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Homework Help: An old nugget of a question: potential nucleus due to uniform charge sphere.

  1. Apr 3, 2008 #1
    1. The problem statement, all variables and given/known data

    Ast stated above: Biut i just cant get the correct answer!

    radius of sphere = a

    charge ze contained

    2. Relevant equations

    by gauss: E= (ze)*r/4pi(epsilon)*a^3 at any point within the sphere.

    and

    dv=r^2*sin(theta)dTheta*dphi*dr

    Energy density= 0.5*epsilon*E^2

    3. The attempt at a solution

    letting energy= integral(energy density)dv

    with limits: r= 0-a, theta= 0-pi, phi=0- 2pi

    i get wrong answer:

    (ze)^2/80epsilon*pi*a ration between top and bottom, should be 3(ze)^2/20epsilon*pi*a any ideas?

    many thanks!
     
  2. jcsd
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