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Homework Help: Calculating H-Field with no free currents

  1. Oct 17, 2015 #1
    1. The problem statement, all variables and given/known data

    A cubic block of uniform linear magnetic material is placed in an otherwise uniform magnetic field
    Bo = Bo*. The block lies such that z^ is a normal of the top face.
    a)Compute the new H field everywhere.
    b)compute the new B field everywhere

    2. Relevant equations & The attempt at a solution

    My solution so far is based on the fact there are no free currents
    ie curl(H) = 0

    B = Bo +μo*M (1) (from hyper physics)
    =B/μo -M (2) (from lecture notes)

    substituting (1) into (2) I get:

    H = Bo/μo

    (I'm not sure if this is correct)

    computing the B-field then using B=μ*H
    I get:
    **B**=μr*Bo note: μr is relative permittivty (μ/μo)

    I'm not sure if this is correct regarding boundary conditions as M is discontinuous at the boundary of the cube.
    ie the div(M) ≠ 0

    and since div(H) = -div(M) (this can be shown by taking the divergence of (2) as div(B) = 0)

    so div(H) should also not equal zero, however given the H field I calculated that's clearly not the case.

    any tips for where I'm going wrong?

    thanks in advance!
  2. jcsd
  3. Oct 17, 2015 #2
    is this from an assignment or from a textbook question? i remember seeing something similar
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