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Homework Help: Finding Maximum kinetic energy of ejected electrons

  1. Jun 7, 2012 #1
    1. The problem statement, all variables and given/known data
    So i know the light colour, wavelength, cutoff potential and frequencies. im trying to find the maximum kinetic energy of the ejected electrons(J or eV)
    heres the first set of numbers for the colour of yellow:
    wavelength 578nm(5.78 x 10 to the -7metres). cutoff potential 0.25v. Frequency= 5.19 x 10 to the 14 HZ

    2. Relevant equations
    E= hc/λ


    3. The attempt at a solution
    so i started to think that i was supposed to use the equation e=hc/λ. but it is not getting me the right answer. i think this might be because the "E" is just total energy and not kinetic, but i have no idea what to do. Please help
     
  2. jcsd
  3. Jun 7, 2012 #2

    ehild

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  4. Jun 7, 2012 #3
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