Which of the following is not correct about relative magnetic permeability `(mu_(r))`?

Options

A. It is a dimensionless pure ratio.
B. For vacuum medium its value is one.
C. For ferromagnetic materials of `mu gt gt 1`
D. For paramagnetic materials `mu_(r) gt 1`

Answer

D

Explanation

Relative magnetic permeability
`mu_(r)=("magnetic permeability of material"(mu))/("permeability of free space"(mu_(0)))`
It is a dimensionless pure ratio and for paramagnetic materials `mu gt 1`