Question

An inventor claims to have invented a heat engine that operates between the temperatures of 627°C and 27°C with a thermal efficiency of 70%. Comment on the validity of this claim.

Answer 1

Answer Explanation:

the efficiency of the the engine is given by=1-
`(T_2)/(T_1)`

where T₂= lower temperature

T₁= Higher temperature

we have given efficiency =70%

lower temperature T₂=27°C=273+27=300K

higher temperature T₁=627°C=273+627=900K

efficiency=1-
`(T_2)/(T_1)`

=1-
`(300)/(900)`

=1-0.3333

=0.6666

=66%

66% is less than 70% so so inventor claim is wrong