The correct answer to the question is 33.3 % i.e the efficiency of the engine is 33.3 %.
CALCULATION:
The steam enters a turbine at 600 K.
Hence, the temperature of the source T = 600 K.
The steam is exhausted at a temperature 400 K.
Hence, the temperature of the sink T' = 400 K
We are asked to calculate the efficiency of the engine.
The efficiency of a heat engine whose source is at temperature T K and sink at T' is calculated as -
efficiency \(\eta\ =\ 1-\frac{T'}{T}\)
\(=\ 1-\frac{400\ K}{600\ K}\)
\(=\ 1-\frac{2}{3}\)
\(=\ \frac{1}{3}\)
\(=\ 33.3\%\) [ans]
Hence, the efficiency of the engine is 33.3 %.
