The plot that depicts the behavior of the mean free time τ (time...

The average time taken by a moving particle between successive collisions or impacts is referred to as the mean free time $\left(τ\right)$.

The average distance a moving particle travels between successive collisions or impacts is referred to as the mean free path $\left(\lambda\right)$.

$\lambda = \dfrac{kT}{\sqrt{2}\pi{d}^{2}P}$

and ${v}_{rms} = \sqrt{\dfrac{3RT}{M}}$

So, the mean free time $τ = \dfrac{\lambda}{{v}_{rms}}$

Therefore, $τ ∝ \dfrac{1}{\sqrt{T}}$