Question

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:
A. efficiency of Carnot engine cannot be made larger than `50%`
B. `1200K`
C. `750K`
D. `600K`

Answer 1

Correct Answer - C
(c) `0.4=1-(T_2)/500 and 0.6=1-(T_2)/(T_1)`
on solving we get `T_2=750K`