The heat energy absorbed by a system in going through a cyclic process shown in figure is

$P-V$ diagram of $2\,g$ of $He$ gas for $A \to B$ process is shown. What is the heat given to the gas ?

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

Three moles of an ideal monoatomic gas perform a cycle as shown in the figure. The gas temperature in different states are: $T_1 = 400\, K,\, T_2 = 800\, K,\, T_3 = 2400\, K$ and $T_4 = 1200\,K$ . The work done by the gas during the cycle is  .... $kJ$

One mole of an ideal gas $(C_p/C_v = \gamma )$ at absolute temperature $T_1$ is adiabatically compresses from an initial pressure $P_1$ to a final pressure $P_2$. The resulting temperature $T_2$ of the gas is given by

A carnot engine, having an efficiency of $\eta  = 1/10$ as heat engine, is used as a refrigetator. If the work done on the system is $10\,J$ , the amount of energy absorbed from the reservoir at lower temperature is .......... $\mathrm{J}$