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Homework Help: Uncertainty principle

  1. Feb 22, 2009 #1
    1. The problem statement, all variables and given/known data

    Using the uncertainty principle find the energy required for the electron to be confined inside the hydrogen atom. Use the radius of the atom 1 x 10^-10 m for Δr. Express your answer in eV, rounded up to the nearest hundredth.

    2. Relevant equations

    x= position in space
    p= momentum (mass)(velocity)
    3. The attempt at a solution

    ok im not sure how Δr (radius) goes into the uncertainty principle, i know how it works and how it shows that it can not be exactly precise but i just dont understant how Δr would fall in the equation

    is it just 1 x 10^-10 m[tex]\geq[/tex]4.14x10^-15 eV/12.56637061?
  2. jcsd
  3. Feb 22, 2009 #2
    delta_r is your delta_x.

    The speed of the electron is not relativistic. (at least I don't remember it to be)
    Use the momentum to get your kinetic energy.
    Then convert units.
  4. Feb 22, 2009 #3
    o ok. and for the momentum. would i just use mass and velocity of an electron?
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