Question

Efficiency of a reversible heat engine working between a sink at temperature 30° C and source at temperature 90° Cis ;

Answer 1

Efficiency of the reversible engine is given by the following formula

$\eta = 1 - \frac{T_2}{T_1}$

here

$T_2$ = temperature of sink in kelvin = 30 + 273 = 303 k

$T_1$ = temperature of source in kelvin = 90 + 273 = 363 k

now as per above formula

$\eta = 1 - \frac{303}{363}$

$\eta = 1 - 0.835 = 0.165$

so the efficiency of the engine will be 16.5%