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Homework Help: {Uncertainty Principal} Uncertainty in position and wave-vector

  1. Apr 22, 2008 #1
    A Wave packet is described by

    [tex]\Psi[/tex](x)= sin [tex]\frac{kx}{x}[/tex]

    Make reasonable estimates of the uncertainty in position and wavevector and show that this function obeys the uncertainty priciple

    [tex]\Delta[/tex]x[tex]\Delta[/tex]k>1

    solutionish...

    sin [tex]\frac{kx}{x}[/tex] = sin ([tex]\pm[/tex][tex]\Delta[/tex]x[tex]\Delta[/tex]k) = 0

    hence [tex]\Delta[/tex]x must = some interger of [tex]\pi[/tex]...?

    this is about where i get lost don't know if i'm going in the right direction!?
     
  2. jcsd
  3. Apr 22, 2008 #2
    isn't [tex]\sin{\frac{kx}{x}}=\sin{k}[/tex]? do you mean [tex]{\frac{\sin{kx}}{x}}[/tex] instead?
     
  4. Apr 22, 2008 #3
    yeah ta!
     
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