CBSE Class 10 Science 2019 · Paper 31/3/1 · Question 1

Electrical resistivity of a material is the resistance of a conductor made of that material having unit length and unit area of cross-section, that is, a conductor $1$ m long with an area of cross-section of $1{\text{m}}^2$. It is the constant $\rho$ in $R=\rho \frac{l}{A}$, so $\rho =\frac{RA}{l}$; its SI unit is the ohm metre ($\Omega \text{m}$), and it depends only on the nature of the material (and its temperature), not on the size or shape of the conductor.