Question

What do you understand by the "resistivity" of a substance?

Answer 1

We know that resistance , `R=(rhol)/A`

So resistivity,  `rho=RA/l/`

When the area of cross-section, A is 1 m² and the length of the wire, l is 1 m, resistance is equal to resistivity.

Resistivity may be defined as the resistance offered by a conductor of length 1 m and area of cross-section 1 m².