Question

Obtain the relation between current density and conductivity

Answer 1

Let I current flow through a conductor when applied potential difference V volt. then, from ohm’s law,

I=

R

V

But R=ρ

A

L

Therefore,

I=

ρ

A

L

V

⟹

A

I

=

ρL

V

but,

A

I

=J,

L

V

=E

Hence, J=σE

⟹σ=

E

J