Which of the following is correct regarding drift velocity.

Options

A. When there is an electric field inside a conductor, the electrons drift slowly opposite to field with constant velocity.
`v = (e tau)/(m) E = kE`
`tau` : relaxtion time (average time taken by electrons in successive collision with atoms of material) depends on temperature
`k` : depends on material of conductor and its temperature.
B. The drift velocity is very small `(~= 10^-4 m//sec)` as compared to thermal speed of electrons at room temperature `(~= 10^6 m//sec)`
C. Drift velocity depends on the nature of metal, i.e., relaxation time `tau`. With rise in temperature relaxation time and hence drift velocity will decrease
D. All options are correct

Answer

D