Properties of a magnet
1. The pole strength ‘m’ of a magnet depends upon the nature of material of a magnet, its state of demagnetization & area of cross section of the magnet but is independent of any bend in the magnet.
2. For a bar magnet
3. On cutting a magnet in two identical pieces longitudinally (along the length) the pole strength of each part is halved as a result the dipole moment of each part becomes half.
4. On cutting a magnet in two identical pieces transversally (normal to length) the dipole moment of each part becomes as length of each part is halved.
5. A flexible magnet of length L, pole strength m & dipole moment M is bent into a semi circle. The dipole moment of this semicircle will be .
6. Demagnetization can be due to heating, hammering, passing AC through an electromagnet, applying demagnetizing field (i.e. a magnetic field in the reverse direction), aging.