Practice question

**Charge conservation in series** explains same Q: when battery charges first plate, it induces -Q on second plate of same capacitor, which comes from next capacitor's plate, etc., so all have same magnitude Q, potential divides as per 1/C. Work done: W = p E (cos θ₀ - cos θ₁) = 2 × 10⁻⁹ × 5 × 10⁵ × (cos 90° - cos 0°) = 2 × 10⁻⁹ × 5 × 10⁵ × (0 - 1) = -10⁻³ J . Using V = kQ/r, U = k q₁q₂/r, E = -dV/dr, C = ε₀A/d, 1/C_eq series, C_eq = ΣC parallel, U = ½ C V²