The average velocity attained by some particle such as an electron due to the influence of an electric field is termed as the drift velocity. The movement or the motion of the particles is assumed to be along a plane and hence the motion can also be referred to as the axial drift velocity.
Consider a current of length l and cross sectional area A. When a potential difference V is applied across its ends, the current produced is I. If n is the number of electrons per unit volume in the conductor and the vd drift velocity of electrons, then the relation between current and drift velocity is
Under given physical conditions such as temperature, pressure etc., for a given conductor
