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Homework Help: Help with the Heisenberg uncertainty principle

  1. Sep 29, 2008 #1
    Today I was assigned a question (that is due tomorrow) and I currenlty have very little idea how to solve it... Any help to get me started here would be greatly appreciated.
    1. Use the uncertainty principle to estimate the uncertainty in energy of a proton confined to a nucleus 1.0 x 10^-14m in diameter.

    Here are the equations we were given
    2. (delta x)(delta p) >= h/2pi
    (delta E)(delta t) >= h/2pi

    To try and solve it I wasn't really sure where to start because we werent given the uncertainty in time or the uncertainty in momentum so I am not sure how I can make the transition to energy :grumpy:

    Any help will be greatly appreciated. I do not need someone to solve this for me, please just point me in the right direction so I can learn the material.
  2. jcsd
  3. Sep 29, 2008 #2
    momentum is proportional to velocity which is distance/time

  4. Sep 29, 2008 #3
    How would I figure out the uncertainty in for delta x? I am given that a nucleus is 1.0 x 10^-14m in diameter but I am unsure if the uncertainty would be that whole value or what it is.
  5. Sep 29, 2008 #4
    well you know it isnt outside the nucleus.

    where exactly inside the nucleus would you expect it to be?
  6. Sep 29, 2008 #5
    I solved it, just thought I should respond so that people didnt continue to post. Incase anyone has trouble with this type of the question in the future:
    I used (delta x)(delta p)=h/(4pi)
    then using the value of (delta p) found the (delta v)
    then using the (delta v) was able to find (delta E) using a variation of the EK=1/2mv^2 formula, (delta E)=1/2m(delta v)^2. I hope my misery helps someone lol...
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