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Homework Help: De broglie wavelength

  1. Jun 10, 2012 #1
    1. The problem statement, all variables and given/known data

    Screenshot2012-06-10at84946PM.png



    3. The attempt at a solution

    I don't see how they got sqrt(1.5/E) I tried it like this

    Screenshot2012-06-10at84925PM.png

    Not the right answer.
     
  2. jcsd
  3. Jun 10, 2012 #2

    cepheid

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    It looks like you took the square root of h/(√2m) when you should have done the exact opposite: you should have squared it. Here's the reason. If:$$\sqrt{1.5} = \frac{h}{\sqrt{2m}}$$then$$1.5 = \frac{h^2}{2m}$$

    I computed h^2/(2mE), and I plugged in a value of E = 1 so that I would get the same numerical answer as they did. I also had Google express it in nm^2 instead of m^2, so that the answer would be the same as theirs:

    Google Calculator link
     
  4. Jun 10, 2012 #3
    cool, i got it now.
     
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