Write the equation for the mean free path of gas molecules.

(N/A) The mean free path $\lambda$ of gas molecules is defined as the average distance traveled by a molecule between two successive collisions. The formula for the mean free path is given by:
$\lambda = \frac{1}{\sqrt{2} \pi d^2 n}$
Where:
- $\lambda$ is the mean free path.
- $d$ is the diameter of the gas molecule.
- $n$ is the number density of the molecules (number of molecules per unit volume).