1. Efficiency of a reversible heat engine is given by
Correct : B. 1-(t2/t1)
2. For a reversible refrigerator, Coefficient of Performance is given by
Correct : A. t2/(t1-t2)
3. Entropy principle is the quantitative statement of the second law of thermodynamics.
Correct : A. true
4. Which of the following can be considered as an application of entropy principle?
Correct : D. all of the mentioned
5. The final temperatures of two bodies, initially at T1 and T2 can range from
Correct : B. (t1+t2)/2 to sqrt(t1*t2)
6. Which of the following processes exhibit external mechanical irreversibility?
Correct : C. both of the mentioned
7. Which of the following is an example of low grade energy?
Correct : D. all of the mentioned
8. Which of the following is an example of high grade energy?
Correct : D. all of the mentioned
9. The unavailable energy is the product of the lowest temperature of heat rejection and the change of entropy of system during the process of supplying heat.
Correct : A. true
10. The lowest practicable temperature of heat rejected is the
Correct : C. temperature of surroundings
11. Exergy is lost due to
Correct : D. all of the mentioned
12. Which of the following is a type of energy?
Correct : C. both of the mentioned
13. The complete conversion of heat into shaft- work is impossible.
Correct : A. true
14. Energy is said to be degraded each time it flows through a finite temperature difference.
Correct : A. true
15. When considering a finite energy source, its working fluid expands,
Correct : C. reversibly and adiabatically
16. The entropy of any closed system can increase in which if the following way?
Correct : C. both of the mentioned
17. The entropy increase due to internal irreversibility is also called entropy production or entropy generation.
Correct : A. true
18. Which of the following statement is true?
Correct : D. all of the mentioned
19. Lost work is given by
Correct : A. pdv-dw
20. Which of the following statement is false?
Correct : B. the entropy generation does not depend on the path the system follows
21. Mass and energy are conserved quantities, but entropy is generally not conserved.
Correct : A. true
22. A chip dissipates 2 kJ of electric work and rejects it as heat transfer from its surface which is at 50°C to 25°C air. How much entropy is generated outside the chip?
Correct : B. 0.519 j/k
23. Entropy increase dS of the system can be expressed as
Correct : B. ds=ds(due to external heat interaction)+ds(due to internal irreversibility)
24. If the path A causes more entropy generation than path B, then
Correct : C. both of the mentioned
25. In an open system, there is a transfer of which of the following quantity?
Correct : D. all of the mentioned
26. A chip dissipates 2 kJ of electric work and rejects it as heat transfer from its surface which is at 50°C to 25°C air. How much entropy is generated in the chip?
Correct : C. 6.19 j/k
27. 15 = 6.19 J/K.
Correct : B. 0.519 j/k
28. Second law efficiency can also be given as
Correct : D. first law efficiency / carnot efficiency
29. Second law efficiency is defined as
Correct : B. minimum exergy intake / actual exergy intake
30. For a power plant, second law efficiency can be given by desired output(W) / available energy(Wmax).
Correct : A. true
31. In case of a heat pump, second law efficiency is given as
Correct : C. (first law efficiency)*(1-to/ta)
32. Both first law efficiency and second law efficiency indicate how effectively the input has been converted into the product.
Correct : A. true
33. Which of the following curves meet at triple point?
Correct : D. fusion curve and vaporization curve and sublimation curve
34. The slope of the fusion curve for water is
Correct : A. negative
35. The equation which forms the basis of the Mollier diagram is
Correct : C. tds=dh-vdp
36. Which of the following statements is true?
Correct : D. all of the mentioned
37. Which of the following represents the latent heat of vaporization at a particular pressure.
Correct : B. hg-hf
38. At critical pressure, value of Hg-Hf is
Correct : C. zero
39. In the Mollier diagram, the constant pressure lines diverge from one another.
Correct : A. true
40. Which of the following is a property of a pure substance?
Correct : D. all of the mentioned
41. For water, as temperature increases, volume always increases?
Correct : B. false
42. Which of the following exists in a p-V diagram for water?
Correct : D. all of the mentioned
43. The isotherm passing through the critical point is called the critical isotherm.
Correct : A. true
44. The properties of water are arranged in the steam tables as functions of
Correct : C. pressure and temperature
45. The internal energy of saturated water at the triple point is
Correct : B. 0
46. The entropy of saturated water is chosen to be zero at triple point.
Correct : A. true
47. When a liquid and its vapour are in equilibrium at a certain pressure and temperature, then which of the following is required to identify the saturation state.
Correct : D. pressure or temperature
48. Saturated liquid or the saturated vapour has how many independent variables?
Correct : A. one
49. If data are required for intermediate temperatures or pressures, linear interpolation is normally accurate.
Correct : A. true
50. The superheat or degree of superheat is given by
Correct : B. difference between the temperature of superheated vapour and saturation temperature
51. When the temperature of a liquid is less than the saturation temperature at the given pressure, the liquid is called compressed liquid.
Correct : A. true
52. Which of the following statement is true?
Correct : C. both of the mentioned
53. Why is the steam not allowed to expand deep into the two phase region before it is taken to reheating?
Correct : C. to protect reheat tubes
54. Net Work output of the plant with reheat.
Correct : B. increases
55. What is the effect of decrease of reheat pressure on the quality of steam at turbine exhaust?
Correct : B. increases
56. The optimum reheat pressure for most of the power plants is how many times of the initial steam pressure?
Correct : C. 0.2-0.25
57. What is the most preferable dryness
Correct : D. 0.88
58. For pressure ratio = 1, efficiency = 0, then?
Correct : B. reheat is not used
59. At critical point, value of Vg-Vf is
Correct : C. zero
60. Above the critical point, the isotherms are continuous curves.
Correct : A. true
61. A piston –cylinder device contains 0.06m3 of saturated water vapour at 350 kPa pressure. Determine the temperature and mass of the vapour inside the cylinder.
Correct : D. 0.114 kg
62. A rigid tank contains 10 kg of water at 90°C. If 8 kg of the water is in the liquid form and the rest is in the vapour form, determine the pressure in the tank.
Correct : B. 70.183 kpa
63. A rigid tank contains 10 kg of water at 90°C. If 8 kg of the water is in the liquid form and the rest is in the vapour form, determine the volume of the tank.
Correct : D. 4.73 m3
64. An 80 litre vessel contains 4 kg of R-134a at a pressure of 160 kPa. Determine the quality.
Correct : D. 0.157
65. Determine the specific volume of R-134a at 1 MPa and 50°C, using ideal gas equation of state.
Correct : B. 0.024325 m3/kg
66. What is the unit of Heat rate?
Correct : A. kj/kw
67. Rankine cycle operating on low pressure limit of p1 and high pressure limit of p2
Correct : A. has higher thermal efficiency than the carnot cycle operating between same pressure limits
68. Rankine efficiency of a Steam Power Plant
Correct : B. improves in winter as compared to that in summer
69. Rankine cycle comprises of
Correct : B. two isentropic processes and two constant pressure processes
70. In Rankine cycle, the work output from the turbine is given by
Correct : B. change of enthalpy between inlet and outlet
71. What is the actual turbine inlet temperature in Rankine cycle?
Correct : C. 550c
72. Rankine cycle efficiency of a good Steam Power Plant may be in the range of?
Correct : B. 35 to 45%
73. A simple Rankine cycle produces 40 MW of power, 50 MW of process heat and rejects 60 MW of heat to the surroundings. What is the utilization factor of this co generation cycle neglecting the pump work?
Correct : B. 60
74. Why both reheating and regeneration is used together?
Correct : C. both of the mentioned
75. Which of the following statement is true?
Correct : D. all of the mentioned
76. Which of the following is true for an open heater?
Correct : B. a pump is required at each heater
77. Deaerator is a type of open heater.
Correct : A. true
78. Which of the following is true for a closed heater?
Correct : C. both of the mentioned
79. The efficiency gain follows the law of diminishing return with the increase in the number of heaters.
Correct : A. true
80. Which of the following statement is true?
Correct : D. all of the mentioned
81. The corrected gas equation is given by
Correct : D. (p+a/(v2))(v-b)=rt
82. Which of the following statement is true about the correction terms?
Correct : D. all of the mentioned
83. Compressibility factor Z is given by
Correct : B. pv/rt
84. For an ideal gas, Z has the value
Correct : C. 1
85. The magnitude of Z at a particular pressure and temperature indicates the extent of deviation of the gas from the ideal gas behaviour.
Correct : A. true
86. For the ideal gas equation, what assumptions are made?
Correct : C. both of the mentioned
87. When does a real gas obey the ideal gas equation closely?
Correct : B. at low pressure and high temperature
88. The real gases deviate from the ideal gas equation when the pressure increases.
Correct : A. true
89. Real gases conform more closely with the van der Waals equation of state than the ideal gas equation of state.
Correct : A. true
90. What is the pressure of H2 with compressibility 0.6, molar volume 5 liter/mole at 27oC?
Correct : A. 2.9 atm
91. 3 COMPRESSIBILITY CHART AND ITS USE
Correct : B. 304.5 k
92. What is the pressure of 80 grams of CH4 with compressibility 5, with 10 liter volume at 27oC?
Correct : D. 61.5 atm view answer
93. What is the compressibility of neon (molar mass = 20) with density 20 g/liter at 27oC and 100 atm?
Correct : C. 4
94. 90 g glucose is filled in a container at 10 atm, if the volume of container is 2 liter, what is the temperature of glucose (z = 1.5)?
Correct : B. 51.7oc
95. at 1 atm and 27oC?
Correct : A. 23.4 liter
96. 39 grams of benzene (z = 1.4) is filled in a container of volume 10 liter at 27oC, what is the pressure of container?