Define Magnetisation of a sample..??...
Answers
Answer:
classical electromagnetism, magnetization or magnetic polarization is the vector field that expresses the density of permanent or induced magnetic dipole moments in a magnetic material.
What is Magnetization?
The magnetization of a given sample material M can be defined as the net magnetic moment for that material per unit volume.
Mathematically,
magnetization
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Let us now consider the case of a solenoid. Let us take a solenoid with n turns per unit length and the current passing through it be given by I, then the magnetic field in the interior of the solenoid can be given as,
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Now, if we fill the interior with the solenoid with a material of non-zero magnetization, the field inside the solenoid must be greater than before. The net magnetic field B inside the solenoid can be given as,
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Where Bm gives the field contributed by the core material. Here, Bm is proportional to the magnetization of the material, M. Mathematically,
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Here, µ0 is the constant of permeability of a vacuum.
Let us now discuss another concept here, the magnetic intensity of a material. The magnetic intensity of a material can be given as,
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From this equation, we see that the total magnetic field can also be defined as,
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Here, the magnetic field due to the external factors such as the current in the solenoid is given as H and that due to the nature of the core is given by M. The latter quantity, that is M is dependent on external influences and is given by,
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Where χ is the magnetic susceptibility of the material. It gives the measure of the response of a material to an external field. The magnetic susceptibility of a material is small and positive for paramagnetic materials and is small and negative for diamagnetic materials.
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Here, the term µr is termed as the relative magnetic permeability of a material, which is analogous to the dielectric constants in the case of electrostatics. We define the magnetic permeability as,
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