Wednesday, July 11, 2012

Wednesday's lab

is all about capacitors. We will start to discuss capacitors in Wednesday's lecture before the lab, and use the lab period to verify some of the things we'll discuss.

To be perfectly honest, it is a fairly simple little lab that is as much intended to get you used to operating electrical equipment as it is to prove various things about capacitors. You won't really have to apply the uncertainty analysis you learned on Monday just yet either, but that will come back soon enough. In light of this, take Wednesday as an opportunity to do a relatively simple procedure carefully and really get the hang of connecting electrical components and wiring things up. You can also take advantage of the lab time to ask the TAs questions about homework or lecture material.

In Thursday's lab we will start to learn about circuits. It will also be relatively simple in principle, but the explanations for what you will observe will be more subtle. Paying attention on Wednesday and getting used to wiring things up will pay off on Thursday.

3 comments:

Anonymous said...

On a bit of a side note, I'm looking over the "Summer 2009" HW solutions for "Problem Set 2: Electrostatics" and I notice you noted that #1 & #5 are "..probably not too difficult for exam, but close.."--What does that mean exactly? Are you implying that they are good exam questions but toned down?

The reason I think it is relevant (with it being from summer 09) is because #5 is almost exactly like one of our questions from our own recently just turned in hw (set 2)..and #1 looks similar to problems we've worked as well.

Anonymous said...

Dr. leclair, I noticed that exam 1 from summer 2010 is considerably different from the first exam in summer 2009. which will ours be most similar to?

pleclair said...

#1 - I am implying that those are excellent exam questions, but that the calculations involved might be a bit too tedious. I would be likely to ask something similar on an exam, but toned down slightly (say, for #1 make it a line of charges instead or something, or for #5 make it more like your HW problem with like charges and no external field). Excellent questions to study.

You will find as the course goes on a lot of questions I previously used look very similar to your HW. There are two reasons for this: (1) when you have the same small set of topics, the questions can only be so different really, (2) when you come up with a neat problem you like and thought about a lot, it is much easier to 'tweak' it a bit than to try and come up with something totally new. That's a good reason to study old HW and exams - there are only so many ways I can ask questions about this stuff, and only so many ways I like to do it. I'm likely to reuse the same ideas, if not the exact same questions. Similarly, a lot of example problems in the textbook will look similar, only so many ways to ask tractable problems on this stuff.

#2 - For the summer 09 exam, I tried to do multiple choice to make things easier. It was a disaster, and I've since found that you all do much better on problem-based exams with partial credit (though it is a lot more work to grade). I can expand on why I think this is if you ask in class ... Your exam will be like the 2010 version, not the 2009 version.