Q: A parallel plate capacitor has plates of area A and separation d and is charged to a potential difference V. The charging battery is then disconnected and the plates are pulled apart until their separation is 2d. What is the work required to separate the plates?
(a) 2ε0AV²/d
(b) ε0AV²/d
(c) 3ε0AV²/2d
(d) ε0AV²/2d
Ans: (d)