In a cyclic process, after one complete cycle the internal energy of the system
Correct answer: C. returns to its original value, so the net heat supplied equals the net work done
- A. increases by the work done
- B. decreases by the heat rejected
- C. returns to its original value, so the net heat supplied equals the net work done
- D. becomes zero
Explanation
Internal energy is a function of state, so returning to the same pressure, volume and temperature restores it exactly, and the first law then reduces to net heat equals net work. That work is the area enclosed by the loop on a pressure volume diagram. Every heat engine relies on this, since it must return to its starting state to run continuously.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? support@testustad.com
About First Law of Thermodynamics
The first law relates heat supplied, work done and the change in internal energy through energy conservation. Problems use sign conventions and apply the law to isothermal, adiabatic, isobaric and isochoric processes. Internal energy is a state function, while heat and work depend on the path followed.
Practise Thermodynamics
714 free Thermodynamics MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Physics questions like this
Physics is on 16 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More First Law of Thermodynamics questions
A refrigerator works by
A Carnot engine operates between reservoirs at 600 K and 300 K. Its maximum possible efficiency is
The second law of thermodynamics implies that
Which process involves no heat exchange with the surroundings?
In an isochoric process, carried out at constant volume, the work done by the gas is
Entropy is best described as a measure of