Question

when the glass rod comes in contact with the metal disc of the electroscope, the gold leaves _​

Answer 1

hii here there is your answer

The following quote from Daniell explains how this works: "In the discharging electroscope the gold leaves when they diverge, come in contact with two metallic uprights which communicate with the earth: they are thus discharged and collapse, again to be charged: the number of oscillations of the gold leaves affords