Consider an air filled parallel plate capacitor with plate area A and gap width d. The plate charge is Q. The total energy stored in the capacitor is given by U= Q^2 *d /2 E_o A. With the battery connected, fill the gap by a slab with the dielectric constant k. Given : E= 70 V, k= 3.8, d=0.8 mm and A = 25.6 cm^2, E_o = 8.85 x 10^-12 C^2/Nm^2, find the electric charge on the plate. Answer in units of C. I really have no idea how to do this. I know that I have everything needed to find the total energy, but I don't really know how to get the charge from that. Can someone help?