MHTCET 5 May 2025 Shift 2 Paper

Concept:Resistivity is a material property that relates resistance to the dimensions of a conductor.Explanation:The relation is $R = \rho \frac{L}{A}$, where $R$ is resistance, $L$ is length, and $A$ is cross-sectional area.Rearranging gives $\rho = R \cdot \frac{A}{L}$.Now substitute the SI units: $R$ is in ohm ($\Omega$), $A$ is in $\mathrm{m}^2$, and $L$ is in $\mathrm{m}$.So, $[\rho] = \Omega \cdot \frac{\mathrm{m}^2}{\mathrm{m}} = \Omega \, \mathrm{m}$.Thus, resistivity has the unit ohm-metre.Answer:The SI unit of resistivity is $\Omega \, \mathrm{m}$. Hence, the correct option is A.