Question

Find the equivalent capacitance across A and B for the arrangement shown in figure. All the capacitors are of capacitance C :

• A. $\frac{3C}{14}$
• B. $\frac{C}{8}$
• C. $\frac{3C}{16}$
• D. none of these

Answer 1

The correct option is A $\frac{3C}{14}$

Here three capacitors will not working because they are short in the circuit and the corresponding circuit is shown in figure.
The equivalent capacitance on right parallel branch is $C_{eq}=\frac{CC}{C+C}+C=\left(3/2\right)C$.
Now all the capacitors are in series so equivalent capacitance across A and B is
$C_{AB}=(1/C+1/C+1/C+2/3C+1/C{)}^{-1}=(4/C+2/3C{)}^{-1}=(14/3C{)}^{-1}=3C/14$