What is electrostatic induction?

Returning to school

Before answering the question, what is electrostatic induction, it is necessary to determine what exactly is meant by the term "conductor". Although even at school physics lessons, whole topics are devoted to this, a person who does not directly face repair and maintenance of electrical equipment, after some time, often loses unused knowledge. This is quite natural, therefore, let us recall the main points, without understanding which it is impossible to explain what electrostatic induction is.

Moving charged particles in conductive materials

Let us imagine that a dry wooden block is included in the rupture of an electrical circuit consisting of an ammeter, a resistor and an electromotive force source (EMF) . The arrow of the measuring device will remain on the number "zero". But if a tree is replaced by a metal, the ammeter will show the steady-state value of the current flowing through the chain. Consequently, depending on the resistance to the passage of current, all substances can be conditionally divided into three large groups - conductors, dielectrics and semiconductors. The most famous representatives of the first group are solid metals.

Conductor and field strength lines

If a metallic uncharged sample is placed in an electric field, then an ordered and directed motion of free carriers of electric charge, more commonly known as current, will appear in it. The vector of the lines of field intensity and the directivity of the current are opposite. In metals, the conductivity is due to the movement of electrons. Since the sample is not part of a closed circuit, in it under the action of the field there will be a redistribution of free charge carriers: on the one hand, electrons will gather, forming a negative potential, and on the other, their defect is formed, that is, a positive sign. This phenomenon is caused by the action of an external electric field and is called "induction". It can also be said that electrostatic induction is a phenomenon of redistribution of charge carriers caused by an electric field. It is worth noting that the effect on the conductor has a magnetic field. Thus, the flux of magnetic induction, penetrating the conductive material, creates in it an induced current. Also as a result of magnetization, summation of the induction of the material from the side of the external field and the resulting internal field occurs. The term "full induction" just denotes this amount.

Interaction of fields

A separate field arises around each charge concentration (+ and -) from the edges of the conductive material. It interacts with the external, and is directed against it. Redistribution causes a decrease in the field of charges, this occurs until its strength in the conductor itself becomes zero. In addition, the charge concentration distorts the lines of external field strength in such a way that they become perpendicular to the material. Earlier, we specifically indicated that it was an unloaded conductor. Electrostatic induction is characterized by the fact that although the distribution of charges occurs in a conductor that has entered the electric field, it remains uncharged.

Features

Since charges tend to occupy the most extreme positions, they are located on the surface of the sample. Even in the presence of an internal empty space, in the end, the field inside tends to zero. This allows you to organize effective protection of sensitive devices from external electromagnetic fields. The "protected" object is placed inside the conductor sphere (the metal grid also fits): the induced charges accumulate on its surface, form its own field, which balances the external effect inside the sphere.