A magnetised wire of magnetic moment `'M'` and length `'l'` is bent in the form of a semicircle of radius `'r'`. The new magnetic moment is

Explanation

The initial magnetic moment of the wire of length 2l and pole strength m is M=m x 2l
Now, the magnetic moment of the half straight part of the wire is
`M. = m xx l = M/2`
For the semicircular part, let r be the radius of the semicircle. Separation between the dipoles is now = 2r Also, r = `l/n`
The magnetic moment of the arc is
`M.. = m xx 2r = M/pi`
Total magnetic moment =M + M" = ` M/2 + M/pi`