Question

The mean free path for a gas, with molecular diameter $d$ and number density $n$ can be expressed as :

• A. $\frac{1}{\sqrt{2}n\pi d}$
• B. $\frac{1}{\sqrt{2}n\pi d^2}$
• C. $\frac{1}{\sqrt{2}{n}^2\pi d^2}$
• D. $\frac{1}{\sqrt{2}{n}^2{\pi }^2{d}^2}$

Answer 1

Answer: (B)

Mean free path for a gas sample ${\lambda }_m=\frac{1}{\sqrt{2}\pi d^{2}n}$
where d is diameter of a gas molecule and n is molecular density