1: (24-23) Practice with work, potential energy, and electric potential. Very much plug and chug – low difficulty. Overall, I minimize the straight plug and chug content on an exam. However, I do put a little in … and this would be a candidate for that.

2: (24-9) Similar to above, but potential of a distribution of discrete charges. moderate difficulty

3: (24-18) Nice, moderately difficult problem involving the calculation of the potential of a distribution of discrete charges. Practice with symmetry. Practice with thinking about a limiting case. I could turn this into a good moderate difficulty exam problem.

4: (24-19) Very similar to problem 3. Now you see the difference a sign change makes. If stand alone, I think this is harder than 3 because you must pay attention to the sign of the charge and know what that means.

5: (24-29) Electric potential energy to kinetic energy conversion problem. This would be difficult if given on an exam because the potential changes as a function of position … which means you must set up and evaluate an integral to solve this problem.

6: and 7: (24-31 and 24-35) Very straightforward practice on equipotential surfaces and deriving the electric field from the potential via the "gradient".

8: and 9: (24-61 and 24-62) How does a Geiger counter work? If you work with "hot" biological compounds (those labeled with a radioactive isotope) you should be interested. 24-61 is difficult for this class … would be very difficult (but fair enough) for an exam. It involves using Gauss’s Law to get the electric field and then evaluating a work integral to get the potential … also involves superposition of the potentials of the two conductors. 24-62 uses the results of 24-61 in a Geiger counter application. This one is also difficult, but not at the level of 24-61.

10: for interest, not exam preparation. This is more appropriate for physics majors but some of you deep thinkers might enjoy it. Doing it should lead to a greater appreciation of Gauss’s Law and how it works.