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Electrons are negative, same charges repel, then what about this?

  1. Dec 28, 2013 #1
    Cathode rays are the flow of election, since electrons are -vely charged, is it normal for the rays to travel almost in a bundle without getting dispersed due to it's repulsion?
    If you say it's because of its velocity, then if you imagine each electrons, they are at almost rest to eachother, then why won't they scatter?
    Lightning, they too do the same, how could they travel in a bundle without getting repelled eachother?
  2. jcsd
  3. Dec 28, 2013 #2


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    The parameters (width of the beam, current, acceleration, length, ...) are chosen in such a way that dispersion is not problematic.
    Dispersion exists, but the electrons are far away from each other and the travel time is very short in typical cathode ray tubes.

    You don't need a net charge for lightning, the atoms where the electrons are from are still there.
  4. Dec 30, 2013 #3
    When electricity arcs through air it forms a plasma path. The plasma path has lower resistance than regular air so the current follows it. Really big breakers actually blow air between the contacts as soon as they open to evacuate the plasma and extinguish the arc.
  5. Dec 30, 2013 #4

    Vanadium 50

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    As mfb points out, they do disperse. Just not so much that it is a problem.
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