Задание 6. Прочитайте, перепишите и письменно переведите текст.

Прочитайте, перепишите и письменно переведите текст.

Radiant Energy

For many years men used light and heat energy from the Sun and from fires but they did not understand the nature of light and heat until quite recently. Near the end of the 19th century, scientists began to think of light as waves travelling through space, somewhat the way that waves move over water.

As the problem was explored, it seemed that there should be other forms of energy, which travel in the same way that light does.

This study led to the discovery of radio waves which are somewhat like light waves. They both travel at the same speed and go out in all directions, or radiate, from one sport. They have been called radiant energy.

Radiant energy waves are unlike anything else in the Universe. Radiant energy waves need no material to carry them from place to place. This seemed so unbelievable to scientists that for years they pretended that space was filled with a substance called ether, through which light, radio and other waves of radiant energy travelled.

The number of waves which are passing a given point in a second is the frequency. In sound, we know that the greater the frequency, the higher the pitch that we hear. Experiment shows that the short, high-frequency light waves are seen as violet in colour, while the longer low-frequency waves are seen as red in colour. Some radiant energy waves, such as X- rays, are so short and have so high frequency that they cannot be seen at all. Others, such as radio waves, are so long and have so low frequency that you do not know they are present. Scientists learn about them only by experimenting and using sensitive instruments.

It is known that a current in a wire produces a magnetic field about it. If the current goes back and forth, or oscillates, a wave is set up which moves through space with the speed of light. These are radio waves. They have all the properties of other waves of radiant energy.

Radio broadcasting stations, television studios, radar sets and signals from satellites all depend upon radiant energy waves for their operation.

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