Question

All the capacitance in the figure are of capacitance $C$. The effective capacitance between $P$ and $Q$ is :

• A. $2C$
• B. $3C$
• C. $4C$
• D. $1.5C$

Answer 1

Answer: (D)

$1.5C$

Here first 3 capacitors are in parallel and then the 3 capacitors are also in parallel and thereafter the equivalent capacitances of both are in series as shown in figure below.
$C_{eq}^1=C+C+C=3C$ and also $C_{eq}^2=C+C+C=3C$
$C_{eq}=\frac{C_{eq}^1{C}_{eq}^2}{C_{eq}^1+C_{eq}^2}=\frac{9C^2}{6C}=\frac{3}{2}C=1.5C$