What is an electroscope? Draw a labelled diagram of an electroscope and explain its working.

Electroscope is the device which is used to detect charge on a body. It is used for detecting, measuring and finding the nature of a charge. An electroscope consists of a large jar. A metal rod is fitted into the mouth of the jar with the help of the cork. At the lower end of the metal rod a pair of thin leaves of gold or aluminium is suspended. If the leaves of the electroscope diverge or open up when an object is touched, the body is charged. The extent of divergence or opening up of the leaves is a measure of the charge on the body. A body with higher charge will cause greater opening up of the leaves.