# How does resistance relate to conductivity?

Resistance $R$ of a wire is given by :
$R = \rho \cdot \frac{l}{A}$ where $l$ is the length of the wire and $A$, its area of cross section.
$\rho$ is a constant for the given material at a particular temperature. It is called to resistivity or specific resistance of the material.
The conductivity ($\sigma$) is defined as,
$\sigma = \frac{1}{\rho}$