The instrument used to detect a charged body is electroscope. Description of Electroscope: Take an empty jam bottle. Take a piece of cardboard slightly bigger in size than the mouth of the bottle. Pierce a hole in it, so that a metal paper clip could be inserted. Open out paper clip as shown in the figure. Cut two strips of aluminium foil about 4 x 1 cm each and hang them on the paper clip
Insert the paper clip having the strips of aluminium foil into the cardboard lid so that it is perpendicular to it. This entire device works as a electroscope. Procedure to detect a charged body ,by using a electroscope:
Charge a refill and make it touch the end of the paper clip. The aluminium foils move away from each other the reason that the strips of aluminium foil receive the same charge from the charged body through the paper clip and strips carrying similar charges repel each other and hence they move apart. This proves electroscope is useful in detecting a charged body
