A1 uf parallel-plate capacitor is charged to 12 v and then disconnected from the voltage supply. the plate separation distance is doubled and the dielectric is replaced by a material with another that has one quarter of the former relative permittivity. find the final charge on the capacitor's positive plate and the final voltage difference between its terminals. 2. a parallel-plate capacitor consists of two equally thick layers of dielectric sandwiched between 1 cm x 2 cm rectangular plates that are separated by 200 um. one layer of dielectric has permittivity of 5 uf/m. the other has twice that value. find the energy stored in the capacitor when its leads are connected to a 60 v supply.