A Carnot engine whose heat sink is at 27 ° C has an efficieny of 40 % . By how much should its source temperature be changed so as to increase its efficiency to 60 % ?

Step-by-step solution

Efficiency of the engine, η = 1 - T sink T source Given, Sink temperature, T sink = 27 °   C = 300   K ⇒ 0 . 4 = 1 - 300 T source ⇒ 300 T source = 0 . 6 ⇒ T source = 500   K For η = 60 % , ⇒ 0 . 6 = 1 - 300 T source ⇒ 300 T source = 0 . 4 ⇒ T source = 750   K Change in source temperature, 750 - 500 = 250   K