Drift velocity

The drift velocity that a particle such as an electron attains due to an electric field. Also see the velocity definition.Also see the given link to know about average velocity.

Since current is proportional to drift velocity, which is, in turn, proportional to the magnitude of an external electric field, Ohm's law can be explained in terms of drift velocity.
Drift velocity is expressed in the following equations: , where J_drift is the current density, σ is charge density in units c/m³, and v_avg is the average velocity of the carriers (drift velocity).

Example:Calculate the drift velocity of electrons in a metal conductor of area of cross-section lO^Wfor a current of 20A. Assume that there are 8-4 x 10²⁸ electrons per cubic metre; Charge on the electron = 1-6 x 10~¹⁹C.
Solution
We know that
I = n₀ev_dA; Drift Velocity v =——
"n^eA
₌_20_
84 x 10²⁸ x 1 -6 x 10~¹⁹ x 10^-5 = 1-485 xlO'W¹