Electromagnetic induction surrounds us everywhere. Even at this moment, when you read these lines from the screen of your electronic device, the cells of the body are affected. However, you should not worry about it, because its intensity is so insignificant that it is of theoretical interest only. However, under certain conditions, electromagnetic induction can increase to dangerous values. As you know, human security depends, first of all, on himself. Therefore, it is necessary to have at least a general idea of what electromagnetic induction is.
Let's put a simple thought experiment. To do this, we need a metal hoop ring, into the gap of which a sensitive ammeter and a low-power incandescent lamp are connected in series. This hoop will be a closed loop through which alternating electric current can flow . The ring itself is insulated: for example, sheathed in a plastic shirt. The second necessary element is a long wire through which current flows. The voltage here should be higher. We place the hoop in one room, and the wire in another. Obviously, the ammeter in the metal ring will show zero - indeed, where does the current come from ?! Now we place the wire directly on the ring ... At this moment, if the voltage value is not too small, the arrow of the device deviates from zero. Wonders! After all, the electrons from the wire cannot jump onto the metal of the ring, since the last thing we specifically pointed out is insulated with non-conductive plastic. Let's complicate our experiment: wind the wire around the hoop. Now the arrow of the ammeter clearly indicates the presence of an electric current in the ring . The reason for this is electromagnetic induction. To explain what is happening from a scientific point of view, you will have to take a short excursion into history.
The discovery of electromagnetic induction in 1831 is attributed to M. Faraday. Ten years before, he set out to convert magnetic fields into electrical energy and, apparently, he coped brilliantly with this. Already at that time, physicists knew that there were two types of fields - magnetic and electric. If the charge carriers move, then a field of a magnetic nature is recorded, and if they are motionless, then an electrostatic field. Many then assumed that the fields should be somehow interconnected, but it was Faraday who made the practical experience confirming this and justifying it. He moved the smaller coil inside the larger one. The conclusions of one of them were connected to the measuring device, and direct current flowed through the turns of the other . The occurrence of particle motion in the circuit is called the induced (induced) current. If the particles having a charge move directionally, then a magnetic field appears around them . For induction to occur, the lines of intensity of this field must cross the conductive circuit. Both the contour itself and the field can shift - the result is the same. Replacing a direct current (Faraday experiment) with an alternating current avoids any mechanical displacements, since the generated field itself changes in time. The use of electromagnetic induction made it possible to create transformers of electrical energy. Perhaps, electrical engineering would never reach modern heights, if there were no such devices.
What is the danger to humans? Some power lines transmit voltage of thousands of volts. Because of this, the existing field around the wires can extend several meters. In a person caught in such an alternating field, water molecules are oriented along the lines of tension. Prolonged exposure to such conditions adversely affects many body systems.