MCQOPTIONS
Saved Bookmarks
MCQOPTIONS
This section includes 430 Mcqs, each offering curated multiple-choice questions to sharpen your Thermodynamics knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
Which of the following is an example of high grade energy? |
| A. | mechanical work |
| B. | electrical energy |
| C. | water power and wind power |
| D. | water power and wind power |
| Answer» E. | |
| 52. |
Which of the following is mostly neglected while doing calculations for finding maximum work? |
| A. | KE |
| B. | PE |
| C. | both of the mentioned |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 53. |
Which of the following is true for a closed system? |
| A. | mass entering = mass leaving |
| B. | mass does not enter or leave the system |
| C. | mass entering can be more or less than the mass leaving |
| D. | none of the mentioned |
| Answer» C. mass entering can be more or less than the mass leaving | |
| 54. |
Which of the following is true for a steady flow system? |
| A. | mass entering = mass leaving |
| B. | mass does not enter or leave the system |
| C. | mass entering can be more or less than the mass leaving |
| D. | none of the mentioned |
| Answer» B. mass does not enter or leave the system | |
| 55. |
Work done in all reversible processes is equal |
| A. | true |
| B. | false |
| Answer» B. false | |
| 56. |
For a process from state 1 to state 2, heat transfer in an irreversible process is given by |
| A. | Q for irreversible=(To)*(S1-S2) |
| B. | Q for irreversible>(To)*(S1-S2) |
| C. | Q for irreversible<(To)*(S1-S2) |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 57. |
In an open system, for maximum work, the process must be entirely |
| A. | irreversible |
| B. | reversible |
| C. | adiabatic |
| D. | none of the mentioned |
| Answer» C. adiabatic | |
| 58. |
For a process from state 1 to state 2, heat transfer in a reversible process is given by |
| A. | Q for reversible=(To)*(S1-S2) |
| B. | Q for reversible=(To)*(S2-S1) |
| C. | Q for reversible=(To)/(S1-S2) |
| D. | Q for reversible=(To)/(S2-S1) |
| Answer» C. Q for reversible=(To)/(S1-S2) | |
| 59. |
Only those processes are possible in nature which would give an entropy ____ for the system and the surroundings together. |
| A. | decrease |
| B. | increase |
| C. | remains same |
| D. | none of the mentioned |
| Answer» C. remains same | |
| 60. |
A piston-cylinder device initially contains air at 150 kPa and 27 C. At this state, the volume is 400 litre. The mass of the piston is such that a 350 kPa pressure is required to move it. The air is now heated until its volume has doubled. Determine the total heat transferred to the air. |
| A. | 747 kJ |
| B. | 757 kJ |
| C. | 767 kJ |
| D. | 777 kJ |
| Answer» D. 777 kJ | |
| 61. |
The equation W= vdp holds good for |
| A. | work-producing machine like an engine or turbine |
| B. | work-absorbing machine like a pump or a compressor |
| C. | both of the mentioned |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 62. |
The equation dQ=dE+dW holds good for |
| A. | any process, reversible or irreversible |
| B. | only reversible process |
| C. | only irreversible process |
| D. | none of the mentioned |
| Answer» B. only reversible process | |
| 63. |
The equation TdS=dU+pdV is obtained from which law? |
| A. | first law |
| B. | second law |
| C. | both of the mentioned |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 64. |
Which of the following equation is true? |
| A. | TdS=dH+Vdp |
| B. | TdS=dH-Vdp |
| C. | TdS=-dH-Vdp |
| D. | TdS=-dH+Vdp |
| Answer» C. TdS=-dH-Vdp | |
| 65. |
When W=1, we get S=0 which can occur only at T=0K. This is the Nernst-Simon statement of third law of thermodynamics. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 66. |
According to the Boltzmann, |
| A. | he introduced the thermodynamic probability with each state |
| B. | increase in entropy implies that the system proceeds by itself towards a state of higher thermodynamic probability |
| C. | an irreversible process goes on happening until the most probable is achieved |
| D. | all of the mentioned |
| Answer» E. | |
| 67. |
In the reversible adiabatic expansion of a gas the increase in disorder due to an increase in volume is compensated by the decrease in disorder due to a decrease in temperature. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 68. |
When does the entropy of a system become zero? |
| A. | W=0 |
| B. | W=1 |
| C. | W=-1 |
| D. | none of the mentioned |
| Answer» C. W=-1 | |
| 69. |
The equation dQ=TdS is true only for a reversible process. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 70. |
Which of the following factor affects the heat of reaction based on Kirchhoff equation? |
| A. | molecularity |
| B. | temperature |
| C. | pressure |
| D. | volume |
| Answer» C. pressure | |
| 71. |
Chemical dissociation is |
| A. | exothermic |
| B. | reversible |
| C. | endothermic |
| D. | reversible and endothermic |
| Answer» E. | |
| 72. |
What is the ratio of Cp/Cv for gas if the pressure of the gas is proportional to the cube of its temperature and the process is an adiabatic process? |
| A. | 2 |
| B. | 3/2 |
| C. | 4/3 |
| D. | 5/3 |
| Answer» C. 4/3 | |
| 73. |
Which of the following processes is used to do maximum work done on the ideal gas that is compressed to half of its initial volume? |
| A. | isothermal |
| B. | isochoric |
| C. | isobaric |
| D. | adiabatic |
| Answer» E. | |
| 74. |
The entropy increase due to internal irreversibility is also called entropy production or entropy generation. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 75. |
Entropy increase dS of the system can be expressed as |
| A. | dS=dS(due to external heat interaction)-dS(due to internal irreversibility) |
| B. | dS=dS(due to external heat interaction)+dS(due to internal irreversibility) |
| C. | dS=-dS(due to external heat interaction)-dS(due to internal irreversibility) |
| D. | dS=-dS(due to external heat interaction)+dS(due to internal irreversibility) |
| Answer» C. dS=-dS(due to external heat interaction)-dS(due to internal irreversibility) | |
| 76. |
The entropy of any closed system can increase in which if the following way? |
| A. | by heat interaction in which there is entropy transfer |
| B. | dissipative effects or internal irreversibilities |
| C. | both of the mentioned |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 77. |
Argon in a light bulb is at 90 kPa and heated from 20 C to 60 C with electrical power. Find the total entropy generation per unit mass of argon. |
| A. | 0.01 kJ/kg K |
| B. | 0.02 kJ/kg K |
| C. | 0.03 kJ/kg K |
| D. | 0.04 kJ/kg K |
| Answer» E. | |
| 78. |
Oxygen gas in a piston cylinder at 300 K, 100 kPa with volume 0.1m^3 is compressed in a reversible adiabatic process to a final temperature of 700 K. Find the final pressure and volume. |
| A. | 2015 kPa, 0.0116 m3 |
| B. | 3015 kPa, 0.0216 m3 |
| C. | 1015 kPa, 0.0416 m3 |
| D. | 4015 kPa, 0.0216 m3 |
| Answer» B. 3015 kPa, 0.0216 m3 | |
| 79. |
A pan contains 5 L of engine oil at 20 C, 100 kPa. Now 2 L of hot 100 C oil is mixed into the pan. Find the entropy generation. |
| A. | 0.0728 kJ/K |
| B. | 0.0828 kJ/K |
| C. | 0.0928 kJ/K |
| D. | 0.1028 kJ/K |
| Answer» B. 0.0828 kJ/K | |
| 80. |
A 4 L jug of milk at 25 C is placed in refrigerator where it is cooled down to a temperature of 5 C. Assuming the milk has the property of liquid water, find the entropy generated in the cooling process. |
| A. | 0.0215 kJ/K |
| B. | 0.0315 kJ/K |
| C. | 0.0415 kJ/K |
| D. | 0.0515 kJ/K |
| Answer» D. 0.0515 kJ/K | |
| 81. |
1kg of ammonia is contained in a piston/cylinder, as saturated liquid at 20 C. Heat is added at 100 C until a final condition of 70 C, 800 kPa is reached. Assuming the process is reversible, find the entropy generation. |
| A. | 1.007 kJ/K |
| B. | 1.107 kJ/K |
| C. | 1.207 kJ/K |
| D. | 1.307 kJ/K |
| Answer» E. | |
| 82. |
A piston/cylinder contains 1 kg water at 20 C, 150 kPa. The pressure is linear in volume. Heat is added from 600 C source until the water is at 1 MPa, 500 C. Find the total change in entropy. |
| A. | 1.751 kJ/K |
| B. | |
| C. | C. |
| D. | D. |
| Answer» D. D. | |
| 83. |
The equation TdS=dH-Vdp |
| A. | relates only the properties of a system |
| B. | there is no path function term in the equation |
| C. | the equation holds good for any process |
| D. | all of the mentioned |
| Answer» E. | |
| 84. |
The entropy change of a system between two identifiable equilibrium state is ___ when the intervening process is reversible or change of state is irreversible. |
| A. | different |
| B. | same |
| C. | depends on the process |
| D. | none of the mentioned |
| Answer» C. depends on the process | |
| 85. |
The rate at which entropy is transferred out must ____ the rate at which entropy enters the control volume. |
| A. | be less than |
| B. | equal to |
| C. | exceed |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 86. |
Mass and energy are conserved quantities, but entropy is generally not conserved. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 87. |
The rate of entropy increase of the control volume ____ or ____ the net rate of entropy transfer to it. |
| A. | exceeds or is less than |
| B. | exceeds, is equal to |
| C. | is less than, or equal to |
| D. | none of the mentioned |
| Answer» C. is less than, or equal to | |
| 88. |
In an open system, there is a transfer of which of the following quantity? |
| A. | mass |
| B. | energy |
| C. | entropy |
| D. | all of the mentioned |
| Answer» E. | |
| 89. |
If the path A causes more entropy generation than path B, then |
| A. | path A is more irreversible than path B |
| B. | path A involves more lost work |
| C. | both of the mentioned |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 90. |
Any thermodynamic process is accompanied by entropy generation |
| A. | true |
| B. | false |
| Answer» B. false | |
| 91. |
The amount of entropy generation is given by |
| A. | S2+S1+ (dQ/T) |
| B. | S2-S1+ (dQ/T) |
| C. | S2-S1- (dQ/T) |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 92. |
Lost work is given by |
| A. | pdV-dW |
| B. | pdV+dW |
| C. | -pdV-dW |
| D. | pdV*dW |
| Answer» B. pdV+dW | |
| 93. |
A machine that continuously creates its own energy is known as |
| A. | Perpetual motion machine of second kind |
| B. | Self-propelled machine |
| C. | 100% efficient machine |
| D. | Perpetual motion machine of first kind |
| E. | Reversible machine |
| Answer» E. Reversible machine | |
| 94. |
The process in which no heat enters or leaves the system is called |
| A. | Isobaric |
| B. | Isothermal |
| C. | Isentropic |
| D. | Isochoric |
| E. | None of the above |
| Answer» D. Isochoric | |
| 95. |
Balanced draft incorporates |
| A. | Forced draft |
| B. | Induced draft |
| C. | Forced and induced draft |
| D. | Chimney draft only |
| E. | None of the above |
| Answer» D. Chimney draft only | |
| 96. |
The external work donw is zero all the following cases EXCEPT |
| A. | Pulsejet |
| B. | Constant volume |
| C. | Isothermal |
| D. | Free expansiton |
| E. | Throttling |
| Answer» D. Free expansiton | |
| 97. |
As we go up in air the temperature of air decreases because |
| A. | Pulsejet |
| B. | winds help in heat transfer by convection |
| C. | of low pressure of air |
| D. | oxygen content of air decreases sharply |
| E. | heating effect due to infra red radiations from the surface of the earth is reduced |
| Answer» F. | |
| 98. |
When a direct current is passed through a junction of two dissimilar metals, the junction becomes either cold or hot. The phenomenon is known as |
| A. | Faraday's law |
| B. | Peltier's effect |
| C. | Thompson effect |
| D. | Maxwell's effect |
| E. | Seeback's effect |
| Answer» C. Thompson effect | |
| 99. |
Entropy of the universe tends to |
| A. | Approximately zero |
| B. | A minimum |
| C. | A maximum |
| D. | No particular value as it remains constant |
| E. | Zero |
| Answer» D. No particular value as it remains constant | |
| 100. |
Second law of theromodynamics defines |
| A. | Heat |
| B. | Entropy |
| C. | Work |
| D. | Internal energy |
| E. | Enthalpy |
| Answer» C. Work | |