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    I don't know how to find the final energies of photons. I can find their momentum but not then their velocity, because their rest mass is zero.
    For example,
    2pc = E
    2ymvc = E

    but m is 0.. help

    There is no wavelength given.
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    (Original post by StarvingAutist)
    I don't know how to find the final energies of photons. I can find their momentum but not then their velocity, because their rest mass is zero.
    For example,
    2pc = E
    2ymvc = E

    but m is 0.. help

    There is no wavelength given.
    How have you found their momentum?

    Remember, the de Broglie wavelength of a particle (such as a photon) is given by lamda = h/p.

    The energy of a photon is then found from E = hf = hc/lamda.
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    (Original post by Ollie231213)
    How have you found their momentum?

    Remember, the de Broglie wavelength of a particle (such as a photon) is given by lamda = h/p.

    The energy of a photon is then found from E = hf = hc/lamda.
    I don't have the wavelengths though
    I got the momenta from E = pc, but this is their CM frame momentum.. do I just add the CM energy? But then they have the same energy, and according to the question, they don't..

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    (Original post by StarvingAutist)
    I don't have the wavelengths though
    I got the momenta from E = pc, but this is their CM frame momentum.. do I just add the CM energy? But then they have the same energy, and according to the question, they don't..

    Name:  16.png
Views: 26
Size:  3.5 KB
    Attachment 541377541379
    But if you have the momenta, can't you use that to work out the wavelengths?
 
 
 
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