The mean free path for gas, with molecular diameter \(d\) and number density can be expressed as:

1. \(\dfrac{1}{\sqrt{2} n πd^{2}}\)

2. \(\dfrac{1}{\sqrt{2} n^{2} πd^{2}}\)

3. \(\dfrac{1}{\sqrt{2} n^{2} \pi^{2} d^{2}}\)

4. \(\dfrac{1}{\sqrt{2} n πd}\)

The mean free path of gas molecules depends on:
(\(d=\) molecular diameter)

The mean free path of molecules of a gas, (radius \(r\)) is inversely proportional to:
1. \(r^3\)
2. \(r^2\)
3. \(r\)
4. \(\sqrt{r}\)