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Electron accelerating in a bent wire

  1. Apr 30, 2015 #1
    If I run a current through a wire with a 90 degree turn, what prevents the electrons from continuing out of the wire is a straight forward path? What force accelerates them in the direction of the wire?
  2. jcsd
  3. Apr 30, 2015 #2


    Staff: Mentor

  4. Apr 30, 2015 #3
    Thanks a lot!
  5. Apr 30, 2015 #4
    Even without current and without a bent, we have the problem of electrons moving with speeds of tens of thousand of m/s through the metal.
    Did you ever wondered why they don't get out of the metal?
    I am not saying that it's not a good question. Just that is a more general one.
  6. Apr 30, 2015 #5
    On a related note, the average speed of electrons (the http://en.wikipedia.org/wiki/Drift_velocity ) is miniscule. For a 3A current through a 1mm diameter copper wire, the drift velocity is 0.28 mm/s.
  7. Apr 30, 2015 #6


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    it does happen, but only with very high voltages and currents ( but it's still not a speed of electrons issue)
    @rumborak covered that in his last post

    When I was in the telecommunications industry, I would very often see this effect on sharp - 90 deg bends in cables that has been struck by lightning
    It didn't matter if it was an underground multipair telephone cable, a coaxial cable or a lightning earthing cable on a pole/mast

    It was amazing to see how the current from a lightning strike would travel down 100's of metres - several km's of cable in a straight line and then when that cable would do a bend to be spliced into the main trunk cable the current would punch a hole in the apex of the bend and go to ground

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