Practice question

**Inverse-square law** for charges states F ∝ 1/r² while increasing with charge product. Using k = 9×10⁹ N·m²/C², force at distance r follows F = k q₁q₂/r², forming basis for pairwise force calculation. Electric field lines represent the direction of the field at each point. If they intersected, it would imply two different field directions at the same point, which is impossible since the electric field is a unique vector quantity at any given position. Substituting values gives Uniqueness of direction, which matches expected magnitude for this electrostatic configuration, confirming Coulomb's and Gauss's principles and charge quantization consistency.