Question

An iron rod of cross sectional area $4c{m}^2$ is placed with its length parallel to a magnetic field of intensity $1600A/m$. The flux through the rod is $4\times {10}^{-4}Wb$. The permeability of the material of the rod is (in $Wb/Am$)

• A. $0.625\times {10}^{-3}$
• B. $6.25\times {10}^{-3}$
• C. $1.625\times {10}^{-3}$
• D. $1.125\times {10}^{-3}$

Answer 1

Answer: (A)

$0.625\times {10}^{-3}$

$A=4\times {10}^{-4}{m}^2$
Magnetic field intensity $H=1600A/m$
$\varphi =4\times {10}^{-4}$
$\varphi =B.A$
$4\times {10}^{-4}=4\times {10}^{-4}\times B$
$B=1T$
Relation between magnetic field intensity and Magnetic field:
$H=\frac{B}{\mu }$
$\mu =\frac{1}{1600}$
${\mu }_r=6.25\times {10}^{-4}$