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lys04
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- Homework Statement
- What's the difference between B, H and M in magnetism?
- Relevant Equations
- B, H, M
As the homework statement suggests
B, H, and M represent different magnetic fields and magnetization in materials. B, or the magnetic flux density, measures the total magnetic field, including contributions from free currents and bound currents. H, or the magnetic field strength, measures the magnetic field produced by free currents in a material. M, or the magnetization, indicates the density of magnetic moments in a material, showing how much a material is magnetized in response to an external magnetic field.
The relationship between B and H in a material is described by the equation B = μH, where μ is the permeability of the material. This equation indicates that B depends on both the magnetic field strength H and the material's ability to conduct magnetic lines of force, represented by its permeability.
Magnetization (M) plays a crucial role in determining how a material responds to an external magnetic field. It represents the extent to which a material becomes magnetized when exposed to a magnetic field and contributes to the overall magnetic field within the material. The magnetization is a vector quantity that can vary with the applied field strength and the material's properties.
In different types of materials, B, H, and M behave differently. In free space, B and H are directly proportional. In linear magnetic materials, B and H are related through a constant permeability. In ferromagnetic materials, M can be significantly large, leading to complex hysteresis behavior, where the relationship between B and H is nonlinear and path-dependent due to the material's magnetic history.
Magnetic susceptibility (χ) is a dimensionless quantity that indicates how susceptible a material is to becoming magnetized in response to an applied magnetic field. It relates the magnetization (M) to the magnetic field strength (H) through the equation M = χH. Materials can be classified based on their susceptibility: diamagnetic materials have negative susceptibility, paramagnetic materials have positive but low susceptibility, and ferromagnetic materials have high positive susceptibility, indicating strong magnetization effects.