In changing the state of a thermodynamic system from state $A$ to state $B$, the heat supplied to the system is $Q$ and the work done by the system is $W$. The change in its internal energy is

The first law of thermodynamics is given by:

$A$ system goes from $A$ to $B$ via two processes $I$ and $II$ as shown in the figure. If $\Delta U_1$ and $\Delta U_2$ are the changes in internal energies in the processes $I$ and $II$ respectively, then the relation between $\Delta U_1$ and $\Delta U_2$ is

Why does a gas get heated on compression?

The change in the internal energy of a mass of gas,when the volume changes from $V$ to $2V$ at constant pressure $P$,is given by (where $\gamma = C_P / C_V$):

$1 \text{ cm}^3$ of water at its boiling point absorbs $540 \text{ calories}$ of heat to become steam with a volume of $1671 \text{ cm}^3$. If the atmospheric pressure = $1.013 \times 10^5 \text{ N/m}^2$ and the mechanical equivalent of heat = $4.19 \text{ J/calorie}$, the energy spent in this process in overcoming intermolecular forces is ..... $\text{cal}$. (in $\text{cal}$)