Answer: nRT ln(V 2 /V 1 ).
- A nRT ln(V<sub>2</sub>/V<sub>1</sub>)
- B nRT(V<sub>2</sub>-V<sub>1</sub>)
- C nRT(V<sub>2</sub>/V<sub>1</sub> - 1)
- D nR delta T
Correct answer: A. nRT ln(V<sub>2</sub>/V<sub>1</sub>)
Explanation: W = nRT ln(V<sub>2</sub>/V<sub>1</sub>) for isothermal expansion of ideal gas.
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.