Question

If refractive index and dielectric constant of the material of a glass slab is $\frac{3}{2}$ and $3$ respectively then magnetic permeability of the glass is (in $SI$ system )

• A. $5.32\times {10}^{-7}$
• B. $3.94\times {10}^{-7}$
• C. ${10}^{-7}$
• D. $9.42\times {10}^{-7}$

Answer 1

The correct option is D $9.42\times {10}^{-7}$

Given: $\epsilon =3,n=\frac{3}{2}$

Solution: We know relation between refractive index ,relative permeability & dielectric constant i.e.

${\mu }_r=\frac{n^2}{\epsilon }$

After putting values we get,${\mu }_r=\frac{3}{4}$

Remember here that magnetic permeability is asked and not relative permeability

${\mu }_r=\frac{\mu }{{\mu }_0}$

$\mu$=$9.42\times {10}^{-7}$H/m