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Homework Help: DeBroglie wavelength considering relativistic effects

  1. Mar 22, 2006 #1
    "Electrons are accelerated by a potential of 350kV in an electron microscope. Calculate the de Broglie wavelength of those electrons taling relativistic effects into account"


    I attempted the following:

    W = W(kin) = 350keV

    now

    [tex]W(kin)= (1-gamma)mc^2 [/tex]

    so, now one could solve for gamma and find the velocity of the particle.


    afterwards [tex] p=m*v=h/lambda [/tex]

    HOWEVER: I get a negative result in a root when I try to solve for v. Therefore I think that my energy formula must be wrong (I already excluded calculation errors). Can anyone see it?
     
  2. jcsd
  3. Mar 22, 2006 #2

    nrqed

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    It's [itex] (\gamma -1) m c^2 [/itex] (the gamma factor is always larger or equal to 1)


    Patrick
     
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