You’re trying to convince a friend that nuclear energy represents a much more concentrated energy source than fossil fuels, whose combustion involves rearranging atomic electrons. For a rough comparison, you calculate the ground-state energy of a proton confined to 1-fm-diameter atomic nucleus and that of an electron confined to a 0.1-nm-diameter atom. Approximating each system as a one-dimensional infinite square well, what’s the ratio of their ground-state energies?