An ideal Carnot heat engine has an efficiency of $30\%$. It absorbs heat from a hot reservoir at $727^{\circ}C$. The temperature of the cold reservoir is .... $^{\circ}C$.

The efficiency of a Carnot engine is $25 \%$,when the temperature of the sink is $300 \ K$. The increase in the temperature of the source required for the efficiency to become $50 \%$ is (in $K$)

$A$ Carnot engine operating between temperatures $T_1$ and $T_2$ has an efficiency of $0.2$. When $T_2$ is lowered by $45 \text{ K}$, its efficiency becomes $0.5$. The temperatures $T_1$ and $T_2$ are respectively:

Consider a Carnot engine working between $T_1 = 500 \ K$ and $T_2 = 300 \ K$ producing $1 \ kJ$ of mechanical work per cycle. Calculate the heat absorbed by the engine from the source. (in $kJ$)

The temperature of the sink of a Carnot engine is $300 \,K$ and the efficiency of the engine is $0.25$. If the temperature of the source of the engine is increased by $100 \,K$, the efficiency of the engine increases by:

$A$ Carnot engine whose low temperature reservoir is at $7\,^{\circ}C$ has an efficiency of $50\%$. It is desired to increase the efficiency to $70\%$. By how many degrees should the temperature of the high temperature reservoir be increased? (in $K$)