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Homework Help: Proof involving Ampere's Law

  1. Apr 6, 2010 #1
    1. The problem statement, all variables and given/known data

    Ampere's Law states [tex]
    \int _C \vec{B} \cdot \vec{dr} = \mu_0 \ I
    [/tex] .

    By taking C to be a circle with radius r, show that the magnitude B = |B| of the magnetic field at a distance r from the center of the wire is [tex]
    B = \frac{\mu_0}{2 \pi} \ \frac{I}{r}

    3. The attempt at a solution

    I really don't know where to start. I don't know what the components of B are, so I don't know how I'm supposed to compute this integral.
    Last edited: Apr 6, 2010
  2. jcsd
  3. Apr 6, 2010 #2
    What do you know about the B-field at a distace r from the wire, magnitude-wise? How can you use this knowledge in computing the integral?
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