1. For getting TdS equations, we assume entropy to be a function of T and V and also of T and p.
Correct : A. true
2. During phase transitions like vaporization, melting and sublimation
Correct : C. both of the mentioned
3. Which of the following requirement is satisfied by a phase change of the first order?
Correct : C. both of the mentioned
4. The vapour pressure p in kPa at
Correct : D. p = 101.325 exp (88/r)(1-tb/t)
5. The vapour pressure curve is of the form ln(p) = A + B/T + C*lnT + DT.
Correct : A. true
6. According to Trouton’s rule, the ratio of latent heat of vaporization to the boiling point at 1.013 bar is
Correct : B. 88 kj/kgmol k
7. Estimate the freezing temperature of liquid water at a pressure of 30 MPa.
Correct : A. -2.2°c
8. The expression nRT/V is called the partial pressure of a gas.
Correct : A. true
9. The gas constant of the mixture is the of the gas constants of the components.
Correct : B. weighted mean
10. A quantity called partial volume of a component of mixture is used.
Correct : A. true
11. When gases which are at equal pressure and temperature are mixed adiabatically without work, then
Correct : A. internal energy of the gaseous system remains constant
12. The fact that internal energy of a mixture is equal to the sum of the partial internal energies of the gases can also be applied to properties like H,Cv,Cp,S,F, and G.
Correct : A. true
13. Which of the following statement is true?
Correct : D. all of the mentioned
14. In sensible heating or cooling,
Correct : A. work done remains constant
15. Cooling and dehumidification of air is done in summer air conditioning.
Correct : A. true
16. Heating and humidification is done in
Correct : B. winter air conditioning
17. Which of the following is an absorbent?
Correct : C. both of the mentioned
18. When air passes through silica gel,
Correct : D. all of the mentioned
19. In adiabatic evaporative cooling, heat transfer between chamber and surroundings is
Correct : A. zero
20. The cooling tower uses the phenomenon of evaporative cooling to cool warm water above the dbt of air.
Correct : B. false
21. Cooling towers are rated in terms of
Correct : C. both of the mentioned
22. Dry air consists of
Correct : D. all of the mentioned
23. Complete dry air exists in nature.
Correct : B. false
24. Which of the following is true?(here pa=partial pressure of dry air, pw=partial pressure of water vapour, p=atmospheric pressure)
Correct : C. p=pw + pa
25. In a mixture of dry air and water vapour,
Correct : C. both of the mentioned
26. When pw is very small,
Correct : D. all of the mentioned
27. Relative humidity is defined as
Correct : B. pw / (saturation pressure of pure water)
28. For saturated air, relative humidity is 0%.
Correct : B. false
29. If water is injected into a container with has unsaturated air,
Correct : A. water will evaporate
30. Humidity ratio is given by the ratio of
Correct : C. water vapour mass per unit mass of dry air
31. Which of the following statement is true?
Correct : D. all of the mentioned
32. The wet bulb temperature is the temperature recorded by moistened bulb.
Correct : A. lowest
33. Air can be cooled and dehumidified by
Correct : D. all of the mentioned
34. When two equilibrium states are infinitesimally near,
Correct : A. dq/t=ds
35. The greater the temperature, the is the vapour pressure.
Correct : B. higher
36. It is necessary to have a temperature difference to obtain work of any cycle.
Correct : A. true
37. The absolute thermodynamic temperature scale is also known as
Correct : B. kelvin scale
38. In defining the temperature scale, the standard reference point is taken as
Correct : C. triple point of water
39. When the heat transferred isothermally between the given decreases, the temperature
Correct : D. adiabatics, decreases
40. If a system undergoes a reversible isothermal process without transfer of heat, the temperature at which this process takes place is called
Correct : A. absolute zero
41. A definite zero point on the absolute temperature scale but this point be reached violation of the second law.
Correct : B. exists, cannot, without
42. Which law is stated here, “It is impossible to reduce any system to the absolute zero of temperature in a finite number of operations.
Correct : C. third law of thermodynamics
43. The statement of third law is also called the Fowler-Guggenheim statement of the third law.
Correct : A. true
44. The Kelvin temperature is numerically equal to the and may be measured by means of a
Correct : B. ideal gas temperature, gas thermometer
45. During a fluid flow, the temperature is developed due to
Correct : C. translational kinetic energy
46. The equation for the average kinetic energy is
Correct : B. 1.5 kt
47. Entropy occurs due to
Correct : A. change in macroscopic variables
48. Efficiency of a heat engine is defined as
Correct : C. net work output / total heat input
49. A TER which transfers heat to system is called and one which receives heat is called
Correct : A. source, sink
50. A reversible cycle has following processes.
Correct : C. 2 isothermal and 2 adiabatic processes
51. 2 STATEMENTS OF SECOND LAW AND ITS COROLLARIES. CARNOT CYCLE REVERSED CARNOT CYCLE, PERFORMANCE. CLAUSIUS INEQUALITY.
Correct : B. low, high, receives
52. According to Carnot’s theorem, all heat engines operating between a given constant temperature source and sink, none has a higher efficiency than a reversible engine.
Correct : A. true
53. The efficiency of all reversible heat engines operating between the same heat reservoirs is
Correct : D. all of the mentioned
54. For a reversible heat pump, COP is given by
Correct : B. t1/(t1-t2)
55. The entropy of an isolated system can never
Correct : B. decrease
56. According to entropy principle, the entropy of an isolated system can never decrease and remains constant only when the process is reversible.
Correct : A. true
57. Entropy may decrease locally at some region within the isolated system. How can this statement be justified?
Correct : C. it must be compensated by a greater increase of entropy somewhere within the system.
58. The final temperatures of two bodies, initially at T1 and T2 can range from
Correct : B. (t1+t2)/2 to sqrt(t1*t2)
59. The part of available for conversion is referred to
Correct : B. low grade energy, available energy
60. The obtainable from a certain heat input in a cyclic heat engine is called
Correct : B. maximum work output, available energy
61. 4 APPLICATIONS OF II LAW. HIGH AND LOW GRADE ENERGY.
Correct : A. true
62. The available energy is known as and the unavailable energy is known as
Correct : B. exergy, energy
63. Whenever heat is transferred through a finite temperature difference, there is always a decrease in the availability of energy so transferred.
Correct : A. true
64. Any thermodynamic process is accompanied by entropy generation.
Correct : A. true
65. The rate of entropy increase of the control volume or the net rate of entropy transfer to it.
Correct : B. exceeds, is equal to
66. The rate at which entropy is transferred out must the rate at which entropy enters the control volume.
Correct : C. exceed
67. The first law efficiency is defined as the ratio of the output energy to the input energy.
Correct : A. true
68. With the concept of exergy available, which of the following is possible?
Correct : C. both of the mentioned
69. If work is involved, Amin= and if heat is involved, Amin=
Correct : B. w, q(1-to/t)
70. If solar energy Qr is available at a reservoir storage temperature of Tr and if quantity of heat Qa is transferred by the solar collector at temperature Ta, then which of the following is true?
Correct : D. all of the mentioned
71. For proper utilization of exergy, it is desirable to make first law efficiency and the source and use temperatures should
Correct : B. as close to unity, match
72. The slopes of sublimation and vaporization curves for all substances are
Correct : B. positive
73. When does a vapour become superheated?
Correct : B. when the temperature of vapour is more than the saturation temperature at given pressure
74. The properties of liquid with pressure.
Correct : C. vary little
75. What is the effect of reheat pressure on mean temperature of heat addition Tml?
Correct : A. reheat pressure is directly proportional to tml
76. Which of the following problems are posed by increasing the number of reheats?
Correct : A. cost & fabrication problems arise
77. What is the most preferable dryness fraction of the exhaust steam?
Correct : D. 0.88
78. Which of the following represents the specific volume during phase transition.
Correct : B. vg-vf
79. An 80 litre vessel contains 4 kg of R-134a at a pressure of 160 kPa. Determine the volume occupied by the vapour phase.
Correct : A. 0.0775 m3
80. Rankine cycle comprises of
Correct : B. two isentropic processes and two constant pressure processes
81. In Rankine cycle, the work output from the turbine is given by
Correct : B. change of enthalpy between inlet and outlet
82. Which of the following contributes to the improvement of efficiency of Rankine cycle in a Thermal Power Plant?
Correct : D. all of the mentioned
83. A simple Rankine cycle operates the Boiler at 3 MPa with an outlet temperature of 350°C and the Condenser at 50 kPa. Assuming ideal operation and processes, what is the thermal efficiency of this cycle?
Correct : C. 27.7
84. How many types of feedwater heaters are present?
Correct : B. two
85. The temperature of feedwater leaving a heater is the saturation temperature at steam extraction pressure.
Correct : A. less than
86. The following also gave two-constant equations of state.
Correct : D. all of the mentioned
87. Which of the following is true about compressibility of real gases?
Correct : D. both z < 1 and z > 1 view answer
88. 1 mole of cyclohexane (z = 1.2) is filled in a container at 27oC and 4 atm, what is the volume of container?
Correct : D. 7.4 liter view answer
89. If a relation exists among variables x,y,z then z may be expressed as a function of x and y as, dz=Mdx+Ndy .
Correct : A. true
90. A pure substance which exists in a single phase has independent variables.
Correct : C. two
91. Which of the following is not a Maxwell equation?
Correct : B. (∂t/∂p) = -(∂v/∂s)
92. The Clausius-Clapeyron equation is given by
Correct : B. dp/dt = l / t(vf-vi)
93. Water on melting and has the fusion curve with a slope.
Correct : A. contracts, negative
94. At the triple point, l(sublimation) = l(vaporization) – l(fusion).
Correct : B. false
95. The slope of sublimation curve is the slope of the vaporization curve at triple point.
Correct : C. greater than
96. An application requires R-12 at −140°C. The triple-point temperature is −157°C. Find the pressure of the saturated vapour at the required condition.
Correct : B. 0.0098 kpa
97. The expression which represents the pressure exerted by a gas is
Correct : B. nrt/v
98. Which of the following relation is correct?
Correct : D. all of the mentioned
99. The total entropy of a mixture of gases is the of the partial entropies.
Correct : C. sum
100. When humidity ratio of air air is said to be dehumidified.