How can a material be magnetised?

A material can be magnetised by placing it in a strong magnetic field or by passing an electric current through it.

Magnetisation of a material involves aligning the tiny magnetic domains within the material in the same direction. This can be achieved in two main ways. The first method is by placing the material in a strong magnetic field. The magnetic field forces the magnetic domains within the material to align in the same direction, thus magnetising the material. This process is known as induced magnetisation.

The second method is by passing an electric current through the material. When an electric current is passed through a material, it creates a magnetic field around it. This magnetic field then aligns the magnetic domains within the material in the same direction, magnetising the material. This process is known as electromagnetism.

The ability of a material to be magnetised depends on its properties. Some materials, like iron and steel, are easily magnetised because they have a large number of magnetic domains that can be aligned. These materials are known as ferromagnetic materials. Other materials, like copper and aluminium, are not easily magnetised because they have fewer magnetic domains that can be aligned. These materials are known as paramagnetic materials.

It's also important to note that the magnetisation of a material is not permanent. When the magnetic field or electric current is removed, the magnetic domains within the material can return to their original, random orientations. This causes the material to lose its magnetisation. However, some materials, like steel, retain their magnetisation for a longer period of time. This is known as residual magnetism.