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Permeability Of Light

  1. Feb 28, 2005 #1
    What does a substance's permeability of light depend on?
  2. jcsd
  3. Feb 28, 2005 #2


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    The permeability of free space,or the permeability of a substance, is the parameter that determines how the substance effects a magnetic field. It does not just apply to light but to all magnetic fields
  4. Feb 28, 2005 #3
    Is it because of visible light is a kind of electromagnetic wave?
  5. Feb 28, 2005 #4
    Visible light is only a small part of the Electromagnetic wave spectrum, ranging from radio waves, up to X-rays and Gamma Rays, with visible light somewhere in the middle of the scale.

    The parameter [tex]\mu_o[/tex] is the permeability of free space.
    [tex]\mu_r[/tex] is the relative permeability (analogous to [tex]\epsilon_r[/tex])

    It can be defined as [tex]B=\mu_0 (H+M)[/tex]

    Where B is the magentic induction field, H is the magnetic field strength and M is the magnetisation across the sample.
    or with some working:

    [tex]B = \mu_0 \mu_r H[/tex]

    Since [tex] M = \chi_m H[/tex]
    and [tex] \mu_r = (1+\chi_m)[/tex]
    ([tex]\chi_m[/tex] is magnetic susceptibility)
    relative permeability in a material is just some kind of a measure of how much of an applied magnetic field will be "used up" due to magnetisation in the material.

    Also it is said that B is what you pay for, H is what you get.
    Last edited: Feb 28, 2005
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