1 6. The voltage between the plates of a 4 nF parallelplate air capacitor is 6 V, and the plates are separated by a distance of 2 mm. A dielectric, with dielectric constant equal to 3, is then inserted between the plates after the battery that charged the capacitor is disconnected. Determine the final stored electrical potential energy in this capacitor. A 96 DJ B 216 nJ C 72 DJ D 24 ml E 48 DJ