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Homework Help: Please help! Ground State Energy Problem!

  1. Apr 19, 2009 #1
    1. The problem statement, all variables and given/known data

    The particle in a box model is often used to make rough estimates of ground state energies. Suppose that you have a neutron confined to a one-dimensional box of length equal say 1 x 10^-14m. What is the ground state energy of the confined neutron?

    answer in MeV?

    2. Relevant equations

    En = h^2/8mL^2

    3. The attempt at a solution

    I am getting the wrong answer... I am getting:

    (6.626e-34)^2/((8)(1.675e-27)(1e-14)^2) = 3.28e-13

    That is wrong... anyone?
  2. jcsd
  3. Apr 19, 2009 #2


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    Gold Member

    Do you know the actual answer? Are you expressing it in MeV?
  4. Apr 19, 2009 #3
    I don't have the answer, I have to submit electronically and I am getting it wrong.

    I'm not sure actually....that was my issue...maybe I am not converting to MeV. Any ideas?
  5. Apr 19, 2009 #4


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    Gold Member

    Remember, planck's constant that you applied is in J*S. Thus your units is in joules. Convert your answer to MeV :)
  6. Apr 19, 2009 #5
    Well, I multiplied my answer by 6.24e12 because 1J = 6.24e12MeV, and I got 2.05, that is still wrong.
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