The efficiency of an ideal Carnot engine working between temperatures $T_1$ and $T_2$ is $1/3$. If the temperature of the sink is reduced by $40 \%$,then its efficiency will be: (in $\%$)

An engine performs $2000 \,J$ of mechanical work and discards $4000 \,J$ of heat each cycle. What is the thermal efficiency of the engine (in $\%$)?

When the absolute temperature of the source of a Carnot heat engine is increased by $25 \%$,its efficiency increases by $80 \%$. The new efficiency of the engine is (in $\%$)

In a Carnot engine,the temperature of the sink is $27 \, ^\circ C$ and the temperature of the source is $927 \, ^\circ C$. If the work done by the engine to reject heat from the source to the sink is $12.6 \times 10^{6} \, J$,what is the heat absorbed from the source?

For a Carnot engine,the efficiency is given by $W/Q_1 = 1/6$. If the temperature of the sink is reduced by $62^{\circ}C$,the efficiency doubles. The initial temperatures of the sink and the source are,respectively:

For which of the following options will the efficiency of a Carnot engine be the highest?