Correct Answer - Option 3 : 0.5
Concept:
The second law efficiency of an engine is given by:
\(\eta_{II}=\frac{W_{actual}}{W_{maximum}}\)
where, Wactual = Actual work produced by the engine, Wmaximum = Maximum work an engine can produce
A reversible engine produced the maximum work.
Explanation:
Given:
Wactual = 20 kW, Wmaximum = 40 kW
\(\eta_{II}=\frac{20}{40}\)
\(\eta_{II}=\frac{1}{2}\)
\(\eta_{II}=0.5\)
Hence the second law efficiency of the heat engine is 0.5