Question

Three capacitors are connected in the shape of a triangle ABC as shown below. A voltage of 4V is applied between B and C. Calculate the voltage between A and C.

• A. 4V
• B. 3V
• C. 5V
• D. 2V

Answer 1

Answer: (D)

2V

Answer 2

When 4V is applied between B and C, the capacitors $C_{AB}$ ($2\mu F$) and $C_{AC}$ ($2\mu F$) are in series across this 4V. The equivalent capacitance of this series combination is $1\mu F$. The total charge flowing through this series path is $Q = C_{eq} \times V = 1\mu F \times 4V = 4\mu C$. Since capacitors in series have the same charge, the charge on $C_{AC}$ is $4\mu C$. The voltage across $C_{AC}$ is $V_{AC} = Q_{AC} / C_{AC} = 4\mu C / 2\mu F = 2V$.