Calculate the ratio of the mean free paths of the molecules of two gases having molecular diameters 1 Ao and 2 Ao. The gases may be considered under identical conditions of temperature, pressure and volume.

Hint: The mean free path depends on the diameters of the molecules.
Step 1: Write down the formula of the mean free path.
Mean free path of a molecule is given by,
                                               l=12d2n
where n = number of molecules/ volume
d = diameter of the molecule
Step 2: Find the ratio of mean free paths of the gases.
Now, we can write, l1d2
Given,                                    d1=1 Ao, d2=2 Ao
As                                         l11d12 and l21d22
 So,                                l1l2=d2d12=212=41
Hence,                               l1:l2=4:1