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Homework Help: B and H in a magnetic material

  1. Jan 24, 2010 #1
    1. The problem statement, all variables and given/known data
    griffiths 6.13:
    Suppose the field inside a large piece of magnetic material is Bo, so that Ho = (1/uo)Bo - M. Now a small spherical cavity is hollowed out of the material. Find the field at the center of the cavity, in terms of Bo and M. Also find H at the center of the cavity, in terms of Ho and M.

    2. Relevant equations
    closed integral (H * dl) = Ifenc

    3. The attempt at a solution

    Well since I thought that the free current inside the cavity would be zero, that made H also zero. Because H was zero, M = 1/uo B.
    So M = uoHo / Bo.
    Therefore B = uo2Ho / Bo
    And H = 0 = uoHo / Bo - M.
    I guess I'm just confused because I'm not real sure how to approach the problem; this was all I could think of.

    btw, a link to the various symbols would obviously be welcomed.
  2. jcsd
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