The efficiency of a Carnot engine operating with reservoir temperatures of $100\,^{\circ}C$ and $-23\,^{\circ}C$ will be

$A$ Carnot engine takes $300$ calories of heat from a source at $500 \,K$ and rejects $150$ calories of heat to the sink. The temperature of the sink is (in $\,K$)

What is the theoretical efficiency of a heat engine?

$A$ Carnot heat engine has an efficiency of $20 \%$. The energy is supplied to the engine at the rate of $2 \text{ kW}$. The output power of the engine is (in $\text{ W}$)

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

$A$ reversible engine converts one-sixth of the heat input into work. When the temperature of the sink is reduced by $62^\circ C$,the efficiency of the engine is doubled. The temperatures of the source and sink are: