Question

An electroscope is a device which is used to find whether an object is :
A. Charged
B. Magnetic
C. Free of cracks
D. hot

Answer 1

Hint:
To proceed with the following solution of the given question, we need to primarily brush up the concept of Coulomb’s Law of attraction which states that the electric force for charges at rest has the following properties that like charges repel each other and unlike charges attract each other. Thus, two negative or positive charges would repel each other whereas a positive charge would attract a negative charge or vice versa.

Complete answer:
An electroscope is generally an early scientific instrument that is used to detect the presence and magnitude of electric charge on a body. It was the first electrical measuring instrument.
The structure and composition of a basic gold leaf electroscope is simple as it consists of a vertical metal rod from which two parallel strips of gold leaf hang down which are enclosed in a glass bottle to stay protected from and undisturbed by drafts of air.
A neat labeled diagram of neutral and charged gold leaf electroscope is provided as follows:

The working of a basic gold leaf electroscope is given as follows: When the metal rod is provided a contact with a conductive charged object, the gold leaves in the container spread apart. This is because the charge on the object is conducted through the metal rod to the leaves and since both the parts of leaves receive the same sign charge they repel each other and spread apart.

Note:
One is advised to remember that an electroscope is a device which is not just used to detect charge in objects being in contact with them, but it can also be used as a voltmeter or electrometer as it has a very high resistance or to detect cosmic radiation where electroscopes are exposed to atmosphere with cosmic radiation which will ionize air and cause a small leakage in the current.