Practice question

**Electric field concept** visualizes influence of source charge. Uniform field exerts constant force F = qE, and flux Φ = E·A = E A cosθ links field to area orientation, maximum when field normal to surface. E₁ = (k |q₁|/r²) = 9 × 10⁹ × (4 × 10⁻⁶/(0.2)²) = 9 × 10⁵ N/C (away). E₂ = 9 × 10⁹ × (8 × 10⁻⁶/(0.2)²) = 1.8 × 10⁶ N/C (towards). Angle between E₁ and E₂ is 60°. Net E = √(E₁² + E₂² + 2 E₁ E₂ cos 60°) . E = √((9 × 10⁵)² + (1.8 × 10⁶)² + 2 × 9 × 10⁵ ×