Question

The SI unit of specific resistance is

• A. $ohmm$
• B. $ohm{m}^{-1}$
• C. $ohm{m}^2$
• D. ${\left(ohm\right)}^{-1}$

Answer 1

The correct option is A

$ohmm$

Definition of Specific Resistance.

The measure of an electrical component with which it is opposing the flow of the electrons through it.

Mathematical representation of Specific Resistance.

It is reciprocal to conductivity. It is denoted as, $\rho =\frac{RA}{L}$ where, $R$ is the resistance, $A$ is the area of the cross-section through which the current (electrons) is passing, and $L$ is the length of the electronic component, taken into consideration.

The units of $R,A$ and $L$ is $\Omega ,m^2$ and $m$ respectively.

Substitute the units in the formula $\rho =\frac{RA}{L}$ as-

$\rho =\frac{\Omega \times m^2}{m}=\Omega -m$

Thus, the SI unit of specific resistivity is $ohm-m$. Option A is the correct answer.