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Homework Help: Rate of energy

  1. Oct 28, 2008 #1
    1. The problem statement, all variables and given/known data

    In a certain region of space, there is a uniform magnetic field B = 4.49 × 10−5 T, parallel to the x-axis, and a uniform electric field E = 10.2 V/m, parallel to the y-axis.
    The permeability of free space is 4 pi ×10−7 N · m2.
    At what rate does energy cross a square area, 0.65 cm on a side, that is perpendicular
    to the z-axis?
    Answer in units of W.

    2. Relevant equations

    I = EB / permeability

    P = IA

    3. The attempt at a solution

    I = (10.2 V/m)(4.49 e-5)/ (4*pi*e-7)
    =364.449 A

    P=(364.449 A) (0.0065 m)
    =2.36892 W

    This answer is not right when I plug it into my online homework answers. :(
  2. jcsd
  3. Oct 28, 2008 #2


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