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What if a photon interacts with a slower photon in front?

  1. Oct 6, 2015 #1
    What happens if a photon, photon b, interacts with a slower another photon, photon a, which is in front? Taking in account that these two photons are identical except for their speed, they are on the same path and direction as well.
  2. jcsd
  3. Oct 6, 2015 #2


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    Staff: Mentor

    Welcome to the PF.

    If the photons were identical, why would they have different speeds? If they have different wavelengths, they can have different speeds in a transparent media. And what do you mean by "interact"?
  4. Oct 6, 2015 #3


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    Welcome to PhysicsForums, Gunsno Tsui!

    berkeman posted while I was composing this, saying much the same as I was intending.

    All photons travel at the same speed, c (although effective velocity can vary by medium). So photons don't really overtake each other. Generally, photons do not interact with each other (although as with anything, there are some exceptions).
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