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Homework Help: Magnetic Field in polarisation ?

  1. Feb 26, 2009 #1
    Why is only electric field considered when we discuss the phenomenon of polarisation ? What about the magnetic field ?
     
  2. jcsd
  3. Feb 26, 2009 #2

    lanedance

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    i assume you are talking about light?

    magnetic field as always perp to the electric, so will be polarised in the same manner but rotated 90deg
     
  4. Feb 27, 2009 #3
    i think its because the direction of magnetic field is helical whereas the electric field is straight .
     
  5. Feb 27, 2009 #4

    lanedance

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    ahhh... no the magnetic polarisation will be the same as the electric

    ie linearly polarised light has both linearly polarised eletric & magnetic fields, both at 90deg to teh directino of propogation & to each other

    similarly cicularly polarised light has both cicularly polarised eletric & magnetic fields, still both at 90deg to the direction of propogation & to each other

    try finding the equation for a plane wave and check it out
     
  6. Feb 27, 2009 #5
    I am not saying that the polarised light will not have magnetic field , it will have it but genreally in polarisation we don't talk abt the mag field & i think the reason i gave must be it .
     
  7. Feb 28, 2009 #6

    lanedance

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    for linearly polarised light the magnetic field will be lineraly polarised not helical, so that reason is not correct

    have a look here
    http://en.wikipedia.org/wiki/Electromagnetic_radiation

    if you want to get into the philosophical side of things then we probably usually talk about electric field as the relative strength is B = E/c. So in terms of interacting with things the electric part is probably more significant.
     
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