Parallel plate capacitor with dielectric materials and electroscope.

Parallel plate capacitor with dielectric materials and electroscope. The electroscope is charged with a relatively small charge (using an Electrophorous or 5000 V.D.C. power supply). As the plates are drawn further apart, the deflection of the electroscope needle increases. Sheets of various dielectric materials can be inserted between the plates. E.G.: Plexiglass has a higher dielectric constant than air. Inserting the plexiglass causes a reduced deflection of the electroscope needle. For the plate capacitor, Q = CV ; V = Q/C. Thus the potential across a capacitor with constant charge is inversely proportional to the capacitance . Capacitance is proportional to the dielectric constant, and inversely proportional to the distance between the plates. Thus V (and the deflection of the electroscope needle) is proportional to the distance between the plates, and inversely proportional to the dielectric constant of the inserted material. Spacing of plates may be varied CAPACITANCE.