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The reciprocal of permeability is magnetic reluctivity. In SI units, permeability is measured in henries per meter (H/m), or equivalently in newtons per ampere squared (N/A 2). The permeability constant μ 0, also known as the magnetic constant or the permeability of free space, is the proportionality between magnetic induction and magnetizing ...
The vacuum magnetic permeability (variously vacuum permeability, permeability of free space, permeability of vacuum, magnetic constant) is the magnetic permeability in a classical vacuum. It is a physical constant , conventionally written as μ 0 (pronounced "mu nought" or "mu zero").
Using SI units, the magnetic induction B is related to H by the relationship = (+) = (+) =, where μ 0 is the vacuum permeability (see table of physical constants), and (1 + χ v) is the relative permeability of the material.
A practical unit for permeability is the darcy (d), or more commonly the millidarcy (md) (1 d ≈ 10 −12 m 2). The name honors the French Engineer Henry Darcy who first described the flow of water through sand filters for potable water supply. Permeability values for most materials commonly range typically from a fraction to several thousand ...
where c is the defined value for the speed of light in classical vacuum in SI units, [4]: 127 and μ 0 is the parameter that international standards organizations refer to as the magnetic constant (also called vacuum permeability or the permeability of free space).
where χ is called the volume magnetic susceptibility, and μ is called the magnetic permeability of the material. The magnetic potential energy per unit volume (i.e. magnetic energy density) of the paramagnet (or diamagnet) in the magnetic field is:
Unit name Symbol Base units E energy: joule: J = C⋅V = W⋅s kg⋅m 2 ⋅s −2: Q electric charge: coulomb: C A⋅s I electric current: ampere: A = C/s = W/V A J electric current density: ampere per square metre A/m 2: A⋅m −2: U, ΔV; Δϕ; E, ξ potential difference; voltage; electromotive force: volt: V = J/C kg⋅m 2 ⋅s −3 ⋅A ...
In the Gaussian system, unlike the ISQ, the electric field E G and the magnetic field B G have the same dimension. This amounts to a factor of c between how B is defined in the two unit systems, on top of the other differences. [3] (The same factor applies to other magnetic quantities such as the magnetic field, H, and magnetization, M.)