Three capacitors each of capacitance 9 pF are connected in series.

(a) What is the total capacitance of the combination?

(b) What is the potential difference across each capacitor if the combination is connected to a 120 V supply?

Given, C₁ = C₂ = C₃ = 9 pF = 9 x 10^-12 F

V = 120 volt

(a) Total capacitance of the series combination is given by

⇒

⇒

C_net = 3 x 10^-12 F = 3 pico-Farad.

(b) Let q be the charge on each capacitor.

Sum of the potential difference across the plates of the three capacitors must be equal to 120 V

⇒ V₁ + V₂ + V₃ = V_net

⇒ (∵ V_net = 120 V)

⇒

⇒

⇒ q = 360 x 10^-12 C

Therefore, potential difference across a capacitor