$300 \, cal$ of heat is given to a heat engine and it rejects $225 \, cal$ of heat. If the source temperature is $227^{\circ} C$,then the temperature of the sink will be . . . . . . $^{\circ} C$.

The efficiency of a heat engine that works between the temperatures where Celsius-Fahrenheit scales coincide and Kelvin-Fahrenheit scales coincide is (approximately) (in $\%$)

The first operation involved in a Carnot cycle is

$A$ Carnot engine having an efficiency of $40\%$ takes heat from a source maintained at a temperature of $500 \ K$. If the efficiency is to be increased to $60\%$ while keeping the sink temperature constant,what should be the new source temperature in $K$?

$A$ Carnot engine has an efficiency of $50 \%$. If the temperature of the sink is reduced by $40 \, K$,its efficiency increases by $30 \%$. The temperature of the source will be $.... \, K$.

$A$ Carnot engine operates between two reservoirs of temperatures $900 \; K$ and $300 \; K$. The engine performs $1200 \; J$ of work per cycle. The heat energy (in $J$) delivered by the engine to the low-temperature reservoir in a cycle is: