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classes:2009:fall:phys4101.001:q_a_1219

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classes:2009:fall:phys4101.001:q_a_1219 [2009/12/18 23:42] – olmschenkclasses:2009:fall:phys4101.001:q_a_1219 [2009/12/19 17:26] (current) – x500_sohnx020
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 ====The Doctor 12/16==== ====The Doctor 12/16====
-Was it said whether the most recent chapters would be more of the material on the final or not?  It the final based mostly on the more recent things, or it evenly spread between everything so far?or+Was it said whether the most recent chapters would be more of the material on the final or not?  It the final based mostly on the more recent things, or it evenly spread between everything so far? or...?
  
 ===The Esquire 12/16 (age of the forgotten)=== ===The Esquire 12/16 (age of the forgotten)===
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 How does Griffths go from the 1st to the 2nd equation in equation 7.23 on page 301?  How does Griffths go from the 1st to the 2nd equation in equation 7.23 on page 301? 
  
 +===The Doctor 12/18===
 +Consider the first term of the 2nd equation:
 +<math>(r_1+r_2)</math>
 +Square it and you get
 +<math>(r_1^2+r_2^2+2 r_1 r_2)</math>
 +So if you take the square root of that you get back to where you started.  This square root is what happens in going from the first to the second equation for the first term, but the idea is the same for the second one as well.
  
 ====Schrödinger's Dog 12/18==== ====Schrödinger's Dog 12/18====
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 Unless this doesn't work for <math> S_y </math>. Unless this doesn't work for <math> S_y </math>.
  
 +== Zeno 12/19 12AM ==
 +Pages 174 and 175 go over the solution strategy for S_x which is very similar for S_y. For part a, did anyone else get plus and minus h-bar over 2 with probabilities 5/9 and 4/9? Good luck tomorrow (or today) everybody.
  
 ==== Zeno 12/18 11PM ==== ==== Zeno 12/18 11PM ====
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 ====The Doctor 12/18==== ====The Doctor 12/18====
 What are people doing for the 4th question on the practice final?  Is it actually really easy or am I'm thinking about this wrong? What are people doing for the 4th question on the practice final?  Is it actually really easy or am I'm thinking about this wrong?
 +
 +===Anaximenes - 00:40 - 12/19/09===
 +Near as I can tell, it should just be <math>\psi_a (x_1)\psi_b (x_2) - \psi_b (x_1)\psi_a (x_2)</math>.  Is that what you were thinking?  Or do you think the problem wants us to multiply in the spin wavefunction?  E.g., <math>\psi_a (x_1)\psi_b (x_2)[\chi_+ (x_1) \chi_- (x_2) - \chi_- (x_1) \chi_+ (x_2)]</math>?  (I'm not especially certain that expression actually means anything.)
 +
 +====Esquire 12/19 (Age of Final)====
 +What did you guys think about the final? I thought it wasn't terrible, thought I didn't get a few things.
 +
 +===Anaximenes - 15:30 - 12/19/09===
 +I thought it was good.  All of it was reasonable (not incredibly easy or difficult), but it covered a wide range of topics.  What did everyone put for #6?  Those open-ended questions always take me the longest.  I described how the graph shows the Zeeman effect is dominant at high <math>\beta</math> but Fine Structure is dominant at low <math>\beta</math>; that of the 8 energy eigenvalues, 4 had simultaneous eigenstates of j, <math>j_z</math>, <math>m_l</math>, and <math>m_s</math>; and that the two middle eigenvalues have <math>\displaystyle \lim_{\beta \rightarrow \infty} \lambda = -3\gamma</math> (i.e., they become degenerate).
 +
 +=== Blackbox 12/19 ===
 +I'm just wondering whether these kinds of questions and answers or opinions about the exams are also counted in the total.
  
 ====Links==== ====Links====
classes/2009/fall/phys4101.001/q_a_1219.1261201335.txt.gz · Last modified: 2009/12/18 23:42 by olmschenk

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