Solve the all parts of given question:
Question: A parallel plate capacitor is made from circular plates of Aluminum foil each with a radius of 3 cm. The distance between the plates is 8 mm. A 120 V emf is connected to the plates.
Part A: Find the charge stored in this capacitor.
Part B: Calculate the amount of energy stored in the capacitor.
Part C: If one were to keep the 120 V battery connected while increasing the separation between the plates to 12 mm, what would be the final energy stored in the capacitor?
Part D: If instead one disconnects the battery and increases the distance between the plates to 12 mm, what would be the final energy stored in the capacitor?
Please explain how you solved the all parts of above question, thanks!