Question

If a capacitor $900\mu F$ is charged to $100V$ and its total energy is transferred to a capacitor of capacitance $100\mu F$ then its potential is :

• A. $200V$
• B. $30V$
• C. $300V$
• D. $400V$

Answer 1

Answer: (C)

$300V$

Let the final potential is $V_2$.
As the total energy of first capacitor is transferred to second capacitor so $U_1=U_2$
Thus, $\frac{1}{2}{C}_1{V}_1^2=\frac{1}{2}{C}_2{V}_2^2$

$900\times {10}^{-6}\times (100{)}^2=100\times {10}^{-6}\times V_2^2$

$V_2^2=900\times 100\Rightarrow V_2=300V$