TOPIC:

ID Code: J4-03
Purpose: Demonstrate the effect of capacitors in series.
Description: The parallel plate capacitor is charged using a low-current DC power supply and separated as shown. A thin metal sheet is then inserted between the two capacitor plates, forming two capacitors in series. The voltage read by the electrometer remains virtually the same, indicating that the capacitance of the series capacitors is the same:

C = C1 C2 / (C1 + C2),

where either capacitance C is inversely proportional to the distance between the plates.
Availability: Available

See the Physics Question of the Week for 2/17/2014 for an example of how this demonstration can be used in class interaction and discussion: lecdem.physics.umd.edu/question-of-the-week-archive.html