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Electromagnetic wave; the classical model

  1. Oct 27, 2004 #1
    Electromagnetic wave; the classical model....

    There appears to me to be an obvious flaw in the classical version of electro magnetic waves (before we even consider quantum theory. :rolleyes: ) Forgive me if I'm wrong but surely fields cannot travel as waves - after all, a field permeates space, getting weaker with distance, so how exactly can these fields actually travel forward as a wave?

    Thanks in advance. :rofl:
  2. jcsd
  3. Oct 27, 2004 #2

    Claude Bile

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    Maxwell's equations say they can. A static field permeates space and gets weaker with distance, yes, but electromagnetic waves are not static fields, they are dynamic (vary with time).

  4. Oct 27, 2004 #3

    James R

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    The fields don't travel. At any position in space, the field (either electric or magnetic) simply oscillates as the wave goes past. A wave is just an excitation of the local electromagnetic field.
  5. Oct 28, 2004 #4
    Fields and waves are different concept, but I supposed you're talking about optical field here? Then yeah, optical field from a point source, for instance, gets weaker with distance. But for field propagation in the form of plane wave, it doesn't get weaken as long as the medium is not lossy.
  6. Oct 28, 2004 #5
    Optic is just a particular cases of Electromagnetic .. so the thing you said appky to eletromagnetic too
  7. Oct 28, 2004 #6
    the wave isn't "moving" its creating an electric and magnetic field infront of it self, its not moving its propagating, a change in electric field creates the magnetic field in front of it which is also changing, and then electric field is created in front of that...and so on..