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Homework Help: Threshold frequency

  1. Jun 21, 2004 #1
    Dear all

    The question is :
    A certain material has a work function of 0.4eV. What is the energy of a single photon of electromagnetic radiation at the threshold frequency for liberation of photoelectrons?

    Would u give me some hint how to find the threshold frequency at first ??

    thanks all

  2. jcsd
  3. Jun 21, 2004 #2
    Hint : Photoelectric Eqn
  4. Jun 22, 2004 #3
    can i assume the equation is:
    K.E = hf - work function = 0 ??

  5. Jun 22, 2004 #4

    Doc Al

    User Avatar

    Staff: Mentor

    Right. At the threshold frequency the photons have an energy just equal to the work function.
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