The maximum theoretical efficiency of a Carnot engine operating between reservoirs at the steam point and at room temperature is about:
A) 10%
B) 20%
C) 50%
D) 80%
E) 99%

Question

Quizplus · Accepted Answer

The maximum theoretical efficiency of a Carnot engine is given by 1 - (Tc/Th), where Tc is the cold reservoir temperature and Th is the hot reservoir temperature, both in Kelvin. The steam point is 100°C (373K) and room temperature is about 20°C (293K). Thus, the efficiency is 1 - (293/373) ≈ 0.21 or 21%, which is closest to 20%.

The Maximum Theoretical Efficiency of a Carnot Engine Operating Between