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Homework Help: Why, IF electrons really orbited atoms, would they lose energy?

  1. Dec 11, 2013 #1
    1. The problem statement, all variables and given/known data

    Why, IF electrons really orbited atoms, would they lose energy?
    2. Relevant equations

    3. The attempt at a solution
    I realise they're meant to emit light. But why? I understand vaguely that the E field might be changing with time, since you have a changing magnetic flux... but where does the changing E field come from? Unless I guess it's just a self supporting process (changing B field *causes* changing E here...) - is that just what a light ray is??

    Many Thanks!!!
  2. jcsd
  3. Dec 11, 2013 #2
    Draw up a picture of a simple atom, like a hydrogen atom. Ignore the contribution from the atom core to the electric field.

    Pick a random point and write down the electric field in that point, draw it again after half a period (For the orbiting electron).

    Will the electric field be different in the two pictures.
  4. Dec 11, 2013 #3
    Oh right, for sure. The electron is at a different distance from the point! Sorry!
  5. Dec 11, 2013 #4
    A moving charge always produces a changing E field, that should be obvious. Take any fixed point P in space. At some time, the charge Q is at distance A from P. At some other time, Q is at distance B from P. Because A and B are different, the E field at P must also be different.
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