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Need help understand electro magnetic waves

  1. Mar 31, 2004 #1
    How do electro magnetic waves travel?
    if i am not mistaken waves are defiend as disturbances in a medium
    so do electro magnetic waves travel through a certain medium? if so how is this medium formed or does it exist every where in the universe and does not need to be formed ?
    Last edited: Mar 31, 2004
  2. jcsd
  3. Mar 31, 2004 #2


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    Staff: Mentor

    Electromagnetic radiation is different from other waves in that it does not require a separate medium on which to propogate. Part of the implication of this is that the speed of light is observed to be constant by all observers regardless of a frame of reference (as opposed to the speed of the car next to yours, which depends on your speed/frame of reference).
  4. Mar 31, 2004 #3


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    Staff Emeritus
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    Electromagnetic waves are self propagating. According to Maxwell's equations a Magnetic field is created by a changing Electric field, and an Electric field is created by a changing Magnetic field. This interaction propagates through space exchanging energy between the electric and magnetic fields.
  5. Mar 31, 2004 #4


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    "if i am not mistaken waves are defiend as disturbances in a medium"

    You are mistaken. "waves" are defined as anything that obeys the "wave equation" partial differential equation. That does not require a medium.
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