Question

Write two examples of ferromagnetic substances.

Answer 1

Ferromagnetic substances are the substances which are magnetised strongly in the direction of field when placed in an external magnetic field. Most of the ferromagnetic materials are metals.

Complete step by step answer:
Ferromagnetic substances are those materials which get strongly magnetised when placed in an external magnetic field. They have a strong inclination to move from a region of weak magnetic field to strong magnetic field. i.e., ferromagnetic materials are strongly attracted towards a magnet.
The word ‘ferromagnetic’ is derived from ‘ferrous’ which means iron because iron was the first metal known to show magnetic attraction. Some other ferromagnetic materials are Cobalt, Nickel, Gadolinium, ferric oxide.

Additional Information: When ferromagnetic substances are heated at a high temperature, they transform to paramagnetic substances. The temperature at which ferromagnetic substance is converted to paramagnetic is known as Curie temperature.
Permeability of ferromagnetic substances is greater than one.
Ferromagnetic materials are grouped into small regions known as domains. Every domain behaves like a tiny magnet. The domains of a non-magnetised ferromagnetic material are oriented randomly such that their magnetic moments cancel out. When ferromagnetic materials are placed in an external magnetic field, these domains align themselves in the direction of the magnetic field immediately, creating a powerful magnetic effect.

Note: When the applied magnetic field is removed, even then a part of domain alignment remains in the same direction. So the body acts as permanent magnets. This property of ferromagnetic makes them suitable for making magnets.