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Thread: I'm having difficulty in solving this problem. Please HELP!

  1. #1 I'm having difficulty in solving this problem. Please HELP! 
    Forum Freshman Sudhamsu's Avatar
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    I've tried to solve this one very hard, but it just doesn't crack!
    Please help..

    Question:
    Photoelectrons are liberated by Ultra-Violet rays (of wavelength = 3000 Angstrom) from a metallic surface for which the Photoelectric Threshold wavelength is 4000 Angstrom. Calculate the de Broglie's Wavelength of the emitted electrons.

    If you know how to solve this, please explain it in detail.


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  3. #2  
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    Show your working so far it will help decide where you may be going wrong.


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  4. #3  
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    The electron will have kinetic energy equal to the energy of the incident photon minus the work function, that being the energy of a photon with the threshold frequency. Do you know how to find a photon's energy from its frequency?

    Knowing the electron's kinetic energy you could find its momentum, then use de Broglie's equation to solve for your answer. I think that's the way you would do it.
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