Friday, April 4, 2008

Office Hours Monday, misc.

I'll be in my office from 11-2 on Monday for exam-related questions ...

Also, this is interesting ... a lawsuit claiming that students' notes infringe on the professor's copyright. I will not comment directly, there is subtlety involved in this case ...

For the record, my notes are under an open content license. Basically, you can distribute them in whole or in part in any medium you like, without changes. That is, libre, not merely gratis, or free as in "free speech," not "free beer." If you modify the notes, or want to make them into a book, you do need my permission. I doubt you'll break the bank selling them, since they are free online though ...

Tangentially related anecdote follows, with little relation to ph102 ...

I published my Ph.D. thesis under a similar license. I had written several chapters which I though were a good review of my field at the time, and though the best thing would be to make it freely available to anyone who could use it. At the time I felt very strongly that information should be free whenever possible, without creating real or artificial barriers for those who genuinely want to learn something. If your hard work can benefit someone else, that is reason enough to do it. I still feel that way, and that is why nearly everything we do in ph102 is online, for free. When I get to it, anyway.

In my thesis (and in the notes, for that matter), I even carefully remade every figure myself to avoid using any copyrighted material whatsoever- since I had such a hard time finding figures I could freely use, why not save someone else the trouble down the road. It can be tough to find nice explanatory figures for basic things that aren't the Intellectual Property of someone or another. My aim was subversion: if I have to make my own figures anyway, give them away for free, so no one else has to go through the trouble. "Information wants to be free," so the saying goes.

So, a few months after my Ph.D. or so, I was in a conference listening to a talk, and about three slides in was one of my figures in the introduction. Six months later or so, a colleague asked me to help him write a review article. Guess where a good number of the figures came from! This was some years ago, so and things have become outdated a bit, but still every now and again at a conference, I do a double-take, and realize I'm looking at my own pictures ...

That is probably the most satisfying feeling I've had as a scientist thusfar. And that is the idea behind the notes. You're already paying to listen to me - and paying well - there is no reason you should pay a second time, or pay to share what you've learned when you leave here.

On that note, I still have quite some editing to do ...

* Paper and ink still costs money of course. Hats off the the SUPe store, who did a brilliant job, and went out of their way to keep your cost at a bare minimum.
** This post is obviously my own viewpoint, and not that of UA. Disclaimer applies.

Thursday, April 3, 2008

Homework 8 solutions

At long last, the homework 8 solutions are out. Homework 9 solutions and additional problems on lenses are forthcoming ...

Also, since you are dying to know: below is the breakdown of scores by question for the last two homework sets. Click for a larger image.


Wednesday, April 2, 2008

Preemptiveness

Thursday, there will be no lab. Before you become unreasonably distraught, let me explain our alternative plan.

The plan is the following: we finish the lenses material and solve some problems for the first 45 minutes. What we have left is basically to pull together all of the arcane geometry we have used so far and put it into practice - as you did in the lab yesterday. I wasn't joking, we really have done all the math we need for every lens problem you will encounter, the rest is just artwork. Thus, a lot of the first half of class will involve practical examples rather than geometrical proofs.

And then, during the second half of class, there is the preemptiveness. The second half of the class will be entirely devoted to exam II review. Come ready with any and all questions, and I will attempt to answer them for about an hour.

If you don't come with questions, I will invent my own and answer those ... which is usually far less interesting from your point of view.

Tuesday, April 1, 2008

Office hours for Wed 2 April

I have double booked myself a little bit tomorrow ... I have a short meeting from 11:00-11:30, but will be available from 11:30 onward tomorrow for homework questions.

Exam II details

Exam II, as it turns out, is coming up next week - Tuesday, 8 April 2008.

This exam will have no multiple choice questions, it will be entirely problem-based. You will be presented with 8 problems, of which you can choose to solve any 6. You may attempt all 8 problems, but will be graded only on the six that you choose. The topics covered will be magnetism through lenses, thus the following:

  • Magnetism
  • Induction
  • ac Circuits and EM Waves
  • Reflection and Refraction
  • Mirrors
  • Lenses
Additionally, it is likely that there will be one bonus question, worth some to-be-determined fraction of a full question.

Now, consider this: there are six topics, and eight questions. Probability dictates that I will have on average 0.75 questions per topic. Out of your six chosen questions, you are thus likely to encounter 4.5 of the six topics, depending on your choices. Playing the odds, then, one would expect that at least one of the topics above could be safely neglected in preparing for the exam without issue, provided one knew the other five topics sufficiently well.

In other words, you may be better off knowing five of these things very well than six things not so well.

Like last time, you may bring in two sides of an 8.5x11 inch sheet of paper (one sheet front & back, or two sheets front only) with anything you like on them. Those sheet(s) plus a writing implement and calculator are all that you may bring. The exam will take place during the normal class time in the normal place. After answering your last-minute questions, you will have 90 minutes for the exam (though I expect it to take only 60 minutes on average).

More details will follow during the week. Your safest bet is to study the quiz and homework solutions, as well as the example problems in the notes - the exam questions will be easier than the homework (by far), but harder than the quizzes. The solutions to homeworks 8 and 9 will be out by Thursday.

Preliminary lenses notes

The lenses notes are not quite yet complete ... but I hope to have something more or less finished by class time on Thursday.

Right now, I have a derivation of the image properties of spherical and flat refracting surfaces, and the basic equations for spherical lenses. By Thursday, the rest of the material should be there along with some practice problems.

You can find what I have completed here.

Monday, March 31, 2008

Lab for 1 April 08

Here you go. We will investigate various lenses.