什么是电荷？

Charge or electric charge is the intrinsic property of a body by which it can exert an electric force on another body.

Charges are of two types: positive and negative. They are produced by either the deficiency or excess of electrons in a body, respectively.

Opposite charges attract. And like charges repel. Charges are measured in coulumbs, denoted by C.

Charge is quantized, meaning that the charge on any body is an integral multiple of the charge on electron, i.e., $-1.6 * 10^{-19} C$.

It also implies that the smallest quantity of stable charge is the charge on electron. Keep it in mind that the charge on a proton is equal to the charge on an electron but with a positive sign.

$$Q=ne$$

$Q$= charge on body

$e$=charge on an electron

$n=1, 2, 3,... or -1, -2, -3,...$

Charge is one of the fundamental characteristics of nature. It was long ago when we first discovered the concept of charge. There is something in nature having some power to attract or repel. As time goes on gradually we start to discover new and new phenomena of attracting and repulsing. We feel the necessity of categorizing such behaviors of nature and such a way we pick up ourselves with the concept of charge. There are two types of charges in nature. Positive(proton, positron etc.) and negative(electron). Like charges repel each other and unlike charges attract. The discovery of the concept of charges was the introduction of electricity and through this concept we started to solve a bunch of problems of our real world.

Now we know that all the matters are made of atoms. Atom consists with positive nucleus and negative electron. There is no compellation of nature on the behavior of electron and proton that proton must be positive and electron must be negative. Positive and negative are the name of two concepts, nothing else. You can also say that proton is negative and electron is positive. But you must have to be careful about the law that two electrons will repel each other and electron and proton will attract each other.

It is very important to understand how we have come to the point of saying like repels and unlike attracts. Suppose you have 5 charges- A, B, C, D and E. After making some experiments on these particles you have made this following table-

By combining these data, we can notice that A attracts B and C and repels D and E. The charges who are repelling by A (D and E) both express the same characteristics as A. To cite an example, let’s talk about D. D is repelled by A. Like A, D also attracts B and C and repels E. On the other hand, B is attracted by A and we notice that B expresses the opposite nature of A. Such a way we can come to a conclusion that like attracts and unlike repels.