What is electromagnetic induction

Education

Electromagnetic induction surrounds us everywhere.Even at this point, when you read these lines from the screen of your electronic device, the cells of the body are affected. However, it is not worth worrying about, because its intensity is so insignificant that it is only of theoretical interest. 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 is electromagnetic induction.

Let's put a simple thought experiment.To do this, we need a metal hoop ring, in which a sensitive ammeter and a low-power incandescent lamp are sequentially connected. This hoop will be a closed loop, through which an alternating current can flow. The ring itself is isolated: for example, it is concealed in a plastic shirt. The second necessary element is a long wire, through which current flows. The tension here should be higher. We place the hoop in one room, and the wire in the other. It is obvious that the ammeter in the metal ring will show zero - indeed, where does the current come from ?! Now we put 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. Miracles! After all, the electrons from the wire can not jump on the metal of the ring, since the latter, as we specifically pointed out, is insulated by a non-conductive plastic current. Let's complicate our experiment: wrap the wire on 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 make a short excursion into history.

The discovery of electromagnetic induction in 1831is attributed to M. Faraday. Ten years before, he had set himself the goal of converting magnetic fields into electrical energy and, apparently, brilliantly coped with it. Already at that time physicists knew that there are two kinds of fields - magnetic and electric. If the charge carriers move, then a magnetic field is recorded, and if stationary, then the electrostatic field. Many then assumed that the fields should be somehow interconnected, but Faraday did justify this practical experience and justify it. He moved the smaller coil inside the larger one. The conclusions of one of them were connected to the measuring device, and the other led through a constant current. The appearance of the motion of particles in the circuit is called the induced (induced) current. If the particles possessing a charge move in a directed manner, then a magnetic field appears around them. In order to induce the induction, the lines of tension of this field must cross the conducting contour. The contour itself and the field can be displaced, the result is the same. The replacement of a direct current (the Faraday experience) by a variable allows avoiding any mechanical displacements, since the generated field itself varies in time. The use of electromagnetic induction allowed the creation of electrical energy transformers. Perhaps, electrical engineering would never have reached modern heights, if there were no such devices.

What is the danger to man?Some lines of the transmission line transmit a voltage of thousands of volts. Because of this, the existing field around the wires can spread several meters. In a person caught in such an alternating field, the water molecules are oriented along the lines of tension. Long stay in such conditions negatively affects many systems of the body.

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