A parallel-plate capacitor with plates of area 600 cm2 is charged to a potential difference V and is then disconnected from the voltage source. When the plates are moved 0.3 cm farther apart, the voltage between the plates increases by 100 V.
(a) What is the charge Q on the positive plate of the capacitor?
(b) How much does the energy stored in the capacitor increase due to the movement of the plates?