Question

The unit of permeability of vacuum $\left({\mu }_0\right)$ is __________.

• A. $\frac{N}{A^2}$
• B. $\frac{N}{A}$
• C. $NA$
• D. $\frac{J}{A^2}$

Answer 1

Answer: (A)

$\frac{N}{A^2}$

We know that
$B=\frac{{\mu }_0}{2\pi }\times \frac{i}{R}$
where $2\pi =$ dimensionless
${\mu }_0=\frac{2\pi \times B\times R}{i}$
$\therefore$ The unit of ${\mu }_0=\frac{B\times R}{i}$
$=\frac{newton-{ampere}^{-1}-{metre}^{-1}\times metre}{ampere}$
${\mu }_0=\frac{newton}{{ampere}^2}=\frac{N}{A^2}$