8.021 Class Home

8.021 Physics II

Fall 2010

Instructor: Gabriella Sciolla

TAs: David Liu, William Eric Uspal

Lecture: MTW 10-11 or 11-12 (26-302)
Recitations : Thu 10-11 or 11-12 (26-302)
Weekly Exams: Fri 11-12 (4-370)
Prof. Sciolla's office hours: Wed 12:00-2:00 (26-443)
TA's office hours: Wed 4-5(David); Thu 1-3 (Will), Thu 3-4 (David) (8-310)

Class information :

Very important: please read the archived announcement below labeled "Important information about 8.021" BEFORE signing up for this class. Thanks.

Announcements

paper for class tomorrow

I promised that math would be lighter than last time. Here's a paper on photonic structures in nature, with some colorful pictures:

http://m-newton.ex.ac.uk/research/emag/pubs/pdf/nature01941.pdf

Announced on 07 December 2010 10:24 p.m. by William Eric Uspal

MP grade updated in Stellar

"Mastering Physics" = your score, up to 1200 points; worth the 18% of your final course grade assigned to MP in the syllabus

"Mastering Physics Extra Points" = any points you gained beyond 1200; worth extra credit for the final grade beyond the 18% assigned to MP (this applies to a handful of you)

Announced on 06 December 2010 12:38 p.m. by William Eric Uspal

Minor inconsistency in grading has been fixed

Dear Students,
it was brought to my attention that there was a minor inconsistency in the
grading scheme. Initially, 2 points were assigned to each psets and 11 psets were foreseen. Instead, due to MIT rules, pset #12 has been cancelled.
To make up for this, I have increased the weight of each pset from 2.0 to 2.2
points.

Announced on 04 December 2010 7:44 p.m. by Gabriella Sciolla

Note about Exam Problem 3, parts (e) and (f) solution

Hi,

If you're extremely observant, you may have noticed a discrepancy between u_tot in part (e), the electromagnetic energy density in the capacitor, and part (f), where I found the capacitor energy U_c by the familiar equation U_c = Q(t)^2/2C. Namely: If you integrate only the *first* term in part (e), you already have my answer for (f). Why should this be?

It's because U_c = Q^2/2C is an *electrostatic* formula, and implicitly I made a quasistatic assumption in (f) in using this with Q = Q(t). If you squint at the second term in my answer to (e), you can see that it's actually proportional to I(t)^2. I think this must be the self-inductance of the parallel plate setup, which was not included in the original circuit diagram.

However, this shouldn't affect your grade. If you used U = Q(t)^2/2C in part (f), I gave you full credit. If you used the u_tot from part (e), I gave you credit, with a deduction if you neglected that you need to integrate the spatially dependent term.

Announced on 04 December 2010 1:50 p.m. by William Eric Uspal

How to determine your own grade - clarification

I received a LOT of emails from you asking me to check the actual grade for you. Please follow the instructions below and you will be able to answer the question yourself.
The gradebook shows you three numbers to summarize your performance. See the line labeled Cumulative Score:
CUMULATIVE SCORE 62.69 / 107.50 = 58.32%

1) the actual sum of all the points you have accumulated (62.69)
2) the total number of points available (107.5)
3) the ratio between the 1) and 2) representing your % score (58.32%)

What is your actual score? Start from the number of actual points (62.69)
and subtract the scores relative to the lowest pset and lowest exam.
For example: you scored 15% on pset #3 and 20% on exam 4. Each pset is worth 2 points and each exam is worth 6 points.
Your actual score is: 62.69-2*15%-6*20%=62.69-0.3-1.2%=61.19.

To translate your score into a grade see table in L01.pdf posted online.

Best, Prof. Sciolla

Announced on 04 December 2010 8:02 a.m. by Gabriella Sciolla

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