$A$ sample of $0.1 \, g$ of water at $100^{\circ} C$ and normal pressure $(1.013 \times 10^5 \, N m^{-2})$ requires $54 \, cal$ of heat energy to convert to steam at $100^{\circ} C$. If the volume of the steam produced is $167.1 \, cc$,the change in internal energy of the sample is ....... $J$.

The internal energy change in a system that has absorbed $2 \, kcal$ of heat and done $500 \, J$ of work is ...... $J$.

Consider one mole of perfect gas in a cylinder of unit cross-section with a piston attached as shown in the figure. $A$ spring (spring constant $k$) is attached (unstretched length $L$) to the piston and to the bottom of the cylinder. Initially,the spring is unstretched and the gas is in equilibrium. $A$ certain amount of heat $Q$ is supplied to the gas,causing an increase in volume from $V_0$ to $V_1$.
$(a)$ What is the initial pressure of the system?
$(b)$ What is the final pressure of the system?
$(c)$ Using the first law of thermodynamics,write down a relation between $Q, V_0, V_1, P_a$ and $k$.

$A$ monoatomic gas of $n$ moles is heated from temperature $T_1$ to $T_2$ under two different conditions: $(i)$ at constant volume and $(ii)$ at constant pressure. The change in internal energy of the gas is

What is the net amount of heat entering the system in a cyclic process equivalent to?

Is it possible to convert internal energy into work or mechanical energy?