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-$\frac{T_2}{T_1}$

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-$\frac{T_2}{T_1}$

                =1-$\frac{300}{900}$

                 =1-0.3333

                 =0.6666

                 =66%

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