where ρ (rho) is called resistivity of the material of conductor.
= 1 m और a = 1 m2
तब R = ρ ...(ii)
Thus, if we take 1 metre long piece of a substance having a cross-sectional area of 1 meter2
, 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)
Thus, the SI unit of resistivity is ohm. m (or Ω .m).