Define the term current density of a metallic conductor. Deduce the relation connecting current density and conductivity of the conductor when electric field E, is applied to it.

Prove that the current density of a metallic conductor is directly proportional to the drift velocity of electrons.

Prove that electric current density of a metallic conductor is directly proportional to the drift speed of electrons?

Find out the resistivity of a conductor in which a current density 2.5 xx 10^6 A m^-2 is found to exist, when an electric field of 15 V m^-1 is applied on it.

Drift velocity in a metallic conductor: At room temperature there are large number of free electrons having zero average velocity, but when electric field is applied, the free electrons start moving in a direction opposite to the direction of the applied field with a velocity called drift velocity. The magnitude of electric field set up across the ends of the conductor is given by

Drift velocity in a metallic conductor: At room temperature there are large number of free electrons having zero average velocity, but when electric field is applied, the free electrons start moving in a direction opposite to the direction of the applied field with a velocity called drift velocity. Magnitude of acceleration produced in each electron by the electric field is