Answer: Both B and C.
- A P1V1 - P2V2
- B (P1V1 - P2V2)/(gamma-1)
- C nCv(T1-T2)
- D Both B and C
Correct answer: D. Both B and C
Explanation: W = -delta U = nCv(T1-T2) = (P1V1-P2V2)/(gamma-1). These are equivalent. Both B and C are correct.
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.