Question

Q1. You use a battery to charge the plates of an ideal parallel plate capacitor. When you disconnect the battery, do the plates of the capacitor remain charged or do they discharge? Explain why they do or do not stay charged.  

Answer 1

Given

ideal battery of capacitance C , the charge can store is Q , the voltage or potential difference by the battery is v

then from the relation

Q = C*V

as long as the battery connected the charges were deposited on the plates causing the electric field of the charges results the potential difference is equal to the battery potential

if we disconnect the battery then the charge is same on the capacitor

Q = C*V

if no material present between the plates and the no other elements in the cicuit the charge will remain change.