Practice question

**Dipole moment** governs torque and energy in external field. Axial field stronger than equatorial, torque maximum at θ = 90°, zero when aligned. Work done rotating dipole relates to ΔU = pE(1 - cosθ), explaining stable equilibrium at θ = 0°. tau = p E sin θ . tau = 6 × 10⁻⁹ × 3 × 10⁴ × sin 60° = 18 × 10⁻⁵ × (√(3)/2) = 1.56 × 10⁻⁴ N m . Substituting values gives 1.56 × 10⁻⁴ N m, which matches expected magnitude for this electrostatic configuration, confirming Coulomb's and Gauss's principles and charge quantization consistency.