Current loop as a magnetic dipole


The magnetic moment of a bar magnet is where qm is pole strength and 2l is length of magnet. Its direction is from − qm  to + qm.

A current carrying solenoid when suspended freely stays in north-south direction and attracts bits of iron. This shows that a current loop behaves as a magnetic dipole.

The dipole moment of current loop is

 m = NIA ampere – metre2

where N = number of turns in loop,

A = area of loop,

I = current in the loop.