Read and translate the text. It was Newton who formulated the basic concept that light from ordinary sources is complex

LASER LIGHT

It was Newton who formulated the basic concept that light from ordinary sources is complex. By "complex" he meant that such light could be analysed into colours and the colours could be used to synthesize light.

How does laser light differ from ordinary light? In brief, it is much more intense, directional, monochromatic and coherent.

We know the light emitted by an ordinary source such as candle or an incandescent lamp to consist of uncoordinated waves of many different lengths, that is, it is incoherent and more or less white.

The scientists found the waves of laser light to be coordinated in space and time and to have nearly the same length. This coherence and chromatic purity and also intensity of laser light result from the fact that in a laser excited atoms are stimulated to radiate light before they have had time to do so spontaneously and independently. The directionality of laser light arises from the geometry of the laser. These properties of laser light suggest many uses for it both in technology and in physics. The scientists consider laser light to be different from ordinary light even when it merely illuminates a surface. The surface looks grainy and sparkles.

By means of some instruments it has become possible to examine materials and physical phenomena in new ways. Among the most interesting applications of the laser the probing of materials by the study of their scattering of light should be mentioned.

The laser is being applied to probe the internal structure and behaviour of molecules by examining the light-scatter­ing phenomena. Many investigators are working at the development of coherent light sources, those ones whose wave-length can be changed. Many amplifiers and oscillators have been constructed for this purpose lately.

Laser light is applied in many fields such as medicine, biology, industry and so on. We can say scientists made laser light serve man.

The scientists found the energy density of the image formed by a lense in a laser beam to be used to heat, melt or even vaporize small areas of any material. Laser is also used to pierce holes in diamond.

Nowadays laser can be used to cut a wide range of materials including wood and paper.

The scientists expect laser to be widely used almost every­where.

Notes on the Text:

1.in brief– коротко, кратко

2.result from the fact– происходят из-за того, что

3.light-scattering phenomena– явления рассеивания света

10. Answer the questions to the text:

1. What is the difference between laser light and ordinary light? 2. What did the scientists find out about the waves of laser light? 3. What do the properties of laser light suggest? 4. Why did it become possible to examine some materials in a new way? 6. Which is the most interesting application of laser light well known to everybody? 7. Why is the discovery of laser light so important?

11. Find the correct answer to the following question:

How does laser light differ from ordinary light?

a) The waves of laser light are found to be coordinated in space and time and to have nearly the same length.

b) The light emitted by an ordinary source consists of uncoordinated waves of many different lengths.

c) Laser light is not so intense and coherent.

d) Laser light does not differ greatly from ordinary light.

12. Open the brackets translating the Russian words into English:

1. The light emitted by an (обычным) source consists of uncoordinated waves. 2. The scientists found the wavesof laser (света) to be coordinated in (пространстве) and time, 3. Laser light is different from ordinary light even when it (просто) illuminates a surface. 4. (С помощью) some instruments it is possible to examine materials and physical phenomena in new ways. 5. (Внутренняя) structure should be examined much better.

13. Insert appropriate prepositions:

1. Laser light differs... ordinary light. 2. This differ­ence results... the fact that this light is more intense. 3.... means... some microscopes we can observe the movement of these particles. 4. This material was examined... new ways. 5. He is working... the problem of using the source of light in industry. 6. Many new instruments and devices have been built … this purpose lately. 7. This work consists... two parts, the first one having already been done.

14. Translate into English using the Objective Infinitive Construction:

1. Мы знаем, что луч лазера широко используется в медицине. 2. Мы думаем, что этот опыт был проведен ус­пешно. 3. Я предполагаю, что источник этого света будет изучен. 4. Я хочу, чтобы вы приняли участие в этом ис­следовании. 5. Я вижу, как они проводят опыты в нашей лаборатории. 6. Мы предполагаем, что конференция уже закончилась. 7. Мы считаем, что эти легкие металлы будут использованы во многих отраслях промышленности в будущем.

15. Translate the following sentences into Russian, mind the Objective Infinitive Constructions:

1. The scientists stated atoms or molecules which contain an even number of electrons to have no magnetic moment. 2. They found that gas to be oxygen. 3. We supposed this substance to have liberated heat when the temperature had been greatly raised. 4. This scientist states laser light to be different from ordinary light. 5. The scientists proved this substance to be an element. 6. After a number of tedious experiments they made the substance dissolve. 7. Pressure caused ice to melt. 8. The scientists know many substances organic as well as inorganic to be stable in the presence of visible light.

16. We are sure you to know the answers the questions that follow:

1. What country was the first to have pioneered lasers? 2. What did Siberian scientists contribute to the application of laser? 3. What way is laser applied in medicine? 4. What spheres and industries is laser used nowadays? 5. How is laser employed in ecology?

Дата добавления: 2014-10-31