1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: 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


    User Avatar
    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.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook