Question

A heat engine operating between 100°C and 700°C has an efficiency equal to 40% of the maximum the oretical efficiency. How much energy does this engine extract from the hot reservoir in order to do 500 J of mechanical work?

Answer 1

Explanation:

Correct option is

A

20%

Maximum efficiency is for engines.

For engines, we have

T

1

=25+273=298K

T

2

=100+273=373K

η=

T

2

T

2

−T

1

η=

373

373−298

=[

373

75

]

η =0.20

Hence, 20%.

So, option A is correct.