Question

Capacitors of 2μF and 6μF are connected to a 100V battery. How much charge I supplied by the battery in charging the capacitors when (a) they are connected in series and (b) when they are connected in parallel?

Answer 1

(a)

$$C_{eq}=\frac{C_1C_2}{C_1+C_2}=\frac{2*6}{2+6}=1.5\:\rm \mu F$$

$$q_1=q_2=C_{eq}V\\ =1.5*10^{-6}*100=1.4*10^{-4}\:\rm C$$

(b)

$$q_1=C_{1}V\\ =2*10^{-6}*100=2*10^{-4}\:\rm C$$

$$q_2=C_{2}V\\ =6*10^{-6}*100=6*10^{-4}\:\rm C$$