Question

Three capacitors are connected across a 45V power supply as shown in figure. What is the charge on the 6$\mu$F capacitor?

• A. 60$\mu$C
• B. 90$\mu$C
• C. 120$\mu$C
• D. 180$\mu$C

Answer 1

Answer: (B)

90$\mu$C

As capacitors $6$ and $2$ are in parallel so equivalent capacitance $C_{eq}=6+2=8\mu F$
Now capacitors $4$ and $8$ are in series. Potential across capacitor $8$ is $V_8=\frac{4}{(4+8)}\left(45\right)=15V$
As capacitors 6 and 2 are in parallel so potential across each capacitor is equal to $15V$.
Thus charge on capacitor $6$ is $Q_6=6\left(15\right)=90\mu C$