Question

The mean free path of a molecule of He gas is a its mean free path along any arbitary coordinate axis will be.

Answer 1

mean free path of a gaseous molecule is average path length covered between two successive collision.

It is given by $\lambda =\frac{kT}{\sqrt{2}\pi d^{2}P}$

Where, K= Boltzman constant

$\lambda$= mean free path

d= diameter of the particle

P= pressure of the gaseous molecule in a container

mean free path along arbitrary coordinate axis of He gas is also $a$.