An engine operating between the boiling and freezing points of water will have:
1. efficiency more than 27%
2. efficiency less than a Carnot engine operating between the same temperatures
3. efficiency equal to 27%
4. efficiency less than 27% Choose the correct answer.

Question

G1 Physics · Accepted Answer

The maximum possible efficiency is the Carnot efficiency: η꜀ = 1 - T꜀/Tₕ = 1 - 273/373 ≈ 0.268 = 26.8% A real engine must have efficiency less than the Carnot value, hence less than 27%. Therefore statements 2 and 4 are correct. Hence option C follows.

An engine operating between the boiling and freezing points of water will have: 1. efficiency more than 27% 2. efficiency less than a Carnot engine operating between the same temperatures 3. efficiency equal to 27% 4. efficiency less than 27% Choose the correct answer.