Define the principle of conservation of electric charge. Explain it with an example.

The total electric charge in an isolated system is conserved. Electric charge can neither be created nor destroyed.
If a metal conductor kept on an isolated stand has a charge of 12 units, and it is brought into contact with an identical uncharged insulated metal conductor and then removed, the charge on each metal conductor will be 6 units, so that the total charge is 6 + 6 = 12 units, which remains constant or conserved.