Exam 2 post-mortem

I will have the exams graded by Wednesday's class. You can find the exam and partial solutions here. I think we'll probably spend a good deal of that class period going over the exam problems and common misconceptions. It was a hard exam, no question, and we are not in a rush to move on, so we can afford to spend a little time thinking about it.

For now, don't freak out. I'm not going to fail any of you based on a quick glance of the exams, and the partial credit will be generous. It is simply much easier for me to gauge your understanding with very hard problems than very easy ones - if you got everything right, I'd have no way of seeing the limits of what you've learned so far. So, focus on learning something from the exam for now, the grades will be better than you think.

HW3 solutions

Here you are.

HW3 out, HW2 solutions

Here are HW2 solutions. HW3 is now out as well, due Monday 12 Sept.

HW2 / HW1 solutions

HW2 is out, due this coming Friday (not Wednesday, as implied by the calendar).

HW1 solutions are also out.

Answers to the last quiz

Here you go.

HW 6 & 7 solutions

Homework 6 and 7 solutions are now complete.

When it rains it pours: HW6 solutions

Problem 6 does not have a full solution, but based on the general velocity transformation we went over in class you probably got it ...

Anyway: HW6 solutions are out.

Homework 5 solutions

Very late ... but here they are. You'll get your graded HW5 back tomorrow.

Tomorrow, we'll continue with magnetic induction, with a heavy emphasis on the homework problems. Friday, Prof. Harrell will give a lecture on magnetic materials. Monday, we'll finish up induction and Maxwell's equations so we can start ac circuits on Wednesday.

Partial HW4 solution

Here you are.

I will try to finish up a bit more of this tonight yet ...

UPDATE: only number 3 is missing a solution now.

Latest Homework

Some of your problems are here.

Update to HW3 solutions

See here.

I have written a relatively long solution to number 7, which tries to explain the idea behind the coefficients of capacitance. Hopefully this, combined with the short handout from the Purcell book, will make things clearer. If I have some time tonight, I will try to produce a few more examples of calculating coefficients of capacitance and make my own little handout.

I also updated the solution to number 8 (dipole) to try to make the derivation of the potential a bit more clear.

Lastly, HW4 is coming out this evening, and will have problems due on Wednesday and Friday of this week.

Exam I full solutions available.

Here they are. Let me know if you find any typos, or anything which could use further clarification.

You'll get your graded exams back on Monday.

Exam I and its (partial) solution

Find them here. I have solutions for problems 1 and 2, and the first two parts of 4.

I should have full solutions for 3 & 4 this evening, and you will get your exams back on Monday.

HW4 / HW 3 solutions updated

There is a HW4, I just haven't finished it yet. Coming soon, only two problems, due by the end of Friday.

They are still here, but the last problem has been updated a bit. I hope to type up the solution to the coefficients of capacitance problem tomorrow ...

Partial HW3 solutions

Here you go. I haven't typed up number 7 yet, and number 8 is incomplete. The rest are there, probably in more detail than you would like ...

If you didn't get every part of every problem, don't panic. They were very hard problems, and for the most part chosen to illustrate a certain point. If you mostly understand how these problems work out, but didn't quite get every last detail, I'll be happy with that (and partial credit will be generous).

For example, some of the problems (e.g., 5, 6, 8) have a relatively straightforward part followed by a much harder part. If you got the first part reasonably well, you will be fine on the exam, and I'd say you know what you are doing. The harder parts were mainly there to see what you could do, and make you think about things a little more. Again, if you didn't quite get everything, but found yourself thinking carefully about what the problem means, then mission accomplished.

Exam-wise, you can expect stripped-down versions of the easier parts of these problems. I can't stress enough: if you feel like you know what you are doing on the HW problems, but don't quite get them all the way worked out, you have no reason to panic.

On the other hand, panic should set in, a little, if you are not doing the homework (or at least reading the solutions after the fact).

Quiz 2 and its solution

Find them here.

HW2 solutions

They are done, though probably not without errors. (UPDATE: a few stray typos fixed.)

In particular, in problem 11 showing that Coulomb's law is recovered in the limit of small lengths of the rods is stupidly difficult. I think it can be done much more quickly (or at least in many fewer steps) than I took in the solutions, but I wanted to try and make it as clear as I could. Given that it is not trivial to take the small length limits, you will be given a wide berth on that part of the question ...

Now, for HW3: tomorrow we'll set up several of the problems in lecture, I will post some hints tonight. If you did HW2 in a reasonably general way (or at all, really), you will save yourself some work on HW3. In particular, you can re-use the solution for the electric potential due to a line charge and a number of geometric insights.

Updated HW2 solutions

Here you go. All but the last two, I'll try and post those solutions tomorrow.

HW 2 partial solutions

Solutions to Wednesday's problems from HW2.

Grading / Quiz 1

I will have graded things back to you on Friday, sorry for the delay.

Also: quiz 1 and a solution.

Update: having graded the quiz, I'm just going to throw out the first question. Apparently I was a bastard for asking it ... we'll go over the quiz tomorrow in recitation.