a parallel-plate capacitor has capacitance c = 12.5 pf when the volume between the plates is filled with air. the plates are circular, with radius 3.00 cm. the capacitor is connected to a battery and a charge of magnitude 25.0 pc goes onto each plate. with the capacitor still connected to the battery, a slab of dielectric is inserted between the plates, completely filling the space between the plates. after the dielectric has been inserted the charge on each plate has magnitude 45.0 pc.