A uniform electric field, with a magnitude of 500 V/m, is directed parallel to the +x axis. If the potential at x = 5.0 m is 2500 V, what is the potential at x = 2.0 m?

Three reasons for adding a dielectric material between the plates of a capacitor.
1. Dielectrics do not break down (allowing electric charge to flow"as readily as air, so a higher voltage can be applied without charge passing across the gap.
2. A dielectric allows the plates to be placed closer together without touching thus allowing an increased capacitance because the plate separation is less.
3. If a dielectric fills the space between the two conductors, it increases the capacitance.