Прочтите и переведите текст и скажите, к какому источнику энергии относятся следующие слова infra-red rays и ultraviolet rays

1. In the decade 1860–1870, James Maxwell formulated his classical electromagnetic theory. He showed that light was a form of wave motion travelling with a speed dependent on the electric and magnetic properties of the medium through which it is transmitted. He also predicted that waves longer than those of light could exist.

2. Even before Maxwell advanced the theory that electromagnetic waves should exist, men were making use of them for other purposes besides vision. For instance, the short ultraviolet rays in sunlight provided suntans; and the heat of the sun – provided by the long infra-red rays – was often concentrated by means of a lens to start fires. After the existence of electromagnetic waves had been proved by Hertz it was discovered that they range in length from hundreds of miles down to less than a billionth of an inch. The long waves could be used to carry sounds through space; as a consequence radio was developed.

3. A more recent development, which is related to radio, is television. Not only sounds but pictures can be transmitted at a distance because of electromagnetic waves.

4. Another modern device, developed to send out electromagnetic waves and to receive the echoes when they return, is radar, since the speed of electromagnetic waves is known, the time it takes for an echo to return to the radar set can tell the operator how far away a plane is from his set. Radar is given the credit for saving Great Britain during World War II, for it warned of enemy planes. Thus James Maxwell had made discoveries that later protected his homeland. Today with radio, television, radar, and communication with outer space making use of these waves, it is easy to realize why James Maxwell is now considered one of the great scientists of all time.

2.5.3 Прочтите второй абзац и скажите, кому принадлежит доказательство существования электромагнитных волн. Расскажите об инфракрасных и ультрафиолетовых лучах, используя следующие слова и словосочетания: electromagnetic waves, the short rays, the long rays, to discover, an inch, to carry sounds, as a consequence

Прочтите последний абзац текста и скажите, каким образом научные открытия Дж. Максвелла помогли Великобритании во время второй мировой войны; обратите внимание на значения слова for

Date: 2016-02-19; view: 1251; Нарушение авторских прав