Question

State two ways in which a magnet can be demagnetized.

Answer 1

A magnet is formed when the magnetic dipoles in the ferromagnetic material are aligned in the same directions, causing a net magnetic field in the same direction. So, demagnetizing the magnet is basically randomizing this alignment by any means so that the net magnetic field produced will be zero or very negligible.

Complete step by step answer:
So, to demagnetize a magnet we have to take some external measures which will randomize the alignment/orientation of the magnetic dipoles in the given magnetic material causing it to be permanently destroyed i.e. they lose their magnetic properties.
The two ways in which a magnet can be demagnetized are:
1. Demagnetizing a magnet by heating: When we heat a magnet, it causes the electrons inside the orbit to spin and move to a higher state which creates a force of repel between nearby electrons.Because of this, some electrons are not aligned in the same spin as other electrons resulting in the decrease of magnetism of the material.In short, this heat energy provided frees the magnetic dipoles from their ordered alignment causing the long-range order of dipoles to be destroyed and hence the material is demagnetized.
2. Demagnetization by keeping the magnet in a reverse magnetic field (Usually inside a solenoid): A magnet can also be demagnetized by keeping it in a reverse magnetic field causing it to neutralize the magnetic field, due to which the magnetic dipoles are no longer aligned or they get randomized.

Note: When demagnetizing a magnet by heating the demagnetization of any material occurs only above a specific temperature called curie temperature.A magnetizer- demagnetizer is a tool or device which applies a strong enough magnetic field in reverse direction to the field of given magnetic material so as to change or neutralize the magnetic field. This tool is useful for magnetizing or demagnetizing iron and steel tools.