In: Physics
A disk-shaped parallel plate capacitor is made with a radius of 2 cm and a plate separation distance of 2/π millimeters. The dielectric is in two layers, each of thickness 1/π mm. The first layer is all composed of a material with dielectric constant 9. The second layer is actually made of two materials in a bullseye pattern. The inner circle has radius 1 cm and dielectric constant 6. The annular ring around it has dielectric constant 4. The entire capacitor is charged up on a 360 V and then disconnected from the voltage source. While it is still charged, the plates are moved farther apart to accommodate another layer 1/π mm thick of material with dielectric constant 1. Find the final voltage and charge on the capacitor. Use 9x10^-12 C²/J·m for the permittivity of empty space.