Question

A steam engine delivers 5.4×108 J of work per minute and services 3.6 × 109 J of heat per minute from its boiler. What is the efficiency of the engine? How much heat is wasted per minute?

Answer 1

Concept :-
efficiency of a heat engine = work done per cycle / total heat given per cycle × 100 %

solution :- given,
work done ( W) = 5.4 × 10^8 J/min
Total heat energy taken from the boiler ( Q ) = 3.6 × 10^9 J/min

Now,
efficiency = work done /heat × 100
= 5.4 × 10^8/3.6 × 10^9 × 100
= 15 %

Heat wasted per minute = Q - W
= 3.6 × 10^9 - 5.4 × 10^8
= 30.6 × 10^8 J/min