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B If r=0 then will the electric charge of two points=infinity?

  1. Dec 26, 2017 #1
    I found that the electric field at r=0 equals infinity. What if two negative charges were put infinitely close together so the electric field was infinite, then would the charge of those two points be -infinity as well?
     
  2. jcsd
  3. Dec 26, 2017 #2

    Nugatory

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    The infinity that you found is telling you that the ##F=Cq_1q_2/r^2## formula doesn't apply and shouldn't be used when ##r=0##. It works anywhere outside of a charged sphere (a very large number of interesting and problems, which is why we use it), but ##r## is never zero if you are outside the charged sphere.
     
  4. Dec 26, 2017 #3
  5. Dec 26, 2017 #4

    Nugatory

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    That is the equation for the field. I gave the equation for the force, which is the product of the field and the charge the field is acting on. So replace the ##C## in my formula with ##k## - it's Coulomb's constant either way - and identify ##Q_1## as the source charge and the two equations are saying the same thing.
     
  6. Dec 27, 2017 #5

    PeroK

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    ##\frac10 \ne +\infty##

    ##\frac10## is undefined.

    What you can say is that:

    As ##r \rightarrow 0, \ \frac1r \rightarrow +\infty##

    What this means that as ##r## gets smaller, ##1/r## increases without bound. But, at no time do you arithmetically arrive at ##+\infty##.
     
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