Question

Two capacitors of $3$ $\mu F$ and $6$ $\mu F$ are connected in series and a potential difference of $900$V is applied across the combination. They are then disconnected and reconnected in parallel. The potential difference across the combination is?

• A. Zero
• B. $100$ V
• C. $200$ V
• D. $400$ V

Answer 1

Answer: (C)

$200$ V

Initial charge $q=\left(\frac{3\times 6}{3+6}\right)900=1800\mu C$
Common potential $V=\frac{Totalcharge}{Totalcapacity}$

$=\frac{1800}{9}=200V$.