Answer: Temperature scale.
- A Entropy
- B Temperature scale
- C Conservation of energy
- D Heat engine efficiency
Correct answer: B. Temperature scale
Explanation: Zeroth law: if A is in equilibrium with B, and B with C, then A and C are in equilibrium. This defines temperature.
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.