A Carnot engine, whose efficiency is `40%`, takes in heat from a source maintained at a temperature of 500K. It is desired to have an engine of efficiency `60%`. Then, the intake temperature for the same exhaust (sink) temperature must be:

Explanation

`eta=1-(T_(2))/(T_(1)), 0.4=1-(T_(2))/(500)rArrT_(2)=300K`
`0.6=1(T_(2))/(T_(1)^(1))=1-(300)/(T_(1)^(1))=(300)/(0.4)=750K`