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Homework Help: Electric Charge Question

  1. Jan 29, 2009 #1
    1. The problem statement, all variables and given/known data
    A nonconducting disk of radius a lies in the z = 0 plane with its center at the origin. The disk is uniformly charged and has a total charge Q. Find Ez on the z axis at the following positions. (Assume that these distances are exact.)

    Z = a
    [__________]Q / (a2εo) - This is the format the answer should be in.

    2. Relevant equations

    Ez = [tex]\frac{kQz}{(z^2+a^2)^{3/2}}[/tex]

    k = 1/(2pi*εo)

    3. The attempt at a solution
    1. Ez = [tex]\frac{kQz}{(z^2+a^2)^{3/2}}[/tex]

    I filled in 'z' and 'k'

    2. Ez = [tex]\frac{Qa}{(a^2+a^2)^{3/2}*2\pi*\epsilon}[/tex]

    3. Ez = [tex]\frac{Qa}{(2a^2)^{3/2}*2\pi*\epsilon}[/tex]

    4. Ez = [tex]\frac{Qa}{8a^{3}*2\pi*\epsilon}[/tex]

    5. Ez = [tex]\frac{Q}{(16\pi*a^{2}*\epsilon}[/tex]

    6. [tex]1/16\pi[/tex]

    7. [_.1963495408_]Q / (a2εo) * Its wrong and I don't know what I did wrong. Please help
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Oct 19, 2010 #2
    Last edited by a moderator: Apr 25, 2017
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