Question

A scientific instrument used to detect the charge on a body is known as:

Answer 1

The charge represents the presence of electrons on the surface of an object. This presence of the electrons can be detected by an instrument that is capable of recognizing the presence of the charges.

Complete step-by-step solution:
Whether a body is charged or not, or whether the presence of charge on the surface of the body is there or not, is detected by an instrument called the electroscope.
The objects used in the construction of an electroscope are metal rod, aluminum foil, the metal disc, conical flask and charged body.
The principle that an electroscope uses to detect the presence of the charge is given as follows.
At one end of a metal rod, a metal disc should be fixed and at the other end of a metal rod, the leaves of the aluminum foil should be fixed. This arrangement should be placed inside a conical flask. In order to isolate the aluminum leaves, the conical flask should be isolated using the cork to avoid the contact of air with the aluminum leaves. At this point, a charged body should be inserted inside a conical flask. When the charged body comes in contact with the metal rod, the aluminum leaves move away from each other. This happens, as the charges of the body get transferred to the leaves through the metal rod.
$\therefore$ A scientific instrument used to detect the charge on a body is known as the electroscope.

Note: The presence of air makes the aluminum leaves come in contact with each other. The method of transfer of charge through conduction is called the charging by conduction. The nature of charges on both the leaves and the charged body will be similar.