The average kinetic energy of thermal neutrons is of the order of (Boltzmann's constant $K_B = 8 \times 10^{-5} \text{ eV/K}$ and room temperature $T \approx 300 \text{ K}$)

Consider a rectangular block of wood moving with a velocity $v_{0}$ in a gas at temperature $T$ and mass density $\rho$. Assume the velocity is along the x-axis and the area of cross-section of the block perpendicular to $v_{0}$ is $A$. Show that the drag force on the block is $4\rho A v_{0} \sqrt{\frac{kT}{m}}$,where $m$ is the mass of the gas molecule.

Consider a gas with $n$ molecules. The average number of molecules moving in a fixed direction is ..........

In an ideal gas,if the masses of all molecules are doubled and their speeds are halved,then the ratio of initial and final pressures of the gas is

The kinetic energy of $1 \ g$ of $He$ gas at $272^{\circ}C$ is ........... $J$.

The pressure exerted by a gas is $P_0$. If the mass of the molecules is halved and their velocity is doubled,the pressure will become .......