Does an electroscope losing its charge by being grounded violate the law of conservation of charge?
http://en.wikipedia.org/wiki/Charge_conservation
No, when an electroscope loses its charge by being grounded, it does not violate the law of conservation of charge. The law of conservation of charge states that the total amount of electric charge in a closed system remains constant over time.
When an electroscope gets charged, the charge is distributed throughout the metal body and its leaves. This causes them to repel each other and stand apart. However, when the electroscope is grounded, it means that it is connected to the Earth or any other large conductor, which acts as a pathway for charge to flow.
When the electroscope is grounded, the excess charges that have accumulated on the metal body and leaves can flow through this pathway and get neutralized by the opposite charges in the Earth. This process is known as grounding or discharging. It restores the neutral state of the electroscope, making the leaves collapse back together.
So, while the electroscope loses its charge during grounding, the total amount of charge in the system remains the same. The excess charge is simply redistributed and neutralized, obeying the law of conservation of charge.