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Two positive point charges are infinitely far apart. Is it possible, using a finite amount of work, to move them until they're a small distance \(d\) apart?

How does the energy density at a certain distance from a negative point charge compare with the energy density at the same distance from a positive point charge of equal magnitude?

A dipole consists of two equal but opposite charges. Is the total energy stored in the dipole's electric field zero? Why or why not?

Charge is spread over the surface of a balloon, which is then allowed to expand. What happens to the energy of the electric field?

Does the superposition principle hold for electric-field energy densities? That is, if you double the field strength at some point. do you double the energy density as well?

A student argues that the total energy associated with the electric field of a charged sphere must be infinite because its field extends throughout an infinite volume. Critique this argument.

A capacitor is said to carry a charge \(Q .\) What's the net charge on the entire capacitor?

Does the capacitance describe the maximum amount of charge a capacitor can hold, in the same way that a bucket's capacity describes the maximum amount of water it can hold? Explain.

Is a force needed to hold the plates of a charged capacitor in place? Explain.

A solid conducting slab is inserted between the plates of a capacitor, not touching either plate. Does the capacitance increase, decrease, or remain the same?