The electric field, according to elementary physical concepts, is nothing more than a special kind of material medium that arises around charged bodies and affects the organization of interaction between such bodies with a certain finite speed and in a strictly limited space.
It has long been proven that an electric field can occur both in motionless and in bodies in motion. The main sign of the presence of this type of matter is its effect on electric charges.
One of the main quantitative characteristics of the electric field is the concept of "field strength." In numerical terms, this term means the ratio of the force that acts on the test charge directly to the quantitative expression of this charge.
E = F / q pr
The fact that the test charge means that he himself does not take any part in the creation of this field, and its value is so small that it does not lead to any distortion of the initial data. The field strength is measured in V / m, which is conditionally equal to N / C.
The famous English researcher M. Faraday introduced the scientific method of graphic representation of the electric field. In his opinion, this particular type of matter in the drawing should be depicted as continuous lines. They subsequently became known as the “lines of electric field strength,” and their direction, based on basic physical laws, coincides with the direction of tension.
Lines of force are needed to show qualitative characteristics of tension such as density or density. The density of the lines of tension depends on their number per unit surface. The created picture of the lines of force allows us to determine the quantitative expression of the field strength in its individual sections, and also to find out how it changes.
Quite curious properties are possessed by the electric field of dielectrics. As you know, dielectrics are substances in which there are practically no free charged particles, therefore, as a result, they are not able to conduct an electric current. Such substances should include primarily all gases, ceramics, porcelain, distilled water, mica, etc.
In order to determine the field strength in a dielectric, an electric field should be passed through it. Under its action, the bound charges in the dielectric begin to shift, but they are not able to leave the boundaries of their molecules. The bias direction implies that positively charged ones move along the direction of the electric field, and negatively charged ones - against. As a result of these manipulations, a new electric field arises inside the dielectric, the direction of which is directly opposite to the external. This internal field noticeably weakens the external, therefore, the intensity of the latter decreases.
Field strength is its most important quantitative characteristic, which is directly proportional to the force with which this special type of matter acts on an external electric charge. Despite the fact that it is impossible to see this value, with the help of the drawing of the force lines of tension, one can get an idea of its density and directivity in space.