Explain Resistivity.

Resistivity: Resistance R of a wire containing cross-sectional area A and length L maintain the relationship, - R α L and R α 1/A; that is resulting R α L/A or say R = ρ L / A; here ρ is the constant of proportionality and is termed as resistivity of a material and is termed as the resistance among the two opposite faces of a meter cube of that material. This unit of resistivity is ohm-m. Factors influencing resistivity are alloying, temperature and mechanical stressing and ageing.