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A single moving charge constituite a current

  1. Feb 8, 2007 #1
    Can you tell whether a single moving charge constituite a current?Not necessarily steady current.I will be happy I we get a non-steady current.To have a non-zero current we need dq/dt not equal to zero.So at point in space,we measure dq/dt and it is 0 at time t,q at time t' and 0 again at time t".So at that point the current is q/(t"-t).Please justify...
  2. jcsd
  3. Feb 8, 2007 #2
    Well, think about it. Let's say we have a line of charge, and start running parallel to it with a velocity v. Then suddenly it's a current with a distribution equal to the charge distribution times v. Why shouldn't this apply to a point charge?
  4. Feb 8, 2007 #3
    ofcourse,now I can understand this.Thank you
  5. Feb 8, 2007 #4
    A single point charge moving does indeed constitute a current at that point in space. When we speak of a current in a wire, what we mean is the aggregate effect of every moving charge in that wire. What appears to us as a steady current is in fact the overlapping fields of an enormous number of charges passing us rapidly and giving the effect of a moving charge equally at every point in space.
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