Question

A solenoid has core of a material with relative permeability $500$ and its windings carry a current of $1$A. The number of turns of the solenoid is $500$ per metre. The magnetization of the material is nearly.

• A. $2.5\times {10}^3$A $m^{-1}$
• B. $2.5\times {10}^5$A $m^{-1}$
• C. $2.0\times {10}^3$A $m^{-1}$
• D. $2.0\times {10}^5$A $m^{-1}$

Answer 1

Answer: (B)

$2.5\times {10}^5$A $m^{-1}$

Here, $n=500$ turns/m
$I=1A,{\mu }_r=500$
Magnetic intensity, H$=nI=500m^{-1}\times 1A=500A{m}^{-1}$
As ${\mu }_r=1+\chi$
where $\chi$ is the magnetic susceptibility of the material
or $\chi =({\mu }_r-1)$
Magnetisation, M$=\chi$H
$=({\mu }_r-1)H=(500-1)\times 500A{m}^{-1}$
$=499\times 500A{m}^{-1}=2.495\times {10}^{5}A{m}^{-1}$
$=2.5\times {10}^{5}A{m}^{-1}$