$\therefore \quad \rho=\frac{\mathrm{V}}{\mathrm{V}_{\mathrm{d}} \mathrm{lne}}$

Here $\mathrm{V}=$ potential difference

$\mathrm{I}=$ length of wire

$\mathrm{n}=\mathrm{no} .$ of electrons per unit volume of conductor.

$\mathrm{e}=\mathrm{no.}$ of electrons

Placing the value of above parameters we get resistivity

$\rho=\frac{5}{8 \times 10^{28} \times 1.6 \times 10^{-19} \times 2.5 \times 10^{-4} \times 0.1}$

$=1.6 \times 10^{-5} \,\Omega m$