Charging of Bodies

A charge is an elementary property of an object like mass. The charge is the fundamental source of the electric field, electric force, and electromagnetic wave. In 600 BC, the amber effect was discovered, which was explained by the famous Greek mathematician Thales of Miletus. Ambar, when rubbed with fur, attracts hair like light objects. When amber is rubbed for a long time, it creates an electric spark. After some time, due to the triboelectric effect, the charge gets shared with other substances and sparks. 

The process by which a neutral body converts to a charged body is known as electrification. A neutral body loses or gains its valence electron and converts to a charged body by electrification. Charges are of two types: positive and negative charges. A neutral body has the same number of protons and electrons. The protons are bound in the nucleus of an atom and do not move, but the electrons present in the valence shell are moved from the object when they observe some energy. This is the same energy that attracts the electron by the nucleus. So basically, the transformation of electrons causes charging. In this chapter on the charging of bodies for class 12, we will first discuss the type of charge and then the type of process charging of bodies.

Positive charge: 

The minimum energy gain by the valence electron to jump or move out from the valence shell is known as the work function. With this energy, the electron moves out from the object. Its neutrality breaks and the negative charge decreases, so the body is said to have a positive charge because the number of protons is more than the number of electrons.

Negative charge:

During the time of electrification, the electron moves from one object and goes to another body. The number of electrons increases in that body, and the proton-electron ratio gets unbalanced. The excess amount of electrons makes the body have negative charges.

Type of electrification:

By some process, the valence electrons of the object get transferred, and the body gets charged. There are many methods for charging bodies. Three main methods or processes are friction, conduction, and induction.

Charging by friction

The unbalance of the number of protons and electrons created in a body by rubbing two neutral bodies with each other is called charging by friction. In this process, one body loses its valence electron and acquires a positively charged body, and another body that has gained electrons is converted to a negatively charged body.

All the body does not get charged; only the insulators are converted to charged bodies when rubbed with each other. Because the addition of electrons doesn’t move inside the body, it is present on the surface of the body. This charge remains to rest, does not move, and produces static electricity. The body with a low work function value gets a positive charge and the body with a high work function gets a negative charge. The triboelectric series gives us the idea about which body will be under which charge. In the series, the body which will come first gets negatively charged, and the body that comes later gets positively charged. An example of charging by friction is

1.  Rubbing the ebonite rod with fur, the fur gets negatively charged and the rod gets positively charged.

2. Rubbing a glass rod with silk, the glass rod lost some electrons from positively and the silk gained some electrons to form negatively charged.

3. Rubbing plastic comb with dry hair gets attracted to the water flow line.

Charging by conduction:

The process by which an uncharged body gets charged by simple contact with a charged body is known as charging by conduction. In this process, when the uncharged body contacts the charged body, some extra amount of electrons get moved from the charged body to the uncharged body to make the body negatively charged. This process of charging is generally seen in conductors like substance metal. Both the bodies get the same type of charging in this method. According to the conservation of charge principle, the total charge of the charged body gets an equal charge distribution among these two bodies. If two equal amounts of opposite charge bodies come in contact, the two bodies get a neutral charge.

Charging by induction: 

The process by which an uncharged body is getting charged by simply bringing it close to a charged body is called charging by induction. In this process, direct physical contact is not necessary. In this method, the induction process takes place. When an uncharged body gets close to a charged body, the neutral uncharged body gets a charge so that the polarity of the two charges becomes opposite. A common example of charging by induction is when we rub a plastic comb on dry hair, the plastic comb gets charged. This charged comb will attract some tiny paper pieces. Here the uncharged paper pieces get the opposite charge of the comb with no actual physical contact.

Effect of charge on the mass of the body:

The neutral body has an equal number of protons and electrons. In a positively charged body, the number of electrons decreases; as a result, the mass of the body decreases because electrons have some mass. In a negative charge, the number of electrons is more compared to the number of electrons in a neutral charge body. Therefore the mass of the negative charge is more than the neutral charge body.   

Conclusion

The transformation of electrons makes a body charged, and this transformation of the electron is done through several processes like charging by friction, charging by induction, charging by conduction. By charging, the mass of the object changes. Sometimes mass decreases ( in positive charge), and sometimes it increases ( in negative charge).  Charging of the body is important due to this body’s electrical and electronics bodywork. It is also essential in our daily lives to charge our bodies.