1. What is the text about? 2. What do we call ‘cold light’? 3. What are luminofores? 4. What kinds of luminofores do you know? 5. How are luminofores used in the production of luminescent lamps? 6. What radiation may be discovered and observed by means of luminofores? 7. Does luminescence find any application in medicine? 8. What is the most widely used method of generating light? 9. What is called electroluminescence? 10. Is this a direct transformation of electrical energy into light?
Exercise 3 Translate and memorize the following expressions from the text.
Visible light to absorb ultra-violet rays, fast-moving electric charges, to transform energy, certain components of oil, inorganic crystallized substance, small quantities, luminescent lamps, mercury vapours, invisible ultra-violet radiation, to absorb rays, a luminous screen, fast-moving elementary particles, elementary particles, biological compounds, to turn power into light, method of generating light, phenomenon of incandescence, practical importance, proper conditions, direct transformation.
Exercise 4 Find synonyms among the following words.
Receive (v), substance (n), transform (v), absorb (v), turn into (v), method (n), argue (v), compound (n), component (n), put together (v), final (adj), quantity (n), use (v), tube (n), find (v), get (v), matter (n), convert (v), suck in (v), transform (v), way (n), dispute (v), mixture (n), part (n), make up (v), terminal (adj), amount (n), apply (v), pipe (n), discover (v).
Exercise 5 Write a summary of the text, presenting the content of each paragraph in 2-3 sentences. Use the expressions:
The main idea of the text is … The text deals with the one of the most important (urgent) issues … Much attention (consideration) is given to (classification, description) … It focuses on the matter of … The text gives an overview of … The text is mainly concerned with … The aim of the survey is to show (demonstrate, find) … Particular emphasis is given to the analysis of… The text gives a detailed analysis of (reports on) … To sum up … In conclusion …
Индивидуальное задание для студентов заочного отделения к курсу
«Английский язык»
Вариант № 21/3c
Exercise 1 Read the text and translate it in written form.
Accurate Time
(1) All the world lives by the ‘earth time’ or ‘star time’ as the astronomers call it. It means that our clocks are timed according to the earth’s rotation, for the turning earth is the master clock by which all other clocks are set.
(2) This nightly task of timing the earth’s rotation is carried out at the observatories of various countries. What an astronomer does is to determine how the star time compares with the average time of the observatory’s master clocks.
(3) To keep them as exact as possible, the clocks are protected from all outside influence. The pendulum clocks are kept underground, away from vibrations and changing temperatures. Each pendulum swings in a vacuum (that is, in a case from which the air has been pumped out), for air resistance would gradually slow down their time of swing. Each pendulum swings in a different direction, too, so that the vibration of one will not affect another.
(4) The observatories’ time signals are based on crystal clocks, since they are the most accurate. Vibrating crystals, by means of which these clocks are run, are sealed inside vacuum tubes and kept vibrating by electric current.
(5) To provide the accurate telling of time an exact measure of time is required. Such a measure is the ‘standard metre’, which is made available just as the ‘standard metre’ and other units of measurement.
(6) In today’s world not only the second but even a fraction of a second plays an important part.
(7) Our electric clocks are run by current that vibrates 60 times a second. If they vary that, they are wrong.
(8) X-ray pictures taken in one millionth of a second are now possible, to reveal what is happening inside machines operating at a very high speed.
(9) But we are chiefly interested in the time we live by, standard time, divided into hours and minutes, an hour is a man-made thing, just one-twenty-fourth part of the time it takes for the earth to make one complete turn.
(10) Today the world runs on standard time, but not so long ago most localities used their own local time. In 1884 an International Meridian Conference extended standard time to the entire world which was divided into 24 time zones. Standard time in each zone varied by one hour from the next, the time at Greenwich being taken as the zero point.
(11) In future we may use atoms to measure time, because they have within them very precise frequencies of oscillation that will prevent the clock from gaining of losing. A crystal could be adjusted to vibrate at the same rate as the atoms of some pure element.
(12) The crystal’s vibrations could be used to run a clock. Such an atom-controlled clock would keep more accurate time than the turning earth itself.
