Question

Find the expression for resistivity of a material and state the SI unit of resistivity.

Answer 1

As we know resistance can be expressed as $R\propto \frac{l}{A}$.

$\Rightarrow R=\rho \frac{l}{A}$

where $\rho =$ resistivity of the material

$l=$ length of the material

$A=$ cross-sectional area of the conductor

Hence the resistivity of the conductor can be written as $\rho =\frac{RA}{l}$

The SI unit of resistivity is $\Omega -m$