Answer: Remains same.
- A Increases
- B Decreases
- C Remains same
- D Depends on gas
Correct answer: C. Remains same
Explanation: In free expansion, no work done (W=0) and no heat exchange (Q=0). So delta U = 0. For ideal gas, U depends on T only, so T stays constant.
The Carnot cycle alternates two isothermal steps (heat absorbed at TH, released at TC) with two adiabatic steps (no heat exchange); the enclosed loop area equals the net work output, and η = 1−TC/TH is the maximum possible efficiency between those two temperatures.
Concept context
Laws of thermodynamics, heat engines, entropy, and gas processes.