Equal but opposite charges Q are placed on the square plates of an airfilled 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 capactiance has doubled.

Please explain why you chose that answer.

A) The energy stored in the capacitor has doubled.

D) The potential difference across the plates has doubled.

E) The capacitance has doubled.

Explanation:

According to the formulas, E = QV^2 and Capacitance = (epsilon) A/d

The potential difference between the plated has been doubled as the separations have been increased by two times. As the potential difference has been doubled, the energy stored in the capacitor has also been doubled. The overall capacitance will be increased by two times as the separation increases.

the motion of a pendulum is a classic example of mechanical energy conservation. a pendulum consists of a mass (known as a bob ) attached by a string to a pivot point. as the pendulum moves it sweeps out a circular arc, moving back and forth in a periodic fashion.