FA11 E&M II Paper Assignment

Deadlines: HW #6 (Due Oct 12) asks you to pick a paper. HW #7 (Due Oct 19) will ask you to read it and write a summary/review. I prefer if you plan to FINISH it by this time (Oct 19), but you'll be allowed up to the next week, Oct 26, to submit it, if you want/need the extra time.

What is this assignment? We are asking you to read a journal article about anything related to E&M, and write up a brief (less than 1 page) summary and review. It is not meant to be an odious task, and the grading will be generous - but I want to strongly encourage you to take the time and effort to try to read a journal article. It's very different from reading a text. Treat this as roughly equivalent in your time and effort to a particularly long, hard homework problem.

Where do I find articles? I strongly suggest you pick an article from the American Journal of Physics. AJP is probably the most accessible physics journal for undergrads - articles can certainly be hard, but I'm willing to bet you'll get something useful out of them. (This journal is certainly more readable than, say, the harder core Physical Review journals)

What article should I read? It's your call! Ideas follow. Griffiths references papers (Probably 90% of them from AJP) in footnotes and problems throughout the text, but especially in the second half. So, find a place that you were curious about, pick that article, and read it. Or just go to the AJP website and browse/search for topics that interest you (think of useful search terms, "electromagnetism" will already get you started, but feel free to hone in on something you're interested in - history, magnetic monopoles, superconductors, dipoles, whatever!) See below for suggestions (Charlie has put some effort into guiding you to some interesting articles)

What will I have to do and write up? I recommend finding an article, and make a "casual" first pass. Don't worry about the details, try to get the big picture, follow the main ideas. If you feel like the paper is still what you want - go back and reread it, and try to work out some of those details. Authors skip a lot of algebra- maybe try to reproduce/derive their equations. It will be at least as hard as a challenging homework problem, especially if you really try to work through it. Give it a serious effort, this is an important step towards moving beyond the undergraduate learning frame. In the end, we're going to ask you to summarize the paper, tell us what you learned, how hard was it, how well written was it, what did you take away? This will include both a summary of content, and a review (basically - should we go and read it?)

How do I interpret Griffiths references? Here's an example of Griffiths referencing style (I picked a recent paper I found that REALLY surprised me. I thought I understood electrostatics and conductors, this result was quite counterintuitive and cool)

M. Levin and S. Johnson , Am. J. Phys 79, 843, (2011)

Authors are listed first, then the journal. The Bold number is the "volume", which for AJP pretty much tells you the year. The next number (843 in this example) is the page number. (AJP continues numbering throughout the year, so you can get to pretty big page numbers) The last number in parentheses is the year it was published. At the AJP website, you can "browse" through volumes, or you can "search" for authors and/or titles. I like to include the full title of the article too, but Griffiths doesn't do that to save space.


Example ideas: (But feel free to browse AJP for yourself)

Charlie Baily has produced a list of AJP papers he has read this term that he thought would be of interest to you.

Alternatively, I list below page numbers from Griffiths where I spotted references to papers, but I'm sure there are plently that I've missed. Keep your eyes open as you're reading. I haven't read all of these papers yet, but here's my quick summary based on Griffiths footnotes:

In Chapter 7
Griffiths page 288: (we talked about this in class- what happens on the wall of a conductor to keep the E field so beautifully uniform inside?),
p. 289: (the Drude model of Ohm's law, also mentioned in class),
293: (how do batteries work? Apparently, it is NOT little fairies transporting electrons after all),
295: (If B fields do no work, how can you lift iron with a magnet?),
298: (You can compute eddy currents!) ,
304 (More on that jumping ring demo, really working it out),
308 (Finding the induced E field outside a long wire with changing current. It's an example in Griffiths and looks so simple, but it's just full of puzzles and challenges!),
309 (What's the E field inside a coaxial cable? We use the EMF in a homework problem on set #5, but that's different than the field itself!), 323 (History of the displacement current. Maxwell still believed in the ether, and didn't know about electrons, when he "invented" his additional contribution to Ampere's law. The history is quite interesting!)
328 (See the two problems on this page, here are some papers about how magnetic monopoles would enter Maxwell's equations),
334 (We had a couple of homework problems to find resistance of funny shaped resistors. In Freshman textbooks, ther is a "canonical" homework that I bet you also did, and the solution you found (and that the textbook "approved" is deeply flawed! Here's a nice paper explaining what was wrong!)
337) (Problem 7.50 was on our set #3, the one that bothered some of you because voltage from "a to b" was different on different paths! Here's a paper about that. At the bottom of the page is something different - for Problem 7.51 which talks about "perfectly conducting" loops being moved in magnetic fields, and lastly
339 (See question 7.55, and papers about what really defines "magnetostatics")

In Chapter 8: p. 358 (Problem 8.6 looks so simple - just a simple capacitor and uniform B field - but there is some subtle physics here, when you compute the "momentum" present in this system and find it doesn't seem to be zero!),
p. 359 (A paradox from Feynman, that looks like violation of conservation of angular momentum at first glance),
p. 361 (more on the previous issues...)

In Ch 9: pp. 376 (Some history of Maxwell, and a discussion of spherical, rather than plane, wave)
p. 383 (how can anything really be transparent, what's the physics behind that?)
p. 393 (Papers pointing out a "white lie" in a derivation we will make and use in class)
p. 399 (what do you mean phase velocity can be GREATER than the speed of light in many cases?)
p. 414 (A classical example that looks a lot like quantum tunneling!)

And that's just through Chapter 9! There were more from the 1st part of the book, (and plenty more coming, but it's more fun to read a paper on something you already know something about..)