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--- classes:2009:fall:phys4101.001:q_a_1219 [2009/12/18 20:36] – x500_hakim011
+++ classes:2009:fall:phys4101.001:q_a_1219 [2009/12/19 17:26] (current) – x500_sohnx020
@@ Line 42: / Line 42: @@
 ====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)===
@@ Line 130: / Line 130: @@
 ====The Doctor 12/18====
 On the discussion problem solutions, the first method used to calculate the parts of the matrix doesn't show how to get the off axis parts.  Which way is this done?  Or did I just miss something in the solutions?  I know I can use the second way as well, but I'm curious as to the first method.
+===The Doctor 12/18===
+Nevermind, I got it.  You just need to need use Psi 5 and Psi 6 instead of Psi 5 for both.
 ====Blackbox 12/18====
 It's hard to understand the solution #3 of Quiz3.
@@ Line 155: / Line 159: @@
 Q=x(∂r/∂x)∂/∂r+y(∂r/∂y)∂/∂r+z(∂r/∂z)∂/∂r
+====Schrödinger's Dog 12/18====
+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====
+In equation 2.123 on page 72, why does the right hand side go to zero?
+===The Doctor 12/18===
+As he said it's a sliver with infinitely small width and finite height.  If it was infinite height the area would still have to be taken into account, but it's not in this case.
+====Schrödinger's Dog 12/18====
+Hey, Cody and Jessica, guess who :P.
 ====Andromeda====
 I seem to have forgotten this, how do you do 5.b in the final practice test?
+===The Doctor 12/18===
+Someone correct me if I'm wrong, but I believe you're just expecting plus and minus hbar as your possible values and you just normalize the a and b elements of the spinor to give you the probability of each.
+==The Doctor 12/18==
+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 ====
+Is anyone else embarrassed for not getting question 3 right on quiz 4 after seeing the solution? It seemed incredibly difficult when taking the exam, but it seem so simple redoing it... Also, I think the practice exam look deceptively easy. I can work these solutions out on the spot without referencing the book or anything, but I have the feeling that the exam questions are going to be much harder... or at least conceptually challenging. My problem on the exams (and the homework, for that matter) has always been interpreting the problem correctly. If given enough time I think I can solve just about anything.
+====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?
+===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.
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