While studying electron drift through a metallic conductor the magnitude of the drift velocity per unit electric field (called mobility) is equal to? (Where e is charge on an electron, m is mass of an electron, E is the electric field, τ is relaxation time and n is the number of free electrons per unit volume)

While studying electron drift through a metallic conductor the magnitu

1.	While studying electron drift through a metallic conductor the magnitude of the drift velocity per unit electric field (called mobility) is equal to? (Where e is charge on an electron, m is mass of an electron, E is the electric field, τ is relaxation time and n is the number of free electrons per unit volume)
A.	ne2τE/m
B.	ne2τ/m
C.	eτ/m
D.	σE
Answer» D. σE