Practice question

**Superposition principle** asserts net Coulomb force on charge equals vector sum of forces from each other charge independently, F_net = Σ F_i, where F_i = k q q_i/r_i² r̂_i. In equilateral triangle or square symmetry, components may cancel at centroid, producing equilibrium. The inverse-square law governs the field from charges on the surface. Near the surface, the distance r is small, making 1/r² large, resulting in a strong field that weakens rapidly as distance increases. Substituting values gives Inverse-square law, which matches expected magnitude for this electrostatic configuration, confirming Coulomb's and Gauss's principles and charge quantization consistency.