Suppose you are given three capacitors consisting of aluminum discs configured as in the figure above. You put equal amounts of positive charge on the top discs of each of the three sets and corresponding amounts of negative charge on the bottom discs. If you were to measure the electric fields between the discs, which set would give you the highest value? Which one the lowest? How about the voltages?

Electronic flashes in cameras flash when a capacitor is discharged through a material that produces light energy when electric charge passes through it. This energy comes from a battery inside the flash unit.

Estimate the capacitance of the capacitor used to store the energy. (hint: Assume that the flash gives you the same amount of light as a 500 watt bulb that is turned on for a 60th of a second).

A fresh "D cell" battery can provide about 5000 J of electrical energy before it must be discarded. Estimate the number of coulombs that must pass through it during it's lifetime.

The voltage across a capacitor is given by the formula V=Q/C, where Q is usually called "the charge on the capacitor." Where is this charge in a capacitor? Does the capacitor really have a net charge? If two capacitors are connected together is the charge on one the same as on the other?

You and a close friend stand facing each other. You are as close as you can get without actually touching. If a wire is attached to each of you, you can act as the two conductors in a capacitor. Estimate the capacitance of this "human capacitor".

Contour maps like the one to the right show equally spaced lines of constant elevation at the Earth's surface. Please explain in what sense they are "equally spaced." Also, please explain in what sense these lines could be called gravitational equipotentials.

Estimate the total charge that passes through a lightbulb in one second.