AP TET Paper 2 Math and Science Model Paper 4

Concept:Resistivity is the material-dependent constant in the relation between resistance and conductor dimensions.Explanation:Resistance $R$ is proportional to length $L$ and inversely proportional to area $A$.This gives $R = \rho \frac{L}{A}$, where $\rho$ is resistivity.Rearranging, $\rho = R \frac{A}{L}$.Substitute SI units: $R$ in ohm ($\Omega$), $A$ in $\mathrm{m}^2$, $L$ in $\mathrm{m}$.So, $\rho = \Omega \times \frac{\mathrm{m}^2}{\mathrm{m}} = \Omega \cdot \mathrm{m}$.Thus, the SI unit of resistivity is ohm-metre.Resistivity does not depend on length or area; it depends on the material and temperature.Answer:Option B: ohm metre.