The length of a magnetised steel wire is l and the magnetic moment is m. It is bent into the shape of L with two sides equal. The magnetic moment now will be

Question

The length of a magnetised steel wire is l and the magnetic moment is m. It is bent into the shape of L with two sides equal. The magnetic moment now will be (A) m / 2 (B) 2 m (C) √2 m (D) m / √2

Tardigrade Admin · Accepted Answer

If qm is strength of each pole, then m=qm × l. When the wire is bent into L shape effective distance between the poles =√(l / 2)2+(l / 2)2=l / √2 ∴ m prime =qm × (l/√2)=(m/√2) (m text will remain unchanged)

Q. The length of a magnetised steel wire is $l$ and the magnetic moment is $m$ . It is bent into the shape of $L$ with two sides equal. The magnetic moment now will be

$m /2$

$2 m$

$2 m$

$m / 2$

If $q_{m}$ is strength of each pole, then $m = q_{m} \times l$ . When the wire is bent into $L$ shape effective distance between the poles
$= (l /2)^{2} + (l /2)^{2} = l / 2$
$∴ m^{'} = q_{m} \times \frac{l}{2} = \frac{m}{2}$ $(m will remain unchanged)$

Q. The length of a magnetised steel wire is l and the magnetic moment is m. It is bent into the shape of L with two sides equal. The magnetic moment now will be

m/2

2m

2​m

m/2​

If qm​ is strength of each pole, then m=qm​×l. When the wire is bent into L shape effective distance between the poles =(l/2)2+(l/2)2​=l/2​ ∴m′=qm​×2​l​=2​m​ (m will remain unchanged)

Q. The length of a magnetised steel wire is $l$ and the magnetic moment is $m$ . It is bent into the shape of $L$ with two sides equal. The magnetic moment now will be

$m /2$

$2 m$

$2 m$

$m / 2$

If $q_{m}$ is strength of each pole, then $m = q_{m} \times l$ . When the wire is bent into $L$ shape effective distance between the poles
$= (l /2)^{2} + (l /2)^{2} = l / 2$
$∴ m^{'} = q_{m} \times \frac{l}{2} = \frac{m}{2}$ $(m will remain unchanged)$