Q. Seven capacitors, each of capacitance $2 \mu F$, are to be connected in a configuration to obtain an effective capacitance of $\left(\frac{6}{13}\right)\mu F$. Which of the combinations, shown in figures below, will achieve the desired value ?
Solution:
$C_{eq} = \frac{6}{13} \mu F$
Therefore three capacitors most be in parallel to get $6$ in
$ \frac{1}{C_{eq}} = \frac{1}{3C} + \frac{1}{C} + \frac{1}{C}+\frac{1}{C} + \frac{1}{C} $
$ C_{eq} = \frac{3C}{13} = \frac{6}{13} \mu F $
