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Magnetism: Biot-Savart Law

  1. Nov 30, 2005 #1
    Suppose an electron orbits a proton at a distance of 'r' with speed 'v'.
    How could i determine the magnitude of the magnetic field at the location of the proton?

    I thought it would make sense to use The Biot-Savart Law, but i dont know where to begin:
    [tex]dB = \frac{\mu_o}{4\pi} \frac{I ds x r}{r^2} [/tex]
    (where [tex]ds x r[/tex] is a cross product of ds and r (unit vector) )
    Last edited by a moderator: Nov 30, 2005
  2. jcsd
  3. Nov 30, 2005 #2


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    Homework Helper

    You'll be doing an integration around the circumference of the orbit. The vectors ds and r will always be perpendicular so you can ignore the vector operation and focus on magnitude.

    A helping relationship would be that of current and electron flow. By definition:

    J = nqv

    where J is the current density, n is the electron density, q is the charge, and v is the average drift velocity. Since you have only one electron, you could probably assume I = qv/C, where C is the orbit's circumference.
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