Capacitor A consists of two circular conducting plates of radius 3.0 cm separated by…
PHYSICS · Multi-part · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
Capacitor A consists of two circular conducting plates of radius 3.0 cm separated by 1.5 mm with air between them. Capacitor B uses plates of the same radius, but the separation is 0.50 mm and the space is filled with a dielectric fluid of unknown constant κ. Both capacitors are isolated from one another and are charged to the same potential difference before any measurements are taken.
(a) Derive an expression for the ratio CB/CA in terms of the given geometric quantities and the unknown dielectric constant.
(b) A laboratory measurement finds that CB/CA=4.2. Determine the dielectric constant κ of the fluid.
(c) Identify one experimental uncertainty that could affect the accuracy of the ratio measurement and discuss a method to minimize its impact.