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Velocity of electrons in a wire

  1. Jan 21, 2015 #1
    Electrons are moving in moves in all sorts of directions, causing the net electric charge to cancel out. But, when you apply a voltage, theres a small amount of electrons that will move towards the direction in the direction of the voltage. This is called the drift speed. Am I right? I read that the drift speed usually is 1/10000 of a second. How can you then obtain a current of 1 ampere, when 6.25*10^18 electrons has to move past a single point in one second, when the drift speed of the charge is that slow?
     
  2. jcsd
  3. Jan 21, 2015 #2

    Doc Al

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    Staff: Mentor

    There are lots of free electrons in a typical wire.

    Lots of electrons!

    See: Microscopic View of Electric Current
     
  4. Jan 21, 2015 #3
    Oh I see now. So the drift velocity of a single electron might be very slow, but because there are 8.5 * 10^28 electrons in a wire point of the wire, you still can get a pretty high current flow?
     
  5. Jan 21, 2015 #4

    Svein

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    200px-Newtons_cradle_animation_book_2.gif
    Have you seen this toy? It demonstrates the concept nicely. The time from an ball enters the ball chain to the end ball bouncing out is very short - but the internal balls (like the electrons in the wire) hardly move at all.
     
  6. Jan 21, 2015 #5

    anorlunda

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    Bravo Svein. This question comes up frequently on PF. That little video you posted explains it better than 10,000 words.
     
  7. Jan 21, 2015 #6

    Doc Al

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    Exactly.
     
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