Question

For the circuit shown in the figure, the charge flown through the switch after it is closed is $n\mu C$ . Find the value of $n$ .

Answer 1

Answer: 30

Initial charge on upper middle part of the circuit connected to switch,
$Q_i=0$
When switch is connected, both pair of $1\mu F$ and $4\mu F$ will be in parallel & both pairs will be at potential difference of $10V$ , hence charge on left side of the upper middle part(negative plate) $=1\mu F\times 10V=10\mu C$
and charge on right side of the upper middle part(positive plate) $=4\mu F\times 10V=40\mu C$
Hence, net charge on upper middle part now is $Q_f=-10+40=30\mu C$