29. A capacitor is charged to store an energy U. The charging battery is disconnected. An identical capacitor is now connected to the first capacitor in parallel. The energy in each of the capacitor is ?

A capacitor is charged to store an energy U. The charging battery is disconnected. An identical capacitor is now connected to the first capacitor in parallel. The energy in each of the capacitor is ?

(a) U/2

(b) 3U/2

(c) U

(d) U/4

Answer :  (d) U/4

\( U = \frac{1}{2} C V^2 \)

\( U_{\text{new}} = \frac{1}{2} C \left( \frac{V}{2} \right)^2 \)

\( = \frac{U}{4} \)