Compressibility of real gas will be less than ideal gas: $\left(\mathrm{T}=\right.$temperature of gas, ${\mathrm{T}}_{\mathrm{b}}=$Boyle's temperature of gas$)$

The average velocity of gas molecules is $400 \mathrm{m} {\sec }^{-1}$. Calculate its r.m.s. velocity at the same temperature.

The value of $d$ in $\mathrm{cm}$ (shown in the figure), as estimated from Graham's law, is:

According to the kinetic theory of gases, between two successive collisions, a gas molecule travels