Equal but opposite charges Q are placed on the square plates of an air-filled parallel-plate capacitor.The plates are then pulled apart to twice their original separation,which is small compared to the dimensions of the plates.Which of the following statements about this capacitor are true? (There may be more than one correct choice.)
A) The energy stored in the capacitor has doubled.
B) The energy density in the capacitor has increased.
C) The electric field between the plates has increased.
D) The potential difference across the plates has doubled.
E) The capacitance has doubled.

Question

Quizplus · Accepted Answer

When the separation between the plates is doubled, the capacitance is halved, but the charge remains constant, leading to a doubling of the potential difference (V = Q/C). The energy stored (U = 1/2 QV) also doubles as a result.

Equal but Opposite Charges Q Are Placed on the Square