Question:
In the circuit shown in the figure, the total charge is $750 \mu \mathrm{C}$ and the voltage across capacitor $C_{2}$ is $20 \mathrm{~V}$. Then the charge on capacitor $C_{2}$ is :
Correct Option: 2,
Solution:
(2) According to question,
$Q=750 \mu C=q_{2}+q_{3}$
Capacitors $C_{2}$ and $C_{3}$ are in parallel hence, Voltage across $C_{2}=$ voltage across $C_{3}=20 \mathrm{~V}$ Change on capacitor $C_{3}$,
$q_{3}=C_{3} \times V_{3}=8 \times 20=160 \mu C$
$\therefore q_{2}=750 \mu C-160 \mu C=590 \mu C$