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Electric Potential & Sphere

  1. Feb 8, 2009 #1
    1. The problem statement, all variables and given/known data
    http://img156.imageshack.us/img156/2111/picture2ox5.png [Broken]


    2. Relevant equations
    N/A


    3. The attempt at a solution
    The correct answer is supposed to be: V1 > V2 > V3 > V4 = V5 = V6

    But it is kind of weird...

    since charge only accumulates at the surface, you would think that V1=V4=V5=V6=0.

    My question is: Why is V1 randomly higher?...
     
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Feb 8, 2009 #2
    hi erinec,

    it is the resultant electric field which is zero in a sphere (due to charge accumulation on the surface) but a zero fiel means a constant potential (and not zero potential) , thats why V4=V5=V6

    the capacitance of a charged sphere is C=4*pi*eps0*R, this means smaller C for the smaller sphere. Now it is Q=C*V -> V=Q/C -> the surface of the smaller sphere has a higher potential V (for a charge coming from infinity) than the surface of the larger sphere. Inside of the smaller sphere, the potential is again constant. This gives V1>V4=V5=V6
     
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