SSC JE Electrical Engineering 2017 Set 3 Paper

Drift velocity is the average velocity that a particle, such as an electron attains in a material due to an electric field.
$\mathit{N}\mathit{\alpha }=\mathit{\mu }\mathit{E}$
µ = electron mobility m${}^2$ /vs
E = electric field v/m
${\mathit{V}}_{\mathit{d}}$ = drift velocity m/s
Drift velocity of electron in silicon increase linearly with electric field at low value of electric field and gradually saturates at higher value of electric field Drift velocity at high electric field saturate due to upper limit of speed