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Homework Help: Point Charges Composing A Sphere

  1. Jun 17, 2012 #1
    1. The problem statement, all variables and given/known data

    I have a quick question about understanding the theory behind point charges and electrostatic potentials. I've not had any classes in electrodynamics, so I lack a comfortable foundation to help me think about these problems.

    I need to determine the electrostatic potential a certain distance from a charged sphere. I know you can view a sphere as a point charge and apply Gauss's Law, but the difference for me is that my sphere is made up of hundreds of individual charges composing this sphere. Each charge can be viewed as individual point charges and they all have the same value.

    My question is how do I get a single charge value for the sphere.

    2. Relevant equations

    E = Q / 4∏(ε0)r

    3. The attempt at a solution

    I thought about taking the (Q/r) portion of Guass's law and doing a summation over all the atoms, but with the amount of atoms making up the sphere this is unreasonable. Is there some simpler way to think about this problem?
  2. jcsd
  3. Jun 17, 2012 #2


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    Homework Helper

    welcome to physicsforums, RockMc. Is this really homework? This thread might be better in the classical physics section instead (if it is not homework).
  4. Jun 17, 2012 #3
    Ah, it's not homework! Thanks for the advice. I'll close this and move over to there!
  5. Jun 17, 2012 #4


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    Homework Helper

    Welcome to PF!

    Hi RockMc! Welcome to PF! :smile:

    Can't you just apply Gauss' law to any sphere round all the charges?
  6. Jun 17, 2012 #5


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    Homework Helper

    Excellent. I'll try to give helpful advice there.
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