Question

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

Answer 1

Given, the work delivered by the steam engine per minute is 5.4× 10 8  J and heat energy accepted by boiler per minute is 3.6× 10 9  J.

Let W be the work done by engine and Q be the heat energy accepted by the boiler, so

Efficiency= W Q

Substitute the values in the above expression.

Efficiency= 5.4× 10 8 3.6× 10 9 =0.15 or 15%

Hence, the efficiency of the engine is 15%.

Let H be the amount of heat wasted, so

H=W−Q

Substitute the values in the above expression,

H=3.6× 10 9 −5.4× 10 8 =3.1× 10 9  J

Therefore, the amount of heat wasted per minute is 3.1× 10 9  J.