Thursday, November 19, 2009

What we covered today / what comes next

Today, what I basically derived was the Drude model of conductivity (or from an alternate viewpoint, the complex dielectric function). Griffiths covers essentially the same material in Ch. 9, treating the problem from a dielectric-centric viewpoint. The Feynman Lectures (vol II) also does a great job of covering the same material, in much the same way that we started today (i.e., from harmonically-oscillating charges). I would suggest reading Feynman, then Griffiths if you are curious. Follow that with Jackson Ch. 7 (link below) if you're really excited.

Here are a couple links you might find useful, if you are interested in going through what we did today a less brutal pace:
Anyway: now we know why metals are shiny, and insulators are mostly transparent.

This brings up a question: we have one more recitation (Fri) which will be devoted to the RFID project, and one more lecture (Mon). What do you want to hear for your last lecture in PH126?

Anything you want, within reason and physics-related (if tangentially), I'll do my best. Leave your suggestions in the comments.

Friday, November 13, 2009

Next homework

Here's the exam you just took. It is also your next homework, due 20 Nov 2009.

Recall that you have an outstanding homework at the moment. It is OK if you turn that in on Monday.

Graduate research competition!

Upcoming event: see what our grad students are up to, and what you could get involved in.

Exam formula sheet

Here it is. Subject to some proofreading ...

Friday's exam

You're ready. Get some sleep.

If you don't believe me, and want to cram anyway, I'd spend some time on Ch. 7, sections 2&3 in Griffiths, and then probably review the sections on Maxwell's equations (sans vector potential).

You will be rewarded if you can quickly recognize what to do with Maxwell's equations when (for instance) given an E field. You will also be rewarded if you have subjugated div, grad, and curl in spherical coordinates (formulas given).

Finally, you will be rewarded with bonus points if you remember what I said about tensors on Wednesday. Specifically, conductivity tensors.

PS - If you are unsure what a question means, or how to go about it tomorrow, don't hesitate to ask. More than likely, I will be willing to clarify the problem a bit or give you a hint to get you started. Also, show and turn in all your work, even if you think it illegible or unimportant. Partial credit is key.

Wednesday, November 11, 2009

Notes for today's lecture

It won't be on the exam, but if you are curious to go through today's material on fluid dynamics at a bit more leisurely pace, I've written up some notes.

UPDATE: I did some cleaning up of the notes. I added quite a bit on fluid rotation (like what curve describes the shape of water going through a drain), and also added a few examples. Specifically, I showed how the Hall effect (current flow in the presence of a magnetic field) requires a tensor conductivity, and treated the case of steady flow through a cylindrical pipe. The latter is a rare example of an analytical solution to the Navier-Stokes equations (given a good number of reasonable assumptions), and quite practical.

The updated notes are in the same location linked above.

No, it is still not going to be on the final, it is just cool. ;-)

Exam III

As you are probably aware, exam III is this Friday. There will be five problems, you must solve any two. The topics are
  • ac circuits
  • relativity
  • induction
  • Maxwell's equations / EM waves
Obviously, one of these sections will have two problems, the others a single problem. Here's what you might want to study/reread before the exam:
  • ac circuits - my PH102 notes
  • relativity - PH102 notes, Griffiths 12.1 (all) and 12.3.1-2
  • induction - PH102 notes, Griffiths 7.2
  • Maxwell - Griffiths 7.3, 8.1, 9.2.1
The corresponding example problems in Griffiths and end-of-chapter problems in my PH102 notes are particularly worth reading through.

This is assuming that you have already read the relevant homework solutions on these topics, which are also helpful. The exam problems will not be as difficult as the usual homework problems, however.

Monday, November 9, 2009