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Direction of reflected/refracted light

  1. Apr 13, 2013 #1
    Reflection/refraction of light is due to the absorption of photons by electrons in the governing atoms, and is then reflected/refracted with a different wavelength and direction. I understand why the light might be a different colour (wavelength), but I don't understand what causes the incident ray to be reflected/refracted in the direction it does...

    My question is: What is stopping the electron emitting the photons in a random direction?

    I thought it might have something to do with the absorption of the wave over time with respect to the wavelength of the light, but then red and blue are both reflected in the same direction, so it can't be that.

  2. jcsd
  3. Apr 13, 2013 #2


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    That is just one of many options.
    A different wavelength is rare.
    This is easier to understand if you consider light as wave, similar to water waves. All atoms of the surface are involved in reflection.
  4. Apr 13, 2013 #3
    A different wavelength is rare? I was under the impression objects are the colour they are due to the wavelengths of light that can be absorbed/emitted. So a red surface will absorb all the light and then emit light in the red frequencies?
  5. Apr 13, 2013 #4


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    A red surface reflects or scatters the red component of the incoming light and absorbs others. If you shine blue light on it, it appears dark/black, not red.
  6. Apr 15, 2013 #5

    Meir Achuz

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    That is wrong. R and R are wave phenomena (even for one photon) caused by the coherent interaction of the wave with
    ~10^10 atoms.
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