Ask a Teacher

what is meant by ferro magnetism?

Those substances which when placed in an external magnetic field, are strongly magnetized in the direction of the applied external magnetic field are called ferromagnetic substances.

e.g. iron, nickel, cobalt etc.

Since the strong induced magnetic field is in the direction of the applied magnetic field, the resultant magnetic field inside the ferromagnetic substance is very large; often thousand times larger than the external field. It is clear that ferromagnetism is a very strong form of magnetism. When external magnetic field is removed, some ferromagnetic substances retain magnetism.