The ability to oppose the current flow in a conductor is the resistivity of a material.
The electric field at any point within the wire is and the current density, , is the current flow in the wire.
Therefore, the specific resistance of the material of the wire is: is the electrical resistivity, is the Length of the material of a conductor, is the area of cross-section and is the resistance.
We know, Resistance, , so resistivity can be written as ,