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Homework Help: Electric Potential and Wave Nature of Matter

  1. Feb 7, 2013 #1
    1. The problem statement, all variables and given/known data
    An electric potential difference accelerates electrons from rest position towards a screen.
    Just before striking the screen, the electrons have a wavelength of 1.0*10^-11 m
    Find the electric potential difference.

    2. Relevant equations


    3. The attempt at a solution

    v=72777167.95 m/s

    0.5(9.11*10^-31)(72777167.95)^2 - 0.5(9.11*10^-31)(0)^2 = eΔV
    ΔV=0.5(9.11*10^-31)(72777167.95)^2 / e
    ΔV=15078.51948 V

    Is this correct? (other than significant digits)
    Last edited: Feb 7, 2013
  2. jcsd
  3. Feb 7, 2013 #2


    Staff: Mentor

    Once again your v=(6.63*10^-34) / ( (1.0*10^-11) * (9.11*10^-31) )equation needs some parens

    and your v result needs to be significant figure adjusted to be 7.28 x 10^7 m/s

    similarly for the delta v result.

    Again the physics looks right but someone at PF needs to second it for me.
  4. Feb 7, 2013 #3

    the question wasn't asking for velocity so i didn't round it in order to get a more accurate result for electric potential difference
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