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Work Function Question

  1. Apr 14, 2014 #1
    Hi all,

    I'm trying to understand work functions and am working through a paper but keep coming up with the wrong answer. Can anyone point out where I'm going wrong please...

    Wavelength of light incident on surface = 560 nm
    Max speed of ejected electrons = 1.67 x 105 ms-1
    1 eV = 1.602 x 10-19 J

    I'm using 0.5mv2=hf-ø rearranged as ø=hf-0.5mv2

    Putting in the figures above:

    =(6.63 x 10-34) x (1 / (5.6 x 10-19)) - 0.5 (1.67 x 105)2 x 9.109 x 10-31

    = 1.18 x 10-27 - 12.70 x 10-21 = -1.27 x 10-20 J

    I'm sure I'm not meant to come up with a negative answer.

    Many thanks for any assistance you can give.

    Bob
     
  2. jcsd
  3. Apr 14, 2014 #2
    Hi Bob, shouldn't there be a c in there?
     
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