Resistance of a conductor is given by ,
where is the specific resistance, is the length and is the cross-sectional area of the conductor.

Now, when and . So specific resistance or resistivity of a material may be defined as the resistance of a specimen of the material having unit length and unit cross-section. Hence, specific resistance is a property of a material and it will increase with the increase of temperature, but will not vary with the dimensions (length, cross section) of the conductor.