How ohm's law is derived form drift velocity relates current formula ?

Explanation

The current flowing through a conductor is,
`I = nAev_d`
But ` v_d = (eE)/m, tau `
`I = nAe (eE)/m , tau `
` I = (n A e^2)/(mL) tau V " "[because E = V/L]`
where V is the potential difference. The quantity `(mL)/(n Ae^2 tau)` is a constant for a given conductor, celled electrical resistance (R).
`I prop V`
The law states that, at a constant temperature, the steady current flowing through a conductor is directly proportional to the potential difference between the two ends of the conductor.