1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Particle in a 3D box (Quantum)

  1. Feb 24, 2012 #1
    1. The problem statement, all variables and given/known data

    What are the degeneracies of the first four energy levels for a particle in a 3D box with a=b=1.5c?

    2. Relevant equations


    For 1st level, the above = 3h2/8m
    For 2nd level, the above = 6h2/8m
    For 3rd level, the above = 9h2/8m
    For 4th level, the above = 11h2/8m

    3. The attempt at a solution

    I think I finally grasped the basis of what the problem wants.

    For the 1st level:

    Exxnynz=(h2/(8m*1) + h2/(8m*1) + h2/8m*(1/1.5))*(1+1+(3/2))

    So E1 1 3/2

    3/2 was obtained because 1/1.5 is 2/3=c because a=b=1=1.5c so c=1/1.5=2/3

    Is this correct? I'm just unsure about the rest of the energy levels. It seems like one can just pick numbers and force it to work so I'm lost on the proper degeneracy.
  2. jcsd
  3. Feb 24, 2012 #2


    User Avatar
    Homework Helper

    Why are you multiplying by (1+1+3/2)? I don't think you've got the idea. The quantum numbers each take on an integer value, and that is why the energy levels are different.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook