Define magnetisation ?

Magnetisation is the process by which a material becomes magnetized, meaning it acquires magnetic properties and can attract or repel other magnetic materials. This can occur through the alignment of the magnetic domains within the material, creating a net magnetic field. Magnetisation can be induced by applying an external magnetic field or by bringing the material into contact with a magnet.

Magnetization (M) is a vector quantity that measures the strength and direction of the magnetic field produced by a material in response to an applied magnetic field. It is defined as the magnetic moment per unit volume of the material:

M = μ₀(χ)H

where:

M is the magnetization
μ₀ is the vacuum permeability (4π x 10^-7 T m/A)
χ is the magnetic susceptibility
H is the applied magnetic field

The magnetic susceptibility (χ) is a dimensionless quantity that characterizes the material's response to an applied magnetic field. It can be positive or negative, indicating the degree to which the material is magnetized or demagnetized, respectively.

Materials with high magnetic susceptibility are easily magnetized and have strong magnetic fields, while materials with low magnetic susceptibility are difficult to magnetize and have weak magnetic fields.

Magnetization is an important property for understanding the behavior of magnetic materials and their applications in various devices and technologies, such as magnets, magnetic sensors, and magnetic storage devices.