Answer: Remains constant.
- A Increases
- B Decreases
- C Remains constant
- D Becomes zero
Correct answer: C. Remains constant
Explanation: Reversible process: entropy of universe remains constant (delta S<sub>universe</sub> = 0). Irreversible processes increase it.
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.