A wire of length I metre carrying a current i ampere is bent in the form of a circle. The magnitude of magnetic moment is
iL2/4π
iL2/2π
iL/4π
πiL2
The magnetic moment is given bypm=iA=iπr2Given that 2πr=L or r=(L/2π)∴ pm=iπ(L/2π)2=iL2/4π