Worksheet Capacitors - Connected/Disconnected Batteries
Refer to the following information for the next seven questions.

A 100 µF parallel-plate capacitor is charged  to 500 V. It is then disconnected from the charging source and insulated.
 (a) How much charge is present on the plates of the capacitor?

 (b) How much energy is stored on the capacitor

 The plates are now pulled apart to a separation that is twice their original distance.   (c) What charge is now stored on the plates of the capacitor?

 (d) What is the new capacitance of the capacitor?

 (e) What voltage is now across the plates of the capacitor?

 (f) What energy is now stored on the capacitor?

 (g) If this does not agree with your answer to part (b) account for the difference?

Refer to the following information for the next seven questions.

A 100 µF parallel-plate capacitor is charged to 500 V and continues to remain connected to the charging source.
 (a)  How much charge is present on the plates of the capacitor?

 (b)  How much energy is stored on the capacitor?

 The plates are now pulled apart to a separation that is twice their original distance.   (c) What voltage is across the plates of the capacitor?

 (d) What is the new capacitance of this capacitor?

 (e) What charge is stored on the plates of the capacitor?

 (f) What energy is stored on the capacitor?

 (g)  If this does not agree with your answer to part (b) account for the difference?

Refer to the following information for the next eight questions.

A parallel-plate capacitor made of circular plates of radius 25 cm separated by 0.20 cm is charged to a potential difference of 1000V by a battery.
 (a) What is the capacitance of this capacitor?

 (b) How much charge is stored on the original capacitor?

 (c) How much energy is stored in the capacitor?

 While remaining connected to the battery, a sheet of polyethylene (K = 2.3) is inserted between the plates, completely filling the gap between them.   (d) What is the voltage across the capacitor once the polyethylene is inserted?

 (e) What is the capacitance of the capacitor once the polyethylene is inserted?

 (f) How much charge is stored on the capacitor once the polyethylene is inserted?

 (g) How much additional charge flowed from the battery to each plate when the polyethylene was inserted?

 (h) How much energy is now stored on the capacitor?