Question

A $10\mu F$ capacitor is charged to a potential difference of $50V$ and is connected to another uncharged capacitor in parallel. Now the common potential difference becomes 20 volts. The capacitance of the second capacitor is

• A. $10\mu F$
• B. $20\mu F$
• C. $30\mu F$
• D. $15\mu F$

Answer 1

The correct option is D $15\mu F$

$Q=10\times 50=500\mu C$

Second case:

$500=(C+10)\times 20$

$\Rightarrow C=15\mu F$