Define mean free path.

The expression of mean free path, if we consider that only one molecule is moving, for whom we are considering mean free path

Compare the mean free path of hydrogen with that of oxygen molecules under the same conditions.

If we consider the motion of all the molecules, the expression of mean free path is

Estimate the mean free path for a water molecule in water vapour at 373 K.

If the mean free path is ' lambda ' at one atm pressure then its value at 5 atm pressure is