For which combination of working temperatures of the source and sink, the efficiency of Carnot's heat engine is maximum?

Options

A. 600 K, 400 K
B. 400 K, 200 K
C. 500 K, 300 K
D. 300 K, 100 K

Answer

D

Explanation

Efficiency of Carnot's engine,
`eta =1 -(T_(2))/(T_(1)) = (T_(1)-T_(2))/(T_(1))`
where `T_(1)` and `T_(2)` be the temperatures of source and sink respectively.
In all four cases, `T_(1) - T_(2) = 200 K`. Therefore, is maximum when `T_(1)` is minimum.