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In electromagnetics, the term magnetic field is used for two distinct but closely related vector fields denoted by the symbols B and H. In the International System of Units, the unit of B, magnetic flux density, is the tesla (in SI base units: kilogram per second squared per ampere), [5]: 21 which is equivalent to newton per meter per ampere.
Measure for how the magnetization of material is affected by the application of an external magnetic field H/m L M T −2 I −2: intensive Permittivity: ε s: Measure for how the polarization of a material is affected by the application of an external electric field F/m L −3 M −1 T 4 I 2: intensive Plane angle: θ: Ratio of circular arc ...
In electromagnetism, the magnetic susceptibility (from Latin susceptibilis 'receptive'; denoted χ, chi) is a measure of how much a material will become magnetized in an applied magnetic field. It is the ratio of magnetization M ( magnetic moment per unit volume ) to the applied magnetic field intensity H .
A magnetic field contains energy, and physical systems move toward configurations with lower energy. When diamagnetic material is placed in a magnetic field, a magnetic dipole tends to align itself in opposed polarity to that field, thereby lowering the net field strength. When ferromagnetic material is placed within a magnetic field, the ...
Paramagnetic materials have a weak induced magnetization in a magnetic field, which disappears when the magnetic field is removed. Ferromagnetic and ferrimagnetic materials have strong magnetization in a magnetic field, and can be magnetized to have magnetization in the absence of an external field, becoming a permanent magnet .
A useful tool for dealing with high frequency magnetic effects is the complex permeability. While at low frequencies in a linear material the magnetic field and the auxiliary magnetic field are simply proportional to each other through some scalar permeability, at high frequencies these quantities will react to each other with some lag time. [36]
The magnetic flux density does not measure how strong a magnetic field is, but only how strong the magnetic flux is in a given point or at a given distance (usually right above the magnet's surface). For the intrinsic order of magnitude of magnetic fields, see: Orders of magnitude (magnetic moment) .
The resolution to this apparent problem lies in the fact that, as previously stated, no observers can measure the potentials; they measure the electric and magnetic fields. So, the combination of ∇ φ and ∂ A /∂ t used in determining the electric field restores the speed limit imposed by special relativity for the electric field, making ...