The parallel plates in a capacitor, having a plate area of 9.40 cm2 and an air-filled separation of 4.00 mm, are charged through a 8.20 V battery. They are then detached from the battery and pulled apart (without discharge) to a separation of 7.00 mm. Avoiding fringing, find out (a) the potential difference (in V) between the plates, (ii) the initial stored energy, (iii) the final stored energy, and (iv) the work needed to separate the plates.