An uncharged solid spherical conductor contains a cavity within it. A point charge +Q is placed inside the cavity without touching its walls. What will be the induced charges on the inner surface of the cavity and the outer surface of the conductor, respectively?

Step-by-step solution

Consider a Gaussian surface entirely within the solid material of the conductor, enclosing the cavity. In electrostatic equilibrium, the electric field inside the conducting material is zero everywhere. According to Gauss's law, the net flux through this surface is zero, which means the net charge enclosed must be zero. Therefore, an induced charge of -Q must appear on the inner surface of the cavity to exactly cancel the +Q point charge inside. Since the conductor is initially uncharged and isolated, its total cha