Practice question

**Electric flux** through surface measures field lines crossing it, Φ = E·A = E A cosθ for uniform field, unit N·m²/C. For circular area in xy-plane with field along z, θ = 0°, cosθ = 1, so Φ = E·πR² directly, maximum when field normal to surface. Total flux: Φ = (q/ε₀) = (3 × 10⁻⁶/8.854 × 10⁻¹²) = 3.39 × 10⁵ N·m²/C . Flux per face (6 faces): Φfₐcₑ = (3.39 × 10⁵/6) = 5.65 × 10⁴ N·m²/C . Substituting values gives 5.65 × 10⁴ N·m²/C, which matches expected magnitude for this electrostatic configuration, confirming Coulomb's and Gauss's principles and charge quantization consistency.