What is Resistivity?

Answer: A conductor with a unitary cross-sectional area and length has a unit electrical resistance. Every material has a property which is known as resistivity. It is used to compare the resistance between two objects to carry the flow of electric current.

Resistivity, denoted by the ⍴, which is a greek letter and is defined as resistance (R) of a subject, multiplied by a cross-sectional area (A), which is then divided by a length (l); = RA/l.  The unit of resistivity is therefore ohm-metre in the MKS (metre-kilogram-second) system. Resistivity can be stated in ohm-centimetre units if the lengths are measured in centimetres. The magnitude of resistivity is also influenced by the temperature of the substance; resistivity tables typically provide values at 20° C. Metallic conductors’ resistivity increases as temperature rises, whereas semiconductors’ resistivity, like carbon & silicon, decreases as temperature rises.