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Physics · PYQ NEET UG 2022
हिन्दीA capacitor of capacitance \( C = 900\text{ pF} \) is charged fully by \( 100\text{ V} \) battery B as shown in figure (a). Then it is disconnected from the battery and connected to another uncharged capacitor of capacitance \( C = 900\text{ pF} \) as shown in figure (b). The electrostatic energy stored by the system (b) is:
Correct answer · Option 1
\( 2.25 \times 10^{-6}\text{ J} \)
Explanation
Initial energy \( U_i = \frac{1}{2} C V^2 \). When connected in parallel to an identical uncharged capacitor, the final potential becomes \( V/2 \), and the total energy stored becomes \( U_f = 2 \times [ \frac{1}{2} C (\frac{V}{2})^2 ] = \frac{1}{4} C V^2 = 2.25 \times 10^{-6}\text{ J} \).
