Electroscope

Electroscope

An electroscope, also known as an electrometer, is used to detect electrical charges. It also can be used to determine whether a body is electrically charged.
The mode of operation of the electroscope is based on the fact that similarly charged bodies repel each other. If the metal rod and metal pointer are charged in the same way, the pointer deflects. An electroscope, also known as an electrometer, is used to detect electrical charge. An electroscope can be used to determine whether a body is electrically charged.
The mode of operation of the electrometer is based on the fact that similarly charged bodies repel each other.
An electroscope consists of a metal rod that is connected to a rotatably mounted metal pointer. If you touch the tip of the metal rod with a negatively charged body (Fig. 2), electrons are transferred to the tip of the metal rod. From there they are distributed over the metal rod and the metal pointer.
The metal rod and metal pointer are now negatively charged. Bodies of the same charge repel each other. Since the pointer is rotatably mounted, it is repelled by the metal rod. The pointer deflects.

The negative charge on an electroscope

If the tip of the metal rod is touched by a positively charged body (Fig. 3), electrons migrate from the metal rod and metal pointer to the positively charged body, because unequal charges attract each other. This creates a lack of electrons on the metal rod and on the pointer, ie a positive charge. Metal rod and pointer repel each other.
With an electrometer, one can only prove whether and how strongly a body is charged, but not what charge it has.

The positive charge on an electroscope

In the case of an electroscope, the pointer can already deflect if a charged body is brought close to the tip of the metal rod but does not touch it. The cause of this is the influence.

There is an

There is an electric field around the charged sphere. The moving negative electrons in the metal rod and metal pointer of the electroscope are repelled in this field. The tip of the metal rod of the electroscope is then positively charged, the metal rod and the pointer are negatively charged. Since similarly charged bodies repel each other, the pointer of the electroscope deflects.
If you remove the negatively charged sphere, the negatively charged electrons are distributed evenly over the metal rod and pointer. The pointer deflection decreases. Join Burraq Engineering Solutions to get physical and online training in Electrical Automation & Electrical Engineering

around the charged sphere. The moving negative electrons in the metal rod and metal pointer of the electroscope are repelled in this field. The tip of the metal rod of the electroscope is then positively charged, the metal rod and the pointer are negatively charged. Since similarly charged bodies repel each other, the pointer of the electroscope deflects.
If you remove the negatively charged sphere, the negatively charged electrons are distributed evenly over the metal rod and pointer. The pointer deflection decreases.