Question

What is absolute and relative permeability?

Answer 1

Absolute permeability:

1. In electrostatics, permeability is the measure of the ability of the material to allow the formation of magnetic lines of force or magnetic field within.
2. Absolute permeability refers to the permeability of the free space.
3. The absolute permeability is a constant and its value is given as:
   ${\mu }_0=4\mathrm{\pi }\times {10}^{-7}{\mathrm{Hm}}^{-1}$.

Relative permeability:

1. Relative permeability is the ratio of permeability of the substance to absolute permeability.
2. The ratio of permeability of a substance to the permeability of the vacuum is known as relative permeability:
   ${\mu }_r=\frac{\mu }{{\mu }_{{}_0}}$
   Where ${\mu }_r$ is the relative permeability, $\mu$ is the permeability of the substance, and ${\mu }_0$ is the permeability of the vacuum.
3. The relative permeability is a dimensionless quantity.