Next week's reading / Today's recitation

Next week, we'll be covering Ch. 25, "Electric Potential." Some of this will be familiar already (I hope) since we already talked about the work and potential energy required to build various charge configurations.

Today in recitation we'll use Gauss' law to find the force on a thin sheet of charge (more useful than it sounds). From this result, next week we will derive the energy stored in the electric field, and can start to talk about capacitors and real, live circuits.

After which there is of course a quiz.

If you have not already, I again suggest reading the quick quizzes in Ch. 24 in preparation for the quiz. The quiz is solely on Gauss' law, and requires no serious calculations.

As an aside, you might notice from the reading/lecture that there are really only three easy applications of Gauss' law in the way we are studying it:

1. long linear charges
2. spherically-symmetric charges
3. flat plates of charge

Anything beyond these three is usually either a) a trivial extension of one of the above, b) hideously difficult, or c) involves a stupid symmetry trick, but is of questionable utility. We'll do some examples of a and c tomorrow ... examples falling under category b are usually best solved by other methods.