Thermodynamics Questions and Answers – Reversed Heat Engine

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This set of Thermodynamics Multiple Choice Questions & Answers (MCQs) focuses on “Reversed Heat Engine”.

1. Refrigeration is the cooling of any system below its surroundings temperature.
a) true
b) false
View Answer

Answer: a
Explanation: This is what refrigeration means.
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2. Dry ice is suitable for ____ temperature refrigeration.
a) high
b) low
c) all range of
d) none of the mentioned
View Answer

Answer: b
Explanation: Dry ice when exposed to atmosphere sublimates by absorbing latent heat of sublimation.

3. A reversed heat engine
a) receives heat from a low temperature region
b) gives heat to a high temperature region
c) receives a net inflow of work
d) all of the mentioned
View Answer

Answer: d
Explanation: This is the basic working of reversed heat engine.
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4. Which of the following is a reversed heat engine cycle?
a) heat pump cycle
b) refrigeration cycle
c) both of the mentioned
d) none of the mentioned
View Answer

Answer: c
Explanation: These are the reversed heat engine cycles.

5. For a heat pump, coefficient of performance is given by (Q1 is the heat taken from low temperature region and Q2 is the heat given to high temperature region)
a) Q1/(Q1-Q2)
b) Q2/(Q1-Q2)
c) 1- (Q1/Q2)
d) 1- (Q2/Q1)
View Answer

Answer: a
Explanation: For a heat pump, COP = Q1/W = Q1/(Q1-Q2).
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6. For a regenerator, coefficient of performance is given by (Q1 is the heat taken from low temperature region and Q2 is the heat given to high temperature region)
a) Q1/(Q1-Q2)
b) Q2/(Q1-Q2)
c) 1- (Q1/Q2)
d) 1- (Q2/Q1)
View Answer

Answer: b
Explanation: For a heat pump, COP = Q2/W = Q2/(Q1-Q2).

7. The working fluid in a refrigeration cycle is known as refrigerant.
a) true
b) false
View Answer

Answer: a
Explanation: A refrigerant is referred particularly to a refrigeration cycle.
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8. Which of the following happens in a reversed Carnot cycle?
a) the refrigerant is compressed reversibly and adiabatically
b) it is condensed reversibly
c) it expands reversibly and adiabatically
d) all of the mentioned
View Answer

Answer: d
Explanation: These processes take place in a reversed Carnot cycle.

9. For a heat pump, coefficient of performance is given by (T1 is the temperature of heat rejection and T2 is the temperature of heat absorption)
a) T1/(T1-T2)
b) T2/(T1-T2)
c) 1- (T1/T2)
d) 1- (T2/T1)
View Answer

Answer: a
Explanation: For a heat pump, COP = Q1/W = T1/(T1-T2).
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10. For a regenerator, coefficient of performance is given by (T1 is the temperature of heat rejection and T2 is the temperature of heat absorption)
a) T1/(T1-T2)
b) T2/(T1-T2)
c) 1- (T1/T2)
d) 1- (T2/T1)
View Answer

Answer: b
Explanation: For a heat pump, COP = Q2/W = T2/(T1-T2).

11. For the same T1 and T2, COP increases with ____ in temperature difference.
a) increase
b) decrease
c) no change
d) none of the mentioned
View Answer

Answer: b
Explanation: This means, closer the temperatures T1 and T2, the higher is the COP.

Sanfoundry Global Education & Learning Series – Thermodynamics.
To practice all areas of Thermodynamics, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer & SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage, Advanced C Programming, SAN Storage Technologies, SCSI Internals & Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him @ LinkedIn | Youtube | Instagram | Facebook | Twitter