Question

How to deduce ohm's law from equation of drift velocity?

Answer 1

Hence acceleration experienced by the electron is given by

$a= \large\frac{eE}{m}$

If τ is the average time between collisions, we can write the expression for velocity of drifting electrons in terms of electric field as

$v_d= \large\frac{eE}{m}$$\tau$

On combining this result with Equation, we obtain the expression for current :

$I= -neAv_d$

$\quad= -neA\large\frac{eE}{m}$$ \tau$

$\quad= \large\frac{-Ane^2 E}{m}$$ \tau$

$I= +\large\frac{ne^2A}{m} \frac{V}{l}$$\tau$

Vl=mne2τlA=R

we get,

ρ=1σ=mne2τ

Answer 2

Explanation:

Hence average drift velocity The amount of charge, crossing area A, in time Δt is = neAvdΔt = IΔt ... conductor. Hence deduce Ohm's law