A bar magnet of length ′l′ and magnetic dipole moment M is bent in the form of an arc as shown in figure. The new magnetic dipole moment will be:
Given that,
Length = l
Magnetic dipole moment = M
Now, the magnetic moment is
M=ml
According to figure
Now, the length is
l=π3×r
r=3lπ
Now, the new magnetic moment is
M′=m×3lπ
M′=3Mπ
Hence, the new magnetic dipole moment is 3Mπ