Question

A steam engine delivers $5.4\times {10}^{8}J$ of work per minute and services $3.6\times {10}^{9}J$ of heat per minute from its boiler. What is the efficiency of the engine? How much heat is wasted per minute?

Answer 1

Heat absorbed by the boiler(input) $=3.6\times {10}^{9}J$

Work done by the steam engine $=5.4\times {10}^{8}J$


Efficiency of the steam engine $=\frac{\text{Useful work}}{\text{Heat Input}}$
${\eta }_{SE}=\frac{5.4\times {10}^8}{3.6\times {10}^9}=0.15=15\%$

Heat energy wasted $=3.6\times {10}^9-5.4\times {10}^8$

$=3.06\times {10}^{9}Jmi{n}^{-1}$

Final Answer: $15\%,30.6\times {10}^{8}Jmi{n}^{-1}$.