Q114 / 180 · NEET 2017 · Physics

A capacitor is charged by a battery. The battery is removed and another identical uncharged capacitor is connected in parallel. The total electrostatic energy of resulting system

  • A
    increases by a factor of 4.
  • Correct answer
    B
    decreases by a factor of 2.
  • C
    remains the same.
  • D
    increases by a factor of 2.

Solution

Figure
Charge on capacitor,
q=CV

When it is connected with another uncharged capacitor.
Figure
Vc=q1+q2C1+C2=q+0C+C
Vc=V2
Initial energy,
Ui=12CV2
Final energy,
Uf=12CV22+12CV22

=CV24

Loss of energy =Ui-Uf
=CV24,
i.e., decreases by a factor of 2.

Hence, the correct answer is option: 'B'.

More Capacitance Questions