An engine is supposed to operate between two reservoirs at temperature $727^oC$ and $227^oC.$ The maximum possible efficiency of such an engine is

Which one of the following gases possesses the largest internal energy

If sink and source temperature of a refrigerator are $4^{\circ} C$ and $15^{\circ} C$ respectively. Then efficiency of refrigerator is

A household refrigerator with a coefficient of performance $1.2$ removes heat from the refrigerated space at the rate of $60\ kJ/min$ .What would be cost of running this fridge for one month ( $30$ days) ....... $Rs.$ (assuming each day it is used for $4$ hours and cost of one electrical unit is $6\ Rs$ .) 

$P-V$ diagram for two gases during adiabatic process are shown in the figure by curves $A$ and $B$ are for

The coefficient of apparent expansion of mercury in a glass vessel is $153 \times 10^{-6}/\,^oC$ and in a steel vessel is $144 \times 10^{-6}/\,^oC$. If $\alpha $ for steel is $12 \times 10^{-6}/\,^oC$, then $\alpha $ that of glass is