Wednesday, December 5, 2007

Further analysis of exam III

I know you're all dying to know how exam III broke down by question. Probably, you've been lying awake at night wondering what percentage of people answered multiple choice question 3 correctly, what percentage of people chose to solve problem 5, and what the average score on problem 4 was.

Wait no longer. Well, just a little bit longer.

The average was 82.33% (std. dev 23%) overall, which weighted the multiple choice and problems sections equally. The bonus question counted as one multiple choice question. There were 17 A's, 18 B's, 7 C's, and 4 D/F's. Clearly, this thing was too easy. :-)

The problems section had an average of 88.43% (std. dev 25%), while the multiple choice section averaged 72.1% (std. dev 23%). This disparity probably has something to do with the fact that I solved two of the exam problems in class the day before ...

Anyway. Here you are. Clicky-clicky for a larger plot.From this one, you can see more clearly that the problems section of the exam really pushed the average up. The multiple choice alone would have made for a somewhat disappointing result in the end.

Here is where I thought there were some interesting things going on. Question 3 on the multiple choice was by far the 'hardest', followed closely by numbers 5 and 6. Number 5 was on nuclear physics we had only covered days before, but numbers 3 and 6 were both conceptual, as was number 7, the next lowest. Broadly, the conceptual questions seem to cause the most trouble.

For the problems, no one seemed much harder than any other based on average score, but if you look at the number of people choosing to attempt each problem (recall you had to do 2 of 5 problems), then numbers 1 and 4 win in a landslide - the ones I did in class the day before.

Glean from this what you will, don't take it too seriously. I just think its good for me to look at these things and see if I can identify which questions/concepts in particular were troublesome, and whether that's something I can try to correct.

Friday, November 30, 2007

Exam III solutions

Right now, you are still busy taking the exam ... its not so bad, is it?

Here are the solutions, and here is the exams folder to see all 3 exams and solutions.

I should be able to hand back the exams as well as your papers this coming Tuesday in class (in which I will give a lecture on how hard disks and flash memory work).

Tuesday, November 27, 2007

Exam III is this Friday

So. You have an exam on Friday during the recitation period. Since this means you have only 50 minutes to complete the exam, it will be short if nothing else. The following material is fair game (numbers refer to sections in Serway & Faughn):

  • Lenses (23.4-7)
  • Quantum Physics (27.1-3,5,6,8)
  • Atomic Physics (28.1-7,11)
  • Nuclear Physics (29.1-6)
The exam will have a format somewhat like the final exam, though shorter: there will be both problems (like exam II) and multiple choice questions (like exam I).

  • multiple choice questions
    • 50% of the grade
    • approximately 8 questions
    • like the quizzes - some conceptual questions
  • 4 problems given / solve 2
    • 50% of the grade
    • choose to solve 2 of the 4; all have equal weight

You may bring in a formula sheet and a calculator, following the same rules as last time around. Your time will be limited on Friday. Don't be late.

Finally: you will know the results of exam III and your grade going into the final by Thursday of `dead week' (possibly excluding the paper grade ... I don't know yet if I can read 50 of them in a week or not).

Monday, November 26, 2007

Exam II solutions / quiz solutions

Just in time for final exam season, the detailed solutions to Exam II are ready. Note that Exam I and its solution are still there.

Also, at long last, all of the quiz solutions are available.

Papers due tomorrow ...

Just a friendly reminder that your 5 page papers are due tomorrow ...

Sending me a PDF is the preferred form of submission. Other file formats are fine (e.g., MS Word ) if you aren't sure how to generate a PDF. Of course, hard copies are fine too, if you want to go that route.

Tuesday, November 20, 2007

Lab for 20 Nov 2007

Today we will use the known line emission spectrum from Mercury atoms to calibrate a diffraction grating, and then use our calibrated grating to determine the wavelengths of emission from hydrogen atoms.

So basically, we will measure the emission spectrum from hydrogen.

Procedure.

Monday, November 19, 2007

homework deadline extended

If you have not already seen, the homework that was supposed to be due this past Friday is now due tomorrow (Tues) at midnight.

I was getting a lot of questions, which indicated to me we didn't cover a couple of things well enough. We will go over some of the questions in class tomorrow, and hopefully by the end of it you will know how to do all of the problems ...