Question

If a heat engine gives an output of 3 kw when the input is 10,000 j/s, then the thermal efficiency of the engine will be

Answer 1

Do ask if you will face any problem

Answer 2

The given “engine’s thermal efficiency” is 30%.

Given:

Output given out by the heat engine (W)=3kw

Input given to the heat engine (Q)=10000j/s

To find:

We have to find the thermal efficiency of the engine.

Solution:

We know that thermal efficiency $\eta=\frac{w}{Q}$

Thermal efficiency $=\frac{\text { work done by the heat engine}}{\text {heat supplied by the heat engine}}$

Here work done=3kw

Heat supplied=10000j/s

Hence to find the thermal efficiency substitute the values of W and Q in the above expression

We get

$\eta=\frac{3 \times 10^{3}}{10000}$

$=\frac{3000}{10000}$

=0.3  

=30%  

Therefore, the thermal efficiency becomes $30 \%$.