Question

When a piece of a ferromagnetic substance is put in a uniform magnetic field, the flux density inside it is $4$ times the flux density away from the piece. The magnetic permeability of the material is:

• A. 1
• B. 2
• C. 3
• D. 4

Answer 1

The correct option is D 4

Given (flux density Inside)$=4$(flux density outside)

To find: Permeability of material$=?$

Solution:

We know that

$B=B_o{\mu }_r$

${\mu }_r=\frac{B}{B_o}$

$=\frac{4B_o}{B_o}$

${\mu }_r=4$.