A quantity of monoatomic gas undergoes a process in which pressure is changed linearly with volume. The pressure and volume are changed from initial value $\left(p_0 V_0\right)$ of final value $\left(3 p_0, 3 V_0\right)$. The heat absorbed by the gas during the process is

An ideal gas having initial pressure $p$, volume $V$ and temperature $T$ is allowed to expand adiabatically until its volume becomes 4 V , while its temperature falls to $\frac{T}{2}$. If the work done by the gas during the expansion is $\alpha p V$, the value of $\alpha$ is

At what temperature, an oxygen molecule has the same rms velocity as the hydrogen molecule has at 20 K ?

A hole of diameter 5 cm is drilled in a metal sheet at $30^{\circ} \mathrm{C}$. The linear expansion of metal is $2 \times 10^{-5} \mathrm{~K}^{-1}$. The diameter of the hole when the temperature is raised to $230^{\circ} \mathrm{C}$, is equal to