The efficiency of a Carnot's engine, working between steam point and ice point, will be :

Solution

Physics sir · 3 steps

Turn both points into kelvin first, then efficiency is just the temperature gap over the hot temperature.

1. Identify the reservoirs. The steam point is 100 °C, so the hot reservoir is T₁ = 373 K. The ice point is 0 °C, so the cold reservoir is T₂ = 273 K.

   η = 1 - T₂/T₁ = (T₁ - T₂)/T₁

2. Put in numbers. η = (373 - 273)/373 = 100/373 = 0.2681.
3. So. The efficiency is 0.2681 × 100 = 26.81%, which is option (a).

The idea to keep. Carnot efficiency only works with absolute temperatures. Convert to kelvin, then divide the temperature difference by the hot reservoir's temperature.

Answer from the NTA final answer key. Solution by PrepWiser.