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 [tex]\eta\ =\ 1-\frac{T'}{T}[/tex]
[tex]=\ 1-\frac{400\ K}{600\ K}[/tex]
[tex]=\ 1-\frac{2}{3}[/tex]
[tex]=\ \frac{1}{3}[/tex]
[tex]=\ 33.3\%[/tex] [ans]
Hence, the efficiency of the engine is 33.3 %.
