First slide

Redistribution of charges and concept of common potential

Question

A $5 μ F$ capacitor is charged fully by a 220V supply. It is then disconnected from the supply and is connected in series to another uncharged $2.5 μ F$ capacitor. If the energy change during the charge redistribution is $\frac{X}{100} J$ then value of X to the nearest integer is_______.

Moderate

Solution

Energy lost during charge redistribution
$\begin{array}{l} = \frac{1}{2} \frac{C_{1} C_{2}}{C_{1} + C_{2}} {(V_{1} - V_{2})}^{2} \\ = \frac{1}{2} \frac{5 \times 2.5}{5 + 2.5} \times {(220 - 0)}^{2} \times 10^{- 6} \\ (∵ F o r u n c h a r g e d c a p a c i \tan c e V = 0) \\ = \frac{5}{6} \times {(2.2)}^{2} \times 10^{- 2} = \frac{X}{100} \\ \Rightarrow x = \frac{5 \times {(2.2)}^{2}}{6} = 4.03 \end{array}$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App