Resistivity So,
or
...(i)
where ρ (rho) is called resistivity of the material of conductor.
यदि,
l = 1 m और a = 1 m
2 तब R = ρ ...(ii)
Thus, if we take 1 metre long piece of a substance having a cross-sectional area of 1 meter
2, then the resistance of that piece of the substance is called its resistivity.
Resistivity of a substance can also be defined as follows :
The resistance offered by a cube of a substance having side of 1 metre, when current flows perpendicular to the opposite faces, is called its resistivity.
Units of Resistivity From equation (i), we can write
So, SI unit of resistivity (ρ)
=
= ohm.m
Thus, the SI unit of resistivity is ohm. m (or Ω .m).