Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Additionl field proportional to magnetisation?

  1. Feb 23, 2012 #1
    Magnetisation of a sample is net dipole moment per unit volume i.e. M = m(net) / V

    It turns out that magnetic field due to the material is proportional to magnetisation
    i.e. B(magnetic field due to material) = μM
    Any explanation to this? It should be proportional but any proof for this or is it just experimental
     
  2. jcsd
  3. Feb 23, 2012 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    hi jd12345! :smile:
    isn't it B = µo(M + H) = µH ?

    M and H are measured in electric units, as electric current/distance (Am-1),

    (magnetic dipole moment is charge times distance/time, = distance times charge/time = distance times electric current, in A.m)

    but B is measured in magnetic units, as magnetic flux/area (Wb.m-2)

    there's no fundamental reason for this … they're all the same thing! :rolleyes: … it's just more convenient in practice! :biggrin:

    so to convert between these different species of units, we must have a universal conversion factor, and that's µo (in Wb.A-1m-1 or T.m.A-1) :wink:

    µ (as opposed to µo) is just a trick to make it look as if B is proportional to H on its own
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Additionl field proportional to magnetisation?
Loading...