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Charge Density Expression

  1. Dec 8, 2018 #1
    1. The problem statement, all variables and given/known data
    A charge Q is uniformly distributed throughout a nonconducting sphere of radius R. Write the expression of the charge density in the sphere?

    2. Relevant equations
    Charge density ρ=dQ/dV
    Gauss's Law ∫EdA = E(4ϖr^2)

    3. The attempt at a solution
    If Q is uniform then ρ=Q/dV and the volume of a sphere is 4/3ϖr^3 then I think charge density would just be ρ=Q/(4/3ϖr^3).
    This is suspiciously simple so I would just like external input on the problem. I have a feeling that I may need to use Gauss's Law somehow.
  2. jcsd
  3. Dec 8, 2018 #2


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    That's all there is to it. ##Q## could be anything uniformly distributed across volume ##V## and the density is, by definition, ##Q/V##.
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