# Thermodynamics 3

Mechanical Engineering MCQ Question Papers: DRDO, ISRO, Interview

Subject:  Thermodynamics 3

Part 3: List for questions and answers of Thermodynamics 3

Q1. The degree of disorder of a mixture of two gases
a) Is always less than the degrees of disorder of individual gases
b) Is always greater than the degrees of disorder of individual gases
c) Is always equals the degrees of disorder of individual gases
d) None of the above

Q2. What is the relation between thermodynamic probability (W) and entropy?
a) Thermodynamic probability increases with entropy
b) Thermodynamic probability decreases with entropy
c) Thermodynamic probability does not change with change in with entropy
d) None of the above

Q3. At the most probable state of a system the entropy of the system is
a) Minimum
b) Maximum
c) Constant
d) None of the above

Q4. If the two parts A and B in a system are considered to be in equilibrium and having thermodynamic probabilities WA and WB, what will be the thermodynamic probability of the system?
a) W = WA . WB
b) W = WA + WB
c) W = (WA + WB) / 2
d) W = √(WA – WB)

Q5. At the state of perfect order (W = 1) of pure crystalline substance, how is the zero entropy defined?
a) Entropy at 0 °C temperature
b) Zentropy at absolute zero temperature
c) Entropy at the freezing point of the substance
d) None of the above

Q6. What is the reason behind the fact that the absolute zero entropy value is not attainable?
a) Because absolute zero temperature is not attainable in finite number of operations
b) Because theoretically absolute zero temperature has negative value of entropy and it is not possible
c) Both a. And b
d) None of the above

Q7. What is the entropy chosen at the triple point of water?
a) Zero
b) Less than zero
c) More than zero
d) None of the above

Q8. What is the effect on quality of the energy when it is conserved?
a) The quality of the energy increases while conserving its quantity
b) The quality of the energy decreases while conserving its quantity
c) The quality of the energy remains same while conserving its quantity
d) None of the above

Q9. Which analysis is required making energy conversion or energy conveying system more efficient?
a) First law or energy analysis
b) Second law or energy analysis
c) Both a. And b
d) None of the above

Q10. What is the relation between the pressure change (dp) and volume change (dv), for all the real processes in nature containing pressure change (dp) as well as volume change (dv)?
a) Dp/dv = 0
b) Dp/dv is greater than 0
c) Dp/dv is less than 0
d) All the above options are possible

Q11. What is the dead state of the system?
a) The state at which system is in pressure and temperature equilibrium with the
surroundings
b) The state at which system is in chemical equilibrium with the surroundings
c) The state at which system must have zero velocity and minimum potential energy
d) All of the above

Q12. What is the energy of a system when it is at dead state?
a) Zero
b) Less than zero
c) More than zero
d) Cannot say

Q13. What is available energy (A. E.)
a) Energy supplied to a cyclic heat engine
b) Maximum energy utilized to produce maximum work from a certain heat supplied to
a cyclic heat engine
c) Minimum heat energy rejected to sink by second law
d) Maximum heat energy rejected to sink by second law

Q14. What is unavailable energy (U. E.)
a) Energy supplied to a cyclic heat engine
b) Maximum energy utilized to produce maximum work from a certain heat supplied to a cyclic heat engine
c) Minimum heat energy rejected to sink by second law
d) Maximum heat energy rejected to sink by second law

Q15. What is the effect on energy output of a process, when heat is transferred through a finite temperature difference?
a) Energy output increases
b) Energy output decreases
c) Energy output remains same
d) None of the above

Q16. As the temperature difference between system and surroundings decreases the quality of the energy which is being transferred
a) Increases
b) Decreases
c) Remains same
d) None of the above

Q17. Which concept provides the useful measure of quality of energy?
a) Entropy
b) Energy
c) Energy
d) None of the above

Q18. Which law of thermodynamics expresses that the energy is always conserved quantity wise?
a) First law
b) Second law
c) Third law
d) None of the above

Q19. The law of degradation of energy states that
a) The energy is always conserved quantity wise
b) The energy is always conserved quality wise
c) The energy is always degraded quantity wise
d) The energy is always degraded quality wise

Q20. Two reversible processes undergone by a closed system between same two end states
a) Produce different amounts of work
b) Produce same amount of work if two systems are exchanging energy between
themselves
c) Produce same amount of work if two systems are exchanging energy with the
surroundings
d) None of the above

Part 3: List for questions and answers of Thermodynamics