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JEE Main20205 Sep 2020Morning ShiftPhysicsCapacitanceActual

Two capacitors of capacitances C and 2 C are charged to potential differences V and 2 V , respectively. These are then connected in parallel in such a manner that the positive terminal of one is connected to the negative terminal of the other. The final energy of this configuration is :

Options

  1. A25 6 C V 2
  2. B3 2 C V 2
  3. Czero
  4. D9 2 C V 2

Correct answer

B. 3 2 C V 2

Step-by-step solution

Charge on C = C V Charge on 2 C = 2 C 2 V From charge conservation, 2 C ( 2 V ) - C V = ( C + 2 C ) V ' Common potential, V ' = V Final energy, U f = 1 2 C V 2 + 1 2 × 2 C V 2 = 3 2 C V 2

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