Question

The resistivity of a conductor is expressed in ______.

Options

• \(\Omega\)

• \(\Omega \mathrm{m}\)

• \(\Omega \mathrm{m}^{-1}\)

• \(\Omega \mathrm{m}^{2}\)

Answer 1

The resistivity of a conductor is expressed in \[ {\underline{\boldsymbol{\Omega\,\mathrm{m}^{2}}}} \].

Explanation:

The resistivity of a conductor is given by \(\rho=\dfrac{RA}{l}\), where \(R\) is resistance, \(A\) is cross-sectional area, and \(l\) is length. Since resistance is measured in ohms (\(\Omega\)), area in \(\mathrm{m}^2\), and length in metres (\(\mathrm{m}\)), the SI unit of resistivity is \(\Omega\,\mathrm{m}\), not \(\Omega\,\mathrm{m}^2\).