Question

Which of the following is not correct about relative magnetic permeability $(\mu _{r} )$?

• A. It is a dimensionless pure ratio
• B. For vacuum medium its value is one
• C. For ferromagnetic materials $\mu _{r} > > 1$
• D. For paramagnetic materials $\mu _{r} > 1$

Answer 1

Answer: (D)

Relative magnetic permeability
$ \mu_{ r }=\frac{\text { magnetic permeability of material }(\mu)}{\text { permeability of free } \operatorname{space}\left(\mu_0\right)} $
It is a dimensionless pure ratio and for ferromagnetic materials
$\mu_{ r } > 1$.
For paramagnetic materials $\mu_{ r }<1$