The resistivity of certain conductor with circular cross-sectional area and length depends only on the the distance r from the axis of the conductor as with . What is the equivalent resistance in Ohms of the conductor?
The connection between the electric field and the current density (current per unit area ) is given by This relation is equivalent to the traditional Ohm's Law and is known as the microscopic form of Ohm's Law. Therefore a non-uniform resistivity in a material implies that the current is not uniformly distributed over its cross section.