Question

The plates of an air-filled parallel-plate capacitor with a plate area of 18.5 cm2 and a separation of 9.25 mm are charged to a 125-V potential difference. After the plates are disconnected from the source, a porcelain dielectric with κ = 6.5 is inserted between the plates of the capacitor.
(a) What is the charge on the capacitor before and after the dielectric is inserted?
Qi=C Qf=C

(b) What is the capacitance of the capacitor after the dielectric is inserted?
F

(c) What is the potential difference between the plates of the capacitor after the dielectric is inserted?
V

(d) What is the magnitude of the change in the energy stored in the capacitor after the dielectric is inserted?J
J