Please answer this question in physics

  • As many already know, studying for the physics GRE and getting accepted into a graduate program is not the final hurdle in your physics career.
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meegal90
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Joined: Wed Jun 06, 2012 3:55 am

Please answer this question in physics

Postby meegal90 » Wed Jun 06, 2012 4:01 am

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Last edited by meegal90 on Fri Jun 08, 2012 5:00 am, edited 1 time in total.

microacg
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Joined: Sat Mar 03, 2012 2:06 pm

Re: Please answer this question in physics

Postby microacg » Wed Jun 06, 2012 6:18 am

Have you tried the question yet?

meegal90
Posts: 5
Joined: Wed Jun 06, 2012 3:55 am

Re: Please answer this question in physics

Postby meegal90 » Wed Jun 06, 2012 10:23 am

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Last edited by meegal90 on Fri Jun 08, 2012 5:00 am, edited 1 time in total.

bfollinprm
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Re: Please answer this question in physics

Postby bfollinprm » Wed Jun 06, 2012 4:11 pm

meegal90 wrote:Is the answer is 3 fold degenerate with nx,ny and nz values 1,1,3 respectively??


No, and, err..no. So the idea of degeneracy is to count the number of possible combinations of quantum numbers that gives the appropriate energy, with the rule that the n's are quantized as integers. So saying that nx = ny = 1, and nz = 3 is the answer isn't right--that could be one of the ways, but certainly not all; if that's allowed, so is nx = nz = 1, and ny = 3.

Also, you're in a 2-D well, so there are only 2 quantum numbers, not 3 (which is fortunate, because otherwise this particular energy state would be impossible). Wikipedia states E = (hk)^2/(8mPi^2), with k^2 = k(dot)k = pi^2/a^2(nx^2+ny^2).http://en.wikipedia.org/wiki/Particle_in_a_box#Higher-dimensional_boxes

So, that should be enough to answer the question, which is really how many ways can you have nx^2 + ny^2 = 25, since everything else is just a constant, the same on both sides, which allows you to cancel.

meegal90
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Joined: Wed Jun 06, 2012 3:55 am

Re: Please answer this question in physics

Postby meegal90 » Thu Jun 07, 2012 8:25 am

So the answer is two fold degenerate since quantum numbers can take the value nx=3,ny=4 or nx=4,ny=3. Am i right??

kangaroo
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Re: Please answer this question in physics

Postby kangaroo » Thu Jun 07, 2012 10:34 am

Your college should investigate you for academic dishonesty.

meegal90
Posts: 5
Joined: Wed Jun 06, 2012 3:55 am

Re: Please answer this question in physics

Postby meegal90 » Thu Jun 07, 2012 11:29 pm

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Last edited by meegal90 on Fri Jun 08, 2012 5:01 am, edited 1 time in total.

kangaroo
Posts: 130
Joined: Fri Jan 13, 2012 5:31 am

Re: Please answer this question in physics

Postby kangaroo » Fri Jun 08, 2012 2:31 am

meegal90 wrote:Give the right answer please...


Seriously, the nerve?! No one here owes you an answer, and you don't even attempt to show a proper attempt at the question. Just f*** off, and stop spamming the physics community here, which is meant to be GRE related, and not to help spineless leeches like you.




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