A parallel-plate capacitor with plate area 2.0 cm2 and air-gap separation 0.20 mm is connected to a 12 V battery, and fully charged. The battery is then disconnected.
(a) What is the charge on the capacitor?
(b) The plates are now pulled to a separation of 0.80 mm. What is the charge on the capacitor now?
(c) What is the potential difference across the plates now?
(d) How much work was required to pull the plates to their new separation?