State three classes of magnetic materials?

1. Ferromagnetic materials - These materials have strong magnetic properties and can be easily magnetized. Examples include iron, nickel, and cobalt.

2. Paramagnetic materials - These materials have weak magnetic properties and are only slightly attracted to a magnetic field. Examples include aluminum, platinum, and oxygen.

3. Diamagnetic materials - These materials have no permanent magnetic properties and are repelled by a magnetic field. Examples include copper, gold, and water.

1. Diamagnetic
2. Paramagnetic
3. Ferromagnetic