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Homework Help: Designing a simple magnetic field gen with a straight wire. Need current density

  1. Dec 6, 2011 #1
    1. The problem statement, all variables and given/known data
    Need to design a simple magnetic field generator of radius a= 2mm. The solid metal wire must carry a current density, jw, uniformly distributed over its cross section. The current density that must be found must have a magnetic field at a radial distance of r= 8mm from the axis of the wire is 7.5 10^-13 Tesla. Ignore end effects. Must develop the equation using Ampere's Law as the beginning derivation.


    2. Relevant equations
    I=∫J*da
    A=r*r*∏
    B∫J*ds

    3. The attempt at a solution

    I am have been trying to start off this by drawing a diagram but I don't even think it is correct.

    http://imageshack.us/photo/my-images/440/finalprep.png/
     
  2. jcsd
  3. Dec 6, 2011 #2
    Also I forgot an equation jw inside is

    J=(I)/(∏*r*r)
     
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