Question

A magnetized straight wire has a magnetic moment M .it is bent into a semi circular arc,its magnetic moment becomes

Answer 1

The magnetic moment of the wire will become 2M / π

Explanation:

Initial magnetic moment M=ml

when it is bent in a semi-circular wire the effective length between the poles become 2R

whereas  πR=l

R=l/π

Therefore, new M(new) = ml eff

                                     =m×2×R

​

                                    = m x 2 x l / π

                                    = 2M / π

So the magnetic moment is 2M / π