Question

In the figure shown, the potential difference between points A and B is :

• A. $10\text{V}$
• B. $30\text{V}$
• C. $7.5\text{V}$
• D. None

Answer 1

The correct option is A $10\text{V}$


The above circuit is simplified by replacing $C_2,C_3,C_4$ series capacitance by it equivalent

$\frac{1}{C_{\text{eq}}}=\frac{1}{C_2}+\frac{1}{C_3}+\frac{1}{C_4}$

$C_2=C_3=C_4=6\mu \text{F}$
$\therefore C_{\text{eq}}=2\mu \text{F}$

Equivalent circuit,



Potential difference across $2\mu \text{F}$ capacitor is $30\text{V}$
So charge on it is $60\mu \text{C}$
As charge is equal on each capacitor in series,
Charge on $C_3$ is $60\mu \text{C}$
Potential difference across $C_3$ is $\frac{60}{6}=10\text{V}$