Question

What is the effective capacitance between points X and Y?

• A. $24\mu F$
• B. $18\mu F$
• C. $12\mu F$
• D. $6\mu F$

Answer 1

Answer: (D)

$6\mu F$

It is a Wheatstone bridge circuit and here $\frac{C_1}{C_3}=\frac{C_2}{C_4}$. Thus no charge will flow through $C_5=20\mu F$.
As $C_1$ and $C_3$ are in series so $C_{13}=\frac{6\times 6}{6+6}=3\mu F$
and also $C_2$ and $C_4$ are in series so $C_{24}=\frac{6\times 6}{6+6}=3\mu F$
now $C_{13}$ and $C_{24}$ are in parallel so $C_{XY}=C_{13}+C_{24}=3+3=6\mu F$