Question

In the circuit shown, the potential difference across the condenser of capacity 6C is 10 V. The voltage of the battery is

• A. 70 V
• B. 35 V
• C. 30 V
• D. 45 V

Answer 1

The correct option is A 70 V

$C=\frac{10}{6}F$

$\frac{3\times 6}{3+6}+2=\frac{18}{9}+2=4$

equivalent $=\frac{4\times 3}{4+3}=\frac{4\times 3}{7}=\frac{12}{7}C$

$V=\frac{Q}{C}$

$V_1=V\times \frac{6}{12}\times 7$

Now,

$V_1=V\times \frac{\frac{12}{7}}{12}$

or, $10=V\times \frac{12}{7}\times \frac{1}{12}$

or, $V=70V$