Answer: 750 K.
- A 500 K
- B 600 K
- C 750 K
- D 900 K
Correct answer: C. 750 K
Explanation: eta = 1 - Tcold/Thot. 0.6 = 1 - 300/Thot. 300/Thot = 0.4. Thot = 750 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.