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Sinusodial solution of EM equation

  1. Oct 30, 2007 #1
    what kind of sources of light generate sinusodially varying electric field that is solutions of the form
    [tex] E(x,t)=E_{o}(x,t) \sin(kx-\omega t)[/tex]
  2. jcsd
  3. Oct 30, 2007 #2


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    All light sources do.
  4. Oct 30, 2007 #3
    # Radiation needs "sinusodially varying electric field" For example, if a charged particle makes an oscillation in space, its electric field makes and an oscillation with a delay in time, according to the distance of the field point to the source.
    # And light is an EM radiation (which is visible.) So by definition every kind of light sources generate oscillating E fields.
  5. Oct 31, 2007 #4
    ues they do generate oscillating field but point sources generate spherical waves which are not sinusodial since they are inversely propotional to distance
  6. Oct 31, 2007 #5

    Meir Achuz

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    The extra spatial dependence is in the E_0(r,t) in the original post.
  7. Oct 31, 2007 #6


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    Then you need to be more specific and clearer in your question. Recalled that you asked about sources of light, and by "light", we automatically associated EM wave, not static E-field in electrostatics situations.

    So you have to figure out exactly what it is here that you want, and ask accordingly.

  8. Nov 1, 2007 #7
    sorry i meant solutions of the form [tex]E(x,t)=E_{0}\sin(kx-\omega t)[/tex]
  9. Nov 1, 2007 #8

    Claude Bile

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    We need to work in 3D if we want to talk about real sources.

    [tex]E(r,t)=E_{0}\sin(k.r-\omega t)[/tex]

    Is an infinite plane wave, no real source can produce such a wave.

    It is possible however to express a propagating wave of arbitrary spatial shape as a linear sum of plane wave components, much the same way we can describe a wave with an arbitrary shape in time as a linear sum of discrete sinusoidal frequencies.

    Last edited: Nov 1, 2007
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