Question

In the arrangement shown in figure, when switch $S$ is closed, find the final potential difference across the $4\mu F$ capacitor :

• A. $12V$
• B. $8V$
• C. $20V$
• D. $32V$

Answer 1

The correct option is B $8V$

In the close loop:

$\frac{q_0-\Delta q}{C_1}-\frac{\Delta q}{C_2}-\frac{\Delta q}{C_2}=0$

$\frac{q_0}{C_1}=\Delta q[\frac{1}{C_1}+\frac{1}{C_2}+\frac{1}{C_3}]$

$\Delta q=\frac{q_0}{C_1[\frac{1}{C_1}+\frac{1}{C_2}+\frac{1}{C_3}]}=\frac{192}{[1+3+2]}=32\mu C$