant pressure is
Correct : C. 15% w
53. During an adiabatic compression when temperature increase by 100% the pressure increases by 1000%. The ratio of specific heats, ? is
Correct : C. 1.4
54. In an constant pressure heating certain fraction of heat supplied is converted into work. If ?=1.4 this fraction is
Correct : D. 0.327
55. The area under the curve on temperature entropy diagram represents
Correct : B. heat exchanged during the process
56. The change in entropy is zero during
Correct : C. adiabatic processes
57. Choose incorrect statement
Correct : D. no work is done in constant pressure process
58. Choose the correct statement
Correct : B. entropy is an extensive property of gas derived from first law of thermodynamics
59. 1.6 Kg of air is expanded at constant pressure from 100°C to 0°C resulting in entropy change of - 2.0 J/K 3.2 Kg of air is cooled at constant volume from 100°C to 0°C with a change in entropy of -3.0 J/K. The ratio Cp/ Cv is
Correct : C. 1.4
60. Entropy at absolute zero temperature is zero for a
Correct : C. perfect crystal
61. The third law of thermodynamics
Correct : D. gives availability of heat for conversion into work
62. Entropy is called the property of a system because
Correct : A. it has same value at any two equilibrium states
63. Entropy of mixture of two gases after sudden mixing is
Correct : A. greater than
64. If a substance goes though a cycle of changes returning back to original state, the change in entropy is
Correct : B. negative
65. A sequence of operations which a gas undergoes in such a way that final state is same as original state, mahe a
Correct : D. thermodynamic cycle
66. In a reversible process
Correct : C. heat transfer takes place from surrounding to thesystem
67. Which of the following processes is very close to reversible
Correct : C. flow of a fluid in a pipe
68. A perfect gas having p1= 0.1 M/mm², v1=0.18 m³, T1=20°C is compressed to 1/10 of volume in an isothermal process. The change in entropy is
Correct : B. 141.45 j/k
69. The enthalpy of a system
Correct : B. i= internal energy + pdv
70. During a polytropic expansion work obtained is 1.8 times the heat transferred. If ?=1.4, n will be
Correct : D. 1.155
71. Which statement is wrong for throttling expansion
Correct : C. work done = 0
72. Which statement is wrong for adiabatic expansion
Correct : D. w+e = 0
73. Maximum amount of work that can be converted into heat in any process
Correct : B. depends upon how much work is lost in friction
74. The universal gas constant will be equal to difference between specific heats at constant pressure & constant volume for
Correct : C. 1 kg molecule of gas
75. Air is compressed isothermally by performing work equal to 16 KJ upon it. The change in internal energy is
Correct : B. zeroth law of thermodynamics
76. The latent heat of vapouristation at critical point is
Correct : C. equal to zero
77. Choose the correct answer
Correct : D. triple point involves equilibrium of solid, liquid & vapour phases
78. With the increase in pressure
Correct : B. boiling point of water increases & enthalpy of evaporation decreases
79. With increase in pressure
Correct : B. enthalpy of dry saturated steam decreases
80. Dryness fraction of steam is defined as
Correct : C. mass of dry steam/(mass of dry steam+mass of water vapour in suspension)
81. Only throttling calorimeter is used for measuring
Correct : B. very high dryness fraction upto 0.98
82. Rankine cycle efficiency of a good steam power plant may be in the range of
Correct : B. 35 to 45%
83. Rankine cycle operating on low pressure limit of p1 & high pressure limit p2
Correct : A. has higher thermal efficiency than the carnot cycle operating between same pressure limits
84. Rankine cycle comprises of
Correct : B. two isentropic processes & two constant pressureprocesses
85. In Rankine cycle the work output from the turbine is given by
Correct : B. change of enthalpy between inlet & outlet
86. The maximum percentage gain in Regenerative feed heating cycle thermal effciency
Correct : A. increases with number of feed heaters increasing
87. In an unsaturated air the state of a vapour is
Correct : B. superheated
88. The efficiency of the Carnot cycle may be increased by
Correct : D. both a & c
89. Most of the fossil fuel based power plants operate on
Correct : D. either rankine or brayton cycle
90. Efficiency of Rankine cycle is function of
Correct : C. both highest & lowest temperature of the cycle
91. Essential parts of a power plant operating on a Rankine cycle are
Correct : C. gine or turbine, condenser, pump &boiler
92. Correlate the following statements
i) the volume of water into which steam is condensed in condenser is very much smaller than the volume of steam before condensation
ii) the net work of a Rankine cycle is heat supplied in boiler - heat rejected to condenser - pump work
Correct : D. both i) & ii) are independently correct
93. By reducing the condenser pressure in Rankine power plant
Correct : B. work of cycle & moisture content of steam in l.p side ofturbine increase
94. Correlate the following statements
i) by reducing the condenser pressure in a Rankine cycle work output is increased
ii) increased proportion of moisture in turbine is undesirable because water particles erode the blades
Correct : A. both i) & ii) are independently true
95. Turbine blade efficiency reduces in a Rankine cycle if
Correct : C. condenser pressure decreases
96. A Rankine cycle with reheat
Correct : D. increases efficiency but reduces moisture content in l.p side of turbine
97. The main advantage of a Reheat Rankine cycle is
Correct : A. reduced moisture content in l.p side of turbine
98. A Reheat Rankine cycle
Correct : B. increases total heat produced in boiler
99. Choose the wrong statement
Correct : C. volume of steam passing through h.p side of the turbine & condenser is same in regenerative rankinecycle
100. Examine follwing two statements & choosethe correct relationship
i) for a steam power plant Rankine cycle is preferred over Carnot cycle
ii) a pump which will handle the mixture of vapour & liquid is difficult to construct
Correct : A. both i) ii) are correct & i) is the consequence of ii)