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Incident and reflected wave

  1. Oct 19, 2012 #1
    When my book derives equations for reflection between two media it simply says something like this:
    Suppose a plane electromagnetic wave meets the boundary between two media. This gives rise to an incident and a reflected wave. But I am always puzzled. What is that states that there MUST be reflection? I mean a transmitted wave is also a solution to the wave equation so why can't a transmitted wave without a reflected wave be just as good as a solution. To sum up, it just all seems like guesswork to me.
     
  2. jcsd
  3. Oct 19, 2012 #2

    haruspex

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    it's reasonable to assume there is both a transmitted and a reflected wave because these include the case that there is not, i.e. when the amplitude turns out to be zero.
    The change in medium leads to a difference between the incident and transmitted waves. On various grounds, such as conservation of energy, you may be able to deduce that the reflected wave has nonzero amplitude.
     
  4. Oct 19, 2012 #3
    normal component of D and tangential component of E must be continuous across the boundary which imposes some restriction on reflection and transmission.
     
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