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Homework Help: De Broglie and other Quantum Questions

  1. Apr 21, 2009 #1
    Hi, just some quantum physics questions. I've given them all a good go, the first two just require checking, but the rest I'm rather stuck on. They're the last questions in about 20 other ones, and my head now hurts. :(

    Any hints are very much appreciated!

    1. The problem statement, all variables and given/known data

    I firstly got converted the 5eV to joules which gave m 8 x 10-19. I then divided that by the planck's constant to get my final answer of 1.21 x 1015Hz

    I got the wavelength of 2.49 x 10-7, by dividing the speed of an EM wave by the answer to A.

    I'm afraid this is where I get stuck. The possible equations that I know are KE = 0.5mv2 and hf = φ + ½ mv2max but here I am unsure of the theory. :(

    Pretty sure this is the particle model. Unsure of how to calculate the wavelength though, any ideas?

    I'm pretty sure this is the wave model. Same as the previous question.

    Thanks for reading!
  2. jcsd
  3. Apr 21, 2009 #2


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    17 c: If you supply energy hf to the electron, and W of this energy is used up to remove it from the metal, how much of the energy is left as kinetic energy?

    18 a: The de Broglie wavelength is given by p = h/λ.
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