$A$ Carnot engine operates with a source at $227^{\circ}C$ and a sink at $27^{\circ}C$. If the source supplies $50 \ kJ$ of heat energy,the work done by the engine is (in $kJ$)

The maximum possible efficiency of a heat engine is ...........

$A$ Carnot engine uses an ideal monoatomic gas first and then an ideal diatomic gas. If the source and sink temperatures are $411^{\circ}C$ and $69^{\circ}C$ respectively,and the engine extracts $1000 \, J$ of heat in each cycle,then the area enclosed by the $PV$ diagram is ........ $J$.

$A$ Carnot engine having efficiency $60 \%$ receives heat from a source at a temperature $600 \text{ K}$. For the same sink temperature, to increase its efficiency to $80 \%$, the temperature of the source is (in $\text{ K}$)

$A$ reversible engine has an efficiency of $\frac{1}{4}$. If the temperature of the sink is reduced by $58^{\circ}C$,its efficiency becomes double. Calculate the temperature of the sink in $^{\circ}C$.

Which type of process is performed in an ideal engine?