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Homework Help: Basic Electricity Question - Potential Electric

  1. Feb 1, 2007 #1
    1. The problem statement, all variables and given/known data

    Question: a plate carries a charge of -3.0 uC, while a rod carries a charge of +2.0 uC. How many electrons must be transferred from the plate to the rod, so that both objects have the same charge?


    3. The attempt at a solution

    N= q/e = -2.0e-6/-1.6e-19 = 1.25e13 electrons transferred

    something doesn't seem right about this problem. the prof didnt mark this wrong, but he marked -2.0e-6 C wrong? anyone with the fix?
     
  2. jcsd
  3. Feb 1, 2007 #2

    Galileo

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    If you transfer 2uC from the rod to the plate, what will be the charges on both objects?
     
  4. Feb 1, 2007 #3
    -3.0 uC and +2.0 uC ...when you sum them up you get -1.0 uC? each with -0.5 uC? then, 2.5 uC when you subtract from 3.0 uC?

    find how many electrons in 2.5 uC? is that how much is transferred?

    too many questions!!!!:confused: :confused: :confused:
     
  5. Feb 1, 2007 #4
    think thats right, eg taking away from one and giveth to the other;
    -3-deltaC=2+deltaC so -2.5uC
     
  6. Feb 1, 2007 #5
    ^^that's it right? just calculate electrons for 2.5 uC and that's that right?
     
  7. Feb 1, 2007 #6
    You're good best I can tell, but technically its -2.5uC, some profs might not care, others most definitely will.
     
    Last edited: Feb 1, 2007
  8. Feb 1, 2007 #7
    appreciate it doc. i'll go ahead and take your word.
     
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