Answer: 0.25 J/K.
- A 0.1 J/K
- B 0.25 J/K
- C 40 J/K
- D 400 J/K
Correct answer: B. 0.25 J/K
Explanation: delta S = Q<sub>rev</sub> / T = 100/400 = 0.25 J/K.
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.