A parallel-plate capacitor in air has a plate separation of 1.50 cm and a plate area of 25.0 cm2. The plates are charged to a potential difference of 250 V and disconnected from the source. The capacitor is then immersed in distilled water. Determine
(a) The charge on the plates before and after immersion,
(b) The capacitance and potential difference after immersion, and
(c) The change in energy of the capacitor. Assume the liquid is an insulator.