Electric charge definition, explanation, example and formula

Let us first clarify the basics: what is an electrical charge and what are the electrical charges?

Electric charge 

An electric charge is a physical quantity that determines the property of particles or bodies to enter into electromagnetic force interactions. 

Electric charge is a fundamental property of matter. There are two types of electrical charge: there are positive electrical charges and negative electrical charges. Electrical phenomena are based on the accumulation or movement of charges.

Positive charges are marked with a plus (+) and negative charges are marked with a minus (-). These also show certain behaviors among themselves, which we will look at.

We now take two loaded balls. A positively charged ball, and a negatively charged ball. These two attract each other:

Attract electrical charges:

Two positively charged balls repel each other:

Repel electrical charges positively

Two negatively charged balls also repel each other:

Electric charges repel negatively

Tighten and push off:

  • The same charges repel each other.
  • Unequal charges attract each other.

In chemistry and physics, the focus is always on the structure of atoms. Here, students are taught that there are protons in the nucleus of an atom and electrons in the shell. The protons are positive and the electrons are negative.

A body that has a negative effect on the outside has an excess of electrons. A body that has a positive effect on the outside, however, lacks electrons (lack of electrons). Of course, there is also a third option: the body is electrically neutral. In this case, there is the same number of protons and electrons. Let's look at this again with pictures.

Overall negatively charged body:

Overall positively charged body:

Electrically neutral body:

The smallest possible electrical charge is called an elementary charge. Every electric charge is a multiple of this elementary charge.

Formula symbols and unit:

We usually state heavy goods in kilograms. We usually give the height of a book in centimeters. How do you measure the number of loads? We do not do this in kilograms or centimeters, but in coulombs. You can easily abbreviate this with a C. The smallest charge is the elementary charge "e". It is:

e = 1.602.10-19 C

Formula charge body:

One can calculate the charge of a body with the above equation:

The following applies:

"Q" is the amount of charge in coulombs
"N" is the number of charges
"e" is the elementary charge with 1.602 · 10-19 C

We can find an example with numbers below.

Examples of electric charge

This section presents examples of electrical charge. These examples correspond to what we often deal with in school.

Example 1:

Fill in the following blanks:

Loads of the same name ___________ one.
Loads of the same name ___________ from each other.


  • Charges of the same name attract one.
  • Loads of the same name repel each other.

Example 2:

This task is usually not dealt with in 5th grade, but only later. It should be listed here for completeness. The task: The number of loads is 6.24 · 1017. How big is the total load?


We use the formula to solve the problem.

We also know how big the elementary charge e is:

We can find the number of loads in the task. So, we calculate Q.

The total charge is therefore 0.1 C.

Questions with answers about electric charges:

In this section, we look at typical questions with answers about electrical charges.

Q: How can you prove electrical charges?

A: There are several ways and attempts to detect electrical charges:

Electroscope: An electroscope is used to detect the electrical charge on a body. It is a measuring device with a pointer. The pointer deflection is a measure of the size of the load.
Ruler and cloth: Take a plastic ruler and hang it on a thread. Now rub a cloth vigorously to charge it. This is exactly what you do with a second ruler. If you now bring both rulers together, they repel each other.
Q: What is Influence?

A: Influence is understood to mean the change in the charge distribution on a body because of the approach of a charged body. If we bring a charged body close to an electrically uncharged body, then the charged body exerts forces on the uncharged body, which leads to the movement of electrons.

Q: Can you separate loads?

A: Yes, you can separate charges by touching or rubbing. Electrons pass from one body to another. There is also charge separation through electrochemical processes. We use this for accumulators and galvanic elements.

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