Three capacitors connected in series have capacitance of 9pF each. (1) What is the total capacitance of the combination? (2) What is the potential difference across each capacitor if the combination is connected to a 120 V supply?
(A) Effective capacitance in series combination is given by: Cs1=C11+C21+C31 Cs1=91+91+91 ⇒Cs=03pF so, total capacitance of the combination is 3pF (B) Q=CsV Q=3×120=360pC V1=C1Q (as in series combination, charges is constant) ⇒9360=40V V2=C2Q=9360=40V V3=C3Q=9360=40V
