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JEE Main 20205 SeptemberMorning Shift
Exam
JEE Main
Year
2020
Date
5 September
Shift
Morning Shift
Subject
Physics
Chapter
Capacitance

JEE Main 2020 · 5 September · Morning Shift · Physics · Capacitance

Two capacitors of capacitances C and 2C are charged to potential...

Two capacitors of capacitances CC and 2C2C are charged to potential differences VV and 2V2V, 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 :Two capacitors of capacitances C and 2C are charged to potential differences V and 2V , respectively. These are thenTwo capacitors of capacitances C and 2C are charged to potential differences V and 2V , respectively. These are then

Options

  1. A256CV2\dfrac{25}{6}C{V}^{2}
  2. B32CV2\dfrac{3}{2}C{V}^{2}
  3. Czero
  4. D92CV2\dfrac{9}{2}C{V}^{2}

Correct answer

B. 32CV2\dfrac{3}{2}C{V}^{2}

Step-by-step solution

Two capacitors of capacitances C and 2C are charged to potential differences V and 2V , respectively. These are then

Charge on C=CVC = CV
Charge on 2C=(2C)2V2C = \left(2C\right)2V

Two capacitors of capacitances C and 2C are charged to potential differences V and 2V , respectively. These are then

From charge conservation, 2C(2V)−CV=(C+2C)V′2C ( 2V ) - CV = ( C + 2C ) V '
Common potential, V′=VV ' = V
Final energy, Uf=(12CV2+12×2CV2)=32CV2{U}_{f} = \left(\dfrac{1}{2}C{V}^{2} + \dfrac{1}{2} \times 2C{V}^{2}\right) = \dfrac{3}{2}C{V}^{2}

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