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Homework Help: Electric Potential/Electric Potential Energy question

  1. Feb 17, 2005 #1
    We just started this stuff in my AP Physics class and I'm not catching on to it too quickly... At least problem solving-wise. I thought I had all the concepts down, but maybe not.

    Here's a question I'm having problems with:

    How do I go about this one? I'm sure it's a pretty simple problem because it's at the beginning of the chapter, but I guess I'm missing a connection or something.
     
  2. jcsd
  3. Feb 17, 2005 #2

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    well, voltage is potential energy per charge, and the charge on a single electron is -1.6*10^-19 couloumbs.
     
  4. Feb 17, 2005 #3
    I see, so what I did was:

    So 4.68 X 10^11 electrons was very close to the correct answer. Did I do this right?
     
  5. Feb 18, 2005 #4

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    Your work is a little sketchy. First of all, Joules/charge does not have units of "electrons", and I don't know what a negative number of electrons means. I get the idea of what you're doing, but you should be a lot more careful with units. Then, you seem to have forgotten the power of ten on the voltage.
     
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