Question

using the concept of a free electron in a conductor, derive the espression for the conductivity of a wire in terms of number density and relaxation time. hence obtain the relstion between current density and the applied electric field

Answer 1

PS- No. Denisty (n) = no of eleectrons in unit volume.

And Volume = Distance × Area, where Distance = velocity × Time..

( im just filling up the requisite minimum words in the answer, real answer is attached :) )