Question

The dimensions of a bar magnet are $10cm\times 20cm\times 20cm$. It's pole strength is $200$ $Am$. It's intensity of magnetization is :

• A. ${10}^{-4}$ A/m
• B. $2\times {10}^{-4}$A/m
• C. $2\times {10}^{-6}$ A/m
• D. ${10}^6$ A/m

Answer 1

Answer: (D)

${10}^6$ A/m

Intensity of magnetization, $I=\frac{M}{V}$

where $V=Al$ = Volume

$M$ is magnetic moment

Magnetic moment $M=Pl$, usually $l$ is taken to be the longest side as poles lie on it.

Hence,

$I=\frac{Pl}{Al}$
$I=\frac{P}{A}$
$=\frac{200}{2\times {10}^{-2}\times {10}^{-2}}$

$={10}^{6}A/m$