i. The bar magnet said to have pole strength +qm and -qm near the north and south poles respectively.
ii. As bar magnet has two poles with equal and opposite pole strength, it is called as a magnetic dipole.
iii. The two poles are separated by a distance equal to 2l.
iv. The product of pole strength and the magnetic length is called as magnetic dipole moment.
∴ \(\overset\rightarrow{m}\) = qm \((2\overset\rightarrow{l})\)
where, \(2\overset\rightarrow{l}\) is a vector from south pole to north pole.
