The magnetised wire of moment $M$ and length $l$ is bent in the form of semicircle of radius $r$. Then its…
The magnetised wire of moment $M$ and length $l$ is bent in the form of semicircle of radius $r$. Then its magnetic moment is
$\frac{2 M}{\pi}$
$2 M$
$\frac{M}{\pi}$
zero
Solution
On bending a wire its pole strength remains unchanged whereas its magnetic moment changes.
New magnetic moment,
$
M^{\prime}=m(2 r)=m\left(\frac{2 l}{\pi}\right)=\frac{3 M}{\pi}
$
