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Homework Help: I (t ) =15 2 cos (2π 60t ) [A]

  1. Apr 21, 2009 #1

    A wire has a current given by
    i (t ) =15 2 cos (2π 60t ) [A].
    Determine how many electrons cross a particular point on the wire, moving from right to left, in
    the time interval 0 < t < 0.001

    I don't get this one. What equation do Ineed to use? I can't find the right one, but it seems so easy. :confused:
  2. jcsd
  3. Apr 21, 2009 #2


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    Hi XodoX! :smile:

    Hint: current = charge per time, so ∫(current)d(time) = charge :wink:
  4. Apr 21, 2009 #3
    Re: current/electrons

    I don't get it. Couldn't I just plug in the numbers and substract both equations?
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