tag:blogger.com,1999:blog-13869903.post8745927240638376758..comments2024-03-28T04:15:44.459-05:00Comments on nanoscale views: The 1993 Stanford physics qualDouglas Natelsonhttp://www.blogger.com/profile/13340091255404229559noreply@blogger.comBlogger10125tag:blogger.com,1999:blog-13869903.post-78143737155094395232019-05-03T13:16:49.262-05:002019-05-03T13:16:49.262-05:00Quals for Nuclear Science and Engineering at Michi...Quals for Nuclear Science and Engineering at Michigan in the 60s were 6 hrs of written and a 2hr oral. The challenging part of the written was determining which problem was contributed by Prof Chihiro Kikuchi (ruby maser developer). It would be something he was working on and he was looking for help. You obviously had to attempt it last.Mike Natelsonhttps://www.blogger.com/profile/11303344299824999211noreply@blogger.comtag:blogger.com,1999:blog-13869903.post-73685818317465751602019-05-02T15:38:51.790-05:002019-05-02T15:38:51.790-05:00That was truly the Golden Age of Bob as a personal...That was truly the Golden Age of Bob as a personality.Peter Armitagehttps://www.blogger.com/profile/11567089164372083820noreply@blogger.comtag:blogger.com,1999:blog-13869903.post-84288583248129819172019-05-02T14:06:23.797-05:002019-05-02T14:06:23.797-05:00Grumpy, the two aspects (students learning while p...Grumpy, the two aspects (students learning while preparing for exams + exams serving some useful diagnostic purpose on the one hand; the exam being a stressful experience for the students on the other) are not necessarily mutually exclusive. <br /><br />Regarding learning from unstructured studying: that might work well for some people, though educationally there is some virtue (I think) in fighting the usual doctoral tendency toward very narrow, specialized focus. <br /><br />I agree that high stakes exams are not necessarily healthy. One reason why I like oral exams more than written quals: Oral exams at least resemble or mimic some aspect of real scientific discourse. In a professional scientific setting, I might actually have to respond to questions and do some calculations or estimates on-the-fly at a chalkboard, and communicate my thinking and the results to someone. In contrast, I've always found timed, closed-book exams to be very artificial instruments that may not be measuring what an evaluator would really want to know.<br />Douglas Natelsonhttps://www.blogger.com/profile/13340091255404229559noreply@blogger.comtag:blogger.com,1999:blog-13869903.post-66771612086056177302019-05-02T08:10:16.146-05:002019-05-02T08:10:16.146-05:00You talk about how these high stakes exams help st...You talk about how these high stakes exams help students learn while crash studying for them. But then you talk about "flashbacks" and being sent on wild goose chase on problems with typos, long calculations, etc.<br /><br />So which one is it?<br /><br />I also had to pass a rigorous set of exams as a grad student and feel like I learned while studying for them. But I'm not sure I learned more than if that time had been used for more unstructured study. And I'm not sure if the trauma of high stakes exams is healthy for some students.Grumpyhttps://www.blogger.com/profile/06238708584935877026noreply@blogger.comtag:blogger.com,1999:blog-13869903.post-20318793598814168902019-05-01T20:57:36.420-05:002019-05-01T20:57:36.420-05:00Dan, I’d mentioned in my original anecdote about t...Dan, I’d mentioned in my original anecdote about this - Laughlin had gotten annoyed and impatient with his faculty colleagues on the qual committee, and had decided to write most of the exam himself. <br /><br />A follow-up: In the aftermath of this problem of multiple typographical mistakes on the exam, they decided to add a couple of students to the qual committee, whose job it was to check over the problems before the test to make sure it was do-able. I ended up in that role for two years.Douglas Natelsonhttps://www.blogger.com/profile/13340091255404229559noreply@blogger.comtag:blogger.com,1999:blog-13869903.post-34954345936791137042019-05-01T17:24:39.064-05:002019-05-01T17:24:39.064-05:00It would not be unusual for each problem to have b...It would not be unusual for each problem to have been crafted by a different member of the faculty (so that Laughlin did not personally have to do all the work of creating the entire exam by himself). I'm not sure if that's the way things were done at Stanford in 1993... but anyway, whichever professor wrote the pot roast question is a kindred spirit.DanMnoreply@blogger.comtag:blogger.com,1999:blog-13869903.post-53343911346160713202019-04-30T08:39:23.584-05:002019-04-30T08:39:23.584-05:00PPP, IIRC you can assume the proton and neutron ar...PPP, IIRC you can assume the proton and neutron are point particles. For order of magnitude, you can treat it as a particle-in-a-3d-box problem, box depth V0, and pick b so that what would be the first excited state has energy 0. Douglas Natelsonhttps://www.blogger.com/profile/13340091255404229559noreply@blogger.comtag:blogger.com,1999:blog-13869903.post-61567528414687668912019-04-29T21:25:36.594-05:002019-04-29T21:25:36.594-05:00Gotcha. By the way, for the QM1 question, part 1, ...Gotcha. By the way, for the QM1 question, part 1, were you expected to have a rough idea of the typical radius of the proton and neutron beforehand? Or was there some other way to estimate the characteristic proton-neutron binding distance?Pizza Perusing Physicisthttps://www.blogger.com/profile/02213655278674258393noreply@blogger.comtag:blogger.com,1999:blog-13869903.post-57274097949320965112019-04-29T21:08:34.640-05:002019-04-29T21:08:34.640-05:00Yes. (Added bonus: the rocket equation in the fi...Yes. (Added bonus: the rocket equation in the first problem is also wrong.). RBL had a brief moment when he wasn’t sure if the problem was analytically solvable in closed form.Douglas Natelsonhttps://www.blogger.com/profile/13340091255404229559noreply@blogger.comtag:blogger.com,1999:blog-13869903.post-88477579610950168972019-04-29T20:31:34.027-05:002019-04-29T20:31:34.027-05:00I recall from your previous post about this exam t...I recall from your previous post about this exam that there was one particular question with a typo (omega where there should have been an omega_0), which Laughlin thought made the question impossible to solve, but which one Russian conformal field theorist said was indeed solvable, though difficult.<br /><br />Is the typo in question on part #2 of the "Quantum Mechanics - II" section? Pizza Perusing Physicisthttps://www.blogger.com/profile/02213655278674258393noreply@blogger.com