Thermodynamics Questions and Answers – Clausius’ Theorem and the Inequality of Clausius

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This set of Thermodynamics Multiple Choice Questions & Answers (MCQs) focuses on “Clausius’ Theorem and the Inequality of Clausius”.

1. Any reversible path can be substituted by a reversible zigzag path between the same states.
a) true
b) false
View Answer

Answer: a
Explanation: It should consist of a reversible adiabatic, followed by a reversible isotherm and then by a reversible adiabatic.
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2. According to the Clausius’ theorem, the cyclic integral of ____ for a reversible cycle is zero.
a) dW/dT
b) dH/dT
c) dQ/dT
d) dE/dT
View Answer

Answer: c
Explanation: Q is the total heat supplied or heat rejected in the complete cycle.

3. Two reversible adiabatic paths can intersect each other.
a) true
b) false
View Answer

Answer: b
Explanation: If we assume they intersect, then the Kelvin-Planck statement of the second law will be violated.
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4. The efficiency of a general cycle will be _____ the efficiency of a reversible cycle.
a) equal to
b) less than
c) equal to or greater than
d) equal to or less than
View Answer

Answer: d
Explanation: The efficiency of a reversible cycle is maximum.

5. The cyclic integral of entropy is____
a) one
b) zero
c) infinity
d) cannot be determined
View Answer

Answer: b
Explanation: The cyclic integral of any property is zero and entropy is a property.
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6. Which of the following is known as the inequality of Clausius?
a) cyclic integral of dQ/T<=0
b) cyclic integral of dQ/T>=0
c) cyclic integral of dW/T<=0
d) cyclic integral of dW/T>=0
View Answer

Answer: a
Explanation: It provides the criterion for the reversibility of a cycle.

7. If the cyclic integral of dQ/T is zero then the cycle is
a) irreversible but not possible
b) irreversible but possible
c) impossible
d) reversible
View Answer

Answer: d
Explanation: This comes from the inequality of Clausius.
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8. If the cyclic integral of dQ/T is less than zero then the cycle is
a) irreversible but not possible
b) irreversible and possible
c) impossible
d) reversible
View Answer

Answer: b
Explanation: This comes from the inequality of Clausius.

9. If the cyclic integral of dQ/T is greater than zero then the cycle is
a) irreversible but not possible
b) irreversible but possible
c) impossible
d) reversible
View Answer

Answer: c
Explanation: This comes from the inequality of Clausius.
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10. If dQ is the heat supplied at T and dQ2 is the heat rejected at T2, then efficiency is given by
a) 1-(dQ2/dQ)
b) 1-(dQ/dQ2)
c) (dQ/dQ2)-1
d) (dQ2/dQ)-1
View Answer

Answer: a
Explanation: Efficiency is given by = 1-(heat reached/heat supplied).

11. A heat engine receives 6 kW from a source at 250°C and rejects heat at 30°C with W. = 0 kW. Does this satisfy the inequality of Clausius?
a) yes
b) no
c) cannot be said
d) none of the mentioned
View Answer

Answer: a
Explanation: ⌠ dQ/T = (6000/523) – (6000/303) = –8.33 kW/K < 0. [/expand] 12. A heat engine receives 6 kW from a source at 250°C and rejects heat at 30°C with W. = 6 kW. Does this satisfy the inequality of Clausius? a) yes b) no c) cannot be said d) none of the mentioned [expand title="View Answer"]Answer: b Explanation: ⌠ dQ/T = (6000/523) - (0/303) = 11.47 kW/K > 0.

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