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Current of a circuit

  1. Feb 14, 2007 #1

    jst

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

    In a DC circuit 8.41 x 10^19 electrons travel through a point in the circuit in two seconds. What current is in the circuit?



    2. Relevant equations


    I'm not sure at all on this. I was thinking it would be something like (charge*#electrons)/time, but I don't have a value for the charge


    3. The attempt at a solution

    Would it possibly be: (6.241 509 629 152 65×10^18 * 8.41 x 10^19)/2


    Thanks,

    Jason
     
    Last edited: Feb 14, 2007
  2. jcsd
  3. Feb 14, 2007 #2

    hage567

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    Homework Helper

    6.241 509 629 152 65×10^18

    This is how many electrons are needed for one coulomb of charge. What you want is to find the charge of one electron, if you are going to use your equation the way it is.
     
  4. Feb 14, 2007 #3

    rdx

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    As I understand the problem you need to convert the number of electrons to amperes. The ampere is a coulomb/sec and 1 electron is 1.602e-19 coul. I get 6.75 amps.
     
  5. Feb 14, 2007 #4

    Kurdt

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    1 ampere is 6.24x1018 electrons passing a point in a second. Since you know how many pass in two seconds you need to divide half the number given in the question by the number given in the definition.

    EDIT: All posted in the same minute and I'm last :rolleyes: Figures
     
  6. Feb 14, 2007 #5

    jst

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    Thanks to everyone! It's funny, I think I might have figured out before reading your posts.

    See what you think:

    =((# of electrons)*(charge of electron))/time

    =
    ((8.41*10^19)*(1.6*10^-19))/2

    =6.728


    ...at least it maches up with one of the possible solutions :)

    Thanks again,

    Jason
     
  7. Feb 14, 2007 #6

    jst

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    It was right...big thanks to everyone.

    Jason
     
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