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Current Question?

  1. Sep 7, 2008 #1
    A copper wire of cross sectional area 2 mm^2 carries a current of 10 A. How many electrons pass through a given cross sectional of the wire in one second?
     
  2. jcsd
  3. Sep 7, 2008 #2

    Doc Al

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    Staff: Mentor

    What's the definition of current?
     
  4. Sep 7, 2008 #3
    Err V= IR?

    But I dont know how to relate with Area...
     
  5. Sep 7, 2008 #4

    Doc Al

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    Nope. That's Ohm's law. Hint: What does the unit Ampere mean? 1 A = ??
    Perhaps the area is irrelevant. :wink:
     
  6. Sep 7, 2008 #5
    Err

    Ampere = Charge / Time
    So

    Charge = Ampere / Time

    ooh
    we find the charge
    and since
    one electron has a charge of 1.6 x 10^-19
    thus, we divide the charge by the charge of one electron...

    is it correct?
     
  7. Sep 7, 2008 #6

    Doc Al

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    Staff: Mentor

    Right!
    Careful: If Current = charge/time then charge = current * time.
    Good!
     
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