Few people know that radiation of an electromagnetic nature permeates the entire Universe. Electromagnetic waves occur during its propagation in space. Depending on the frequency of the waves, they are conditionally divided into visible light, the radio frequency spectrum, infrared ranges, etc. The practical existence of electromagnetic waves was proved experimentally in 1880 by the German scientist G. Hertz (incidentally, the unit of frequency was named after him).
From the course of physics it is known that the magnetic field is a special type of matter. Despite the fact that only a small part of it can be seen with vision, its influence on the material world is enormous. Electromagnetic waves are a sequential propagation in space of interacting vectors of magnetic and electric field strengths. However, the word "distribution" in this case is not entirely correct: it is rather a wave-like perturbation of space. The reason for generating electromagnetic waves is the appearance in space of an electric field that changes over time. And, as you know, there is a direct connection between electric and magnetic fields. It is enough to recall the rule according to which a magnetic field is present around any current-carrying conductor. A particle affected by electromagnetic waves begins to oscillate, and since there is movement, then there is radiation of energy. An electric field with the speed of light is transmitted to a neighboring particle at rest, as a result, a field of an electric nature is again generated. And since the fields are interconnected, magnetic appears next. The process spreads like an avalanche. In this case, there is no real movement, but there are particle vibrations.
Physicists have been considering the possibility of the practical use of this type of oscillation for a long time. In the modern world, the energy of electromagnetic waves is so widely used that many do not even notice it, taking it for granted. A striking example is radio waves, without which the operation of televisions and mobile phones would be impossible.
The process is as follows: a modulated alternating current is constantly transmitted to a metal conductor of a special shape (antenna) . Due to the properties of the electric current, an electric, and then a magnetic field appears around the conductor, as a result of which electromagnetic waves are emitted. Since the oscillation frequency is modulated, they carry a certain order, encoded information. To catch the necessary frequencies, a special-purpose receiving antenna is installed at the recipient. It allows you to select the desired frequency from the general electromagnetic background. Once on a metal receiver, the waves are partially converted into an electric current of the initial modulation. Then they arrive at the amplifying unit and control the operation of the device (they move the speaker cone, turn the electrodes in the TV screens).
The current obtained from electromagnetic waves can be easily seen. To do this, it is sufficient to expose the exposed cable from the antenna to the receiver to touch the total mass (heating battery, ground loop). At this moment, a spark jumps between the mass and the vein - this is a manifestation of the current generated by the antenna. Its value is greater, the closer and more powerful the transmitter. The configuration of the antenna also has a significant effect.
Another manifestation of electromagnetic waves that many daily encounters in everyday life is the use of a microwave. Rotating lines of field intensity cross the object and transfer part of their energy, heating it.