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Homework Help: Photon Question-Energy Quantization Question-please help!

  1. Oct 16, 2007 #1
    Photon Question-Energy Quantization Question---please help!

    This is a somewhat simple question I'm just unsure what relations to use. I found an equation relating number of protons to power and frequency but i'm not sure how to apply it to this case.


    Power = energy per unit time
    = (energy per photon) * (photon per unit time)
    = (h*f) * (photons per unit time)

    Power = wattage
    h = Planck's constant
    f = frequency.

    A certain laser outputs pure red light (photon energy 1.8 eV) with power 550 milliwatts (0.55 watts). How many photons per second does this laser emit?

  2. jcsd
  3. Oct 16, 2007 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Looks like you have the correct relations. Just be sure to convert everything to standard units: eV to Joules, mW to Watts.
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