Answer: 60%.
- A 60%
- B 40%
- C 50%
- D 30%
Correct answer: A. 60%
Explanation: η = 1 - Q<sub>c</sub>/Q<sub>h</sub> = 1 - 320/800 = 0.60 = 60%.
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.