If you suspend a metal ball by an insulating thread between two vertical plates the ball shuttles back and forth when a high voltage is applied across the two plates.If the ball shuttles back and forth at a frequency f moving a charge of Q cross the gap each cycle, the average current I = QfExample
If the reading on the microammeter is 40nA and the frequency of the ball is 8.0Hz, the charge carried by the ball is I/f = 40×10-9/8.0 which is 5.0×10-9C.
If the reading on the microammeter is 40nA and the frequency of the ball is 8.0Hz, the charge carried by the ball is I/f = 40×10-9/8.0 which is 5.0×10-9C.