Question

In each cycle, a heat engine an input of 1940 J of heat and exhausts 1480 J of heat. What is the thermal efficiency?

Answer 1

0.237 (23.7 %)

Step-by-step explanation:

The thermal efficiency of an engine is given by:

`\eta=(W)/(Q_(in))`

where

W is the useful work output of the engine

`Q_(in)` is the heat in input

Here we have:

`Q_(in)=1940 J`

and the work done is the total heat in input minus the heat exhausted:

`W=1940 J - 1480 J=460 J`

So, the efficiency is

`\eta=(460 J)/(1940 J)=0.237` (23.7 %)