Final answer:
In electrostatic equilibrium, charges distribute themselves on a conductor in such a way that the electric field inside is zero. The distribution of charges on the surface is unique. The uniqueness can be argued using the uniqueness theorem, which states that there is only one potential function that satisfies the given boundary conditions and Poisson's equation outside the conductor.
Step-by-step explanation:
When a conductor is in electrostatic equilibrium, the charge distributes itself in such a way that the electric field inside the conductor is zero. This is because any electric field inside the conductor would cause the charges to move, resulting in a nonstatic condition, which contradicts the assumption of electrostatic equilibrium. The distribution of charges on the surface of the conductor is unique, meaning that only one kind of charge distribution is possible under these conditions.
This uniqueness can be argued using the uniqueness theorem, which states that there is only one potential function that satisfies the given boundary conditions and Poisson's equation outside the conductor. Since a particular potential function corresponds to a particular charge distribution, the charge distribution must also be unique.