The laser today and tomorrow

1. The laser has become a multipurpose tool. It has caused a real revolution in technology.

Atoms emit rays of different length, which prevents the forming of an intense beam of light. The laser forces its atoms to emit rays having the same length and travelling in the same direction. The result is a narrow, extremely intense beam of light that spreads out very little and is therefore able to travel very great distances.

2. The most common laser is the helium-neon laser in the laser tube, containing 10 per cent helium gas and 90 per cent neon gas. At the end of the tube there is a mirror, and at the other end there is a partial mirror. The electrons get energy from a power supply and become “excited”, giving off energy as light. This light is reflected by the mirror at one end of the tube. It can only escape through the partial mirror at the other end of the tube.

3. The first laser was built in 1960. Since then scientists have developed several types of the laser which make use of luminescent crystals, luminescent glass, a mixture of various gases and finally semiconductors.

4. Having been developed at The Institute of Physics in 1962, semiconductor quantum generators occupy a special place among the optical generators. While the size of the ruby crystal laser comes to tens of centimeters and that of the gas generator is about a meter long, the semiconductor laser is a few tens of a millimeter long, the density of its radiation being hundreds of thousands of times greater than that of the best ruby laser.

5. But the most interesting thing about semiconductor laser is that it is able to transform electrical energy directly into light wave energy. The semiconductor laser opens up new possibilities of producing extremely economical sources of light.

V. Прочитайте 5-й абзац текста и ответьте письменно на следующий вопрос:

What possibilities does the semiconductor laser open?

Вариант 3.

I. Перепишите и письменно переведите на русский язык следующие предложения. Помните, что объектный и субъектный инфинитивные обороты соответствуют придаточным предложениям (см. образец выполнения 1).

1. The Sun and stars are proved to be able to produce great quantities of energy by means of certain nuclear reactions.

2. For the experiment we need several electrical devices to be connected in series.

3. Lasers are known to have found wide application in medicine.

II. Перепишите и письменно переведите на русский язык следующие предложения. Обратите внимание на перевод зависимого и независимого (самостоятельного) причастных оборотов (см. образец выполнения 2).

1. Measurements of solar radiation reaching the Earth each day make it possible to calculate the surface temperature of the Sun.

2. Having built a new automobile plant, we increased the output of cars and buses.

3. Knowledge being the most valuable wealth of our times, the information theory became of great importance for the national economy.

III. Перепишите и письменно переведите на русский язык следующие сложные предложения. Обратите внимание на перевод условных предложений (см. образец выполнения 3).

1. If the gathered data had been presented in time, the results of the experiments would have been different.

2.If you had answered six questions in the competition, you would have won the first prize.

3. It would be impossible to carry on a careful study of the process without the new device.

IV. Прочитайте и устно переведите с 1-ого по 5-й абзацы текста. Перепишите и письменно переведите 1, 2, 3, 4-й абзацы текста.

Пояснения к тексту.

1. digital - цифровой

2. to result in – заканчиваться, приводить к чему-либо

3. prospects – перспективы

Computers

1. The first machine for mathematical computation was built in 1822 by the mathematician Charles Babbage. From the description of this machine we know him to understand clearly all the fundamental principles of modern digital computers. Babbage was born in England in 1792. He taught himself mathematics so well that when he went to Cambridge he found that he knew algebra better than his teacher. Babbage constructed a model of a computer and devoted the rest of his life to developing an universal computing machine. But he was not understood by his contemporaries.

2. Two generations of engineers worked hard to construct a modern computer. Their attempts resulted in the development of computing machines which transformed the whole course of scientific achievements. If you looked at the machines which people had used up to 1946, you would notice that they were not so perfect as the ones available today.

3. Having invented computers engineers began to use them in industrial automatic processes. They are known to carry out several thousand arithmetic operation in one second. If there had been no computers space flights and many other achievements of modern science and technology would have been impossible.

4. We often hear that the increasing flood of information will be one of the problems of the 21-st century. The computers may help to solve it too.

5. As the electronic computer has opened great prospects for further development of science and technology, it may be spoken of as one of the most important inventions of our time.

V. Прочитайте 5-й абзац текста и ответьте письменно на следующий вопрос:

Why may a computer be spoken of as one of the most important inventions of our time?

Вариант 4

I. Перепишите и письменно переведите на русский язык следующие предложения. Помните, что объектный и субъектный инфинитивные обороты соответствуют придаточным предложениям (см. образец выполнения 1).

1. We know the wave theory of light to be first proposed by the English physicist Robert Hooke in 1665.

2. The crew is reported to have carried out a great deal of scientific experiments.

3. A problem to be solved by a digital computer must be expressed in mathematical terms.

II. Перепишите и письменно переведите на русский язык следующие предложения. Обратите внимание на перевод зависимого и независимого (самостоятельного) причастных оборотов (см. образец выполнения 2).

1. About 100 years ago, a French scientist Pierre Curie subjecting certain crystalline materials to pressure, observed that they produced an electric charge.

2. Having been subjected to high pressure metals become highly conductive.

3. The average height of the Ural mountains is 800 meters, the highest point being 1.500meters above sea level.

III. Перепишите и письменно переведите на русский язык следующие предложения. Обратите внимание на то, как переводятся условные предложения (см. образец выполнения 3).

1. If the service life of the instrument had been prolonged, the economic effect would have been increased many times.

2. Were the temperature increased, the velocity of the molecular motion would also be increased.

3. It would be impossible to ensure the full supply of energy without atomic power stations.

IV. Прочитайте и устно переведите с1-го по 5-й абзацы текста. Перепишите и письменно переведите 1, 2, 3 и 4-й абзацы.

Пояснения к тексту

1. tiny fraction of time – очень короткий период времени

2. data processing system – система обработки информации

3. digital – цифровой.