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  2. Permeability (electromagnetism) - Wikipedia

    en.wikipedia.org/wiki/Permeability...

    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 force when forming a magnetic field in a classical vacuum.

  3. Air permeability specific surface - Wikipedia

    en.wikipedia.org/wiki/Air_permeability_specific...

    Measurement consists of packing the powder into a cylindrical "bed" having a known porosity (i.e. volume of air-space between particles divided by total bed volume). A pressure drop is set up along the length of the bed cylinder. The resulting flow-rate of air through the bed yields the specific surface by the Kozeny–Carman equation: [1]

  4. Permeability (materials science) - Wikipedia

    en.wikipedia.org/wiki/Permeability_(Materials...

    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 ...

  5. Electromagnetic wave equation - Wikipedia

    en.wikipedia.org/wiki/Electromagnetic_wave_equation

    The electromagnetic wave equation is a second-order partial differential equation that describes the propagation of electromagnetic waves through a medium or in a vacuum. It is a three-dimensional form of the wave equation. The homogeneous form of the equation, written in terms of either the electric field E or the magnetic field B, takes the form:

  6. Permeation - Wikipedia

    en.wikipedia.org/wiki/Permeation

    In physics and engineering, permeation (also called imbuing) is the penetration of a permeate (a fluid such as a liquid, gas, or vapor) through a solid.It is directly related to the concentration gradient of the permeate, a material's intrinsic permeability, and the materials' mass diffusivity. [1]

  7. Magnetic susceptibility - Wikipedia

    en.wikipedia.org/wiki/Magnetic_susceptibility

    where μ 0 is the vacuum permeability (see table of physical constants), and (1 + χ v) is the relative permeability of the material. Thus the volume magnetic susceptibility χ v and the magnetic permeability μ are related by the following formula: = (+).

  8. Vacuum permeability - Wikipedia

    en.wikipedia.org/wiki/Vacuum_permeability

    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").

  9. Fresnel equations - Wikipedia

    en.wikipedia.org/wiki/Fresnel_equations

    As before, we are assuming the magnetic permeability, µ of both media to be equal to the permeability of free space µ 0 as is essentially true of all dielectrics at optical frequencies. Amplitude coefficients: air to glass Amplitude coefficients: glass to air. In the following equations and graphs, we adopt the following conventions.