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B Phase difference

  1. Feb 13, 2017 #1
    Why phase difference of EM wave is changed 180 degrees reflected from denser medium?
    I will be glad if u give me the actual reason
     
  2. jcsd
  3. Feb 13, 2017 #2
  4. Feb 14, 2017 #3
    Thanks for ur help to provide this link... though I have little bit confusion, I will figure it out..
     
  5. Feb 14, 2017 #4

    sophiecentaur

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    The 'reason' can be explained in terms of a change of impedance and the requirement for continuity at the boundary. At the interface, there has to be continuity of E and H fields - as a wave crosses, if the ratio of E/H changes (different phase velocity) then there must be a reflected wave because all the energy can't pass through. One or other of the Electric or Magnetic fields in the reflected wave will be in anti phase so that there is no change in field across the boundary. Which one changes sign, depends on whether the impedance of the second is greater or less than the impedance of the first medium.
    This link may help or, maybe this one.
     
  6. Feb 15, 2017 #5
    Thanks for ur link
     
  7. Feb 16, 2017 #6
    An electromagnetic wave undergoes a phase change of 180° upon reflection from a medium that has a higher index of refraction than the one in which the wave is traveling.
     
  8. Feb 16, 2017 #7

    sophiecentaur

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    The OP wants a reason / explanation, though. Why would you expect the reflection from a lower index of refraction boundary to be in phase?
     
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