A thin bar magnet has dipole moment M . If this is bent in the form of semicircle , then find the new dipole moment .

Explanation

`pi R = L`
`M = q_(m) L " " … (i) M' = q_(m) xx 2R R = (L)/(pi)`
`= q_(m) xx (2L)/(pi)`
`M' = (2M)/(pi)`