Stupid professor question.

Sadly, I am no longer 'with it.' Were I to have an instant messaging account for this class - e.g., so I can answer homework questions in real time - what sort of internets are you using these days? A particular facebook chat application? AIM? Google chat? Since it is no longer 1992, I fear IRC is no longer cool.

Give me some ideas in the comments. I would like to have something more interactive for answering your questions that allows an actual 'conversation' in real time, but I think it only makes sense if it is a system many of you are already using. So, what is your favored online chat client/system?

Exam I results

Well, the results are in. Apparently, you are more clever than anticipated :-)

The overall average was 80.75, with a standard deviation of 15.11, which I was very happy with. Four people answered all questions correctly, well done. Here is the histogram:



Keep in mind that one question is worth 5% (there were 20 questions), so it is somewhat expected that the 'spread' is a bit wide. An average of about 80 means missing only 4 questions. As you can see below, three questions in particular were on average more difficult:


Questions 4, 11, and 12 were most difficult, and I find this somewhat reasonable: question 4 required a subtle application of Gauss' law, and with question 12 it was easy to either misinterpret the question or misapply the power formula. I expected both of these to be harder.

Question 16, another difficult one on average, was basically dimensional analysis in disguise, but nonetheless quite tricky. Question 18 is probably lower due to our covering RC circuits very quickly. Again, I am not surprised that these two seemed more difficult.

Question 11 was, you may now realize, distilled from problem set 4 question 9. It was a difficult question, but one you had the solution to in advance. I did expect it to have a lower average, perhaps not quite as low as it was though.

One very good point: question 17 was right off of the last quiz. On the quiz, only 13% of you answered correctly, compared to 92% on the exam. This is what we like to see!

Anyway: early next week exam solutions will be posted, along with analysis comparing each exam question to a previous similar question from the problem sets or quizzes.

A little bonus for the night owls.

This is the formula sheet you will get tomorrow. If you are still busy making one, you don't need to include any of this.

Homework 5 solutions

Here you go.

Quiz 5 solution

The answers to quiz 5 are now posted in the usual place. For now, there are no detailed solutions. I will try to post those some time Tuesday (and we will go over the solutions in class).

By the way, here are the results:


Obviously question 1 caused some trouble, and we will go over it detail. Note that question 3 was directly from last week's homework, while questions 4 and 5 were straight from the course notes. The solutions for all three of these were available in advance of the quiz.

Exam I details

Exam I is, as you know, scheduled for this Thursday, 21 February. This means that there is no homework due this week, and no Friday quiz. Perhaps the most notable thing about the exam is that relativity is not included.

The exam will cover the following sections in the Serway & Faughn book:

Chapter 15, including Sections 1-6, 9
Chapter 16, including Sections 1-4, 6-10
Chapter 17, including Sections 1-5, 8
Chapter 18, including Sections 1-5

If you are paying more attention to the course notes, it covers the following (referring to the online version):

Chapter 3, excluding Sections 3.6, 3.7
Chapter 4, excluding Sections 4.7, 4.2.2.1
Chapter 5, excluding Sections 5.4.1.1, 5.4.6
Chapter 6 ALL

Whether you pay more attention to the book or the course notes, the list above covers the same topics.

The exam will be multiple choice, and roughly 25 questions long. I suggest studying the end of chapter questions in the notes, as well as your homework and quiz solutions to date.

Roughly half the questions will be conceptual or qualitative (no calculations), and roughly half the questions will involve real, live quantitative answers. With units and everything.

The exam will be in the usual classroom, at the usual time. I will devote the first 15-30 mins of class to answering last-minute questions, after which you will have about 90 minutes for the exam. I expect the exam to take you closer to 60 minutes, but don't want anyone to feel too rushed.

You will want a calculator for the exam.

You can bring in ONE standard 8.5x11 inch sheet of paper front and back (or two sheets front-only), containing any information you like. This could include pictures, formulas, example problems, or even the first few chapters of "The Count of Monte Cristo" in a very small font. Whatever you think might help. You can use both the front and back, typed or written, crayon or pencil, your preference.

One interesting variant is to write from left to right with a red pen, and then turn the page 90 degrees and write over the top of that with a blue pen. If you can then lay your hands on a set of 3-D glasses ... presto, you've doubled your storage density.