Question

Both capacitors are initially uncharged and then connected as shown and switch is closed. What is the charge across the $3\mu F$ capacitor?

• A. $40\mu C$
• B. $30\mu C$
• C. $50\mu C$
• D. $15\mu C$
  

Answer 1

The correct option is B $30\mu C$

Applying $KVL$
Let charge q flow through the circuit.

Apply Kirchhoff’s voltage law,
( taking potential rise +ve, moving anticlockwise)

$19V-\frac{q}{\left(2\mu F\right)}-9V-\frac{q}{\left(3\mu F\right)}+15V=0$
(in capacitor , $V=q/c$)

$25V-\frac{5q}{6}=0$

$q=30\mu C$

Hence, correct option is $\left(A\right)$