A gold-leaf electroscope has a vertical rod R attached to a flat metal plate. Electroscopes detect electric charge by the motion of a test object due to the Coulomb electrostatic force. Since the elec...A gold-leaf electroscope has a vertical rod R attached to a flat metal plate. Electroscopes detect electric charge by the motion of a test object due to the Coulomb electrostatic force. Since the electric potential or voltage of an object with respect to ground equals its charge divided by its capacitance to ground, an electroscope can be regarded as a crude voltmeter.
