1. The problem was a very important step in the research.
a) having solved
b) solved
c) having been solved
2. If these methods appeared highly effective.
a) have combined
b) having been combined
c) combined
3. the device was put into operation.
a) tested
b) having been tested
c) having tested
4. As metals in industry in the form of alloys, they have better properties than pure metals.
a) having used
b) used
c) being used
5. the document, he signed it.
a) having shown
b) shown
c) being shown
VIII. , ed - :
1. The quality of the supplied equipment should be in accordance with the technical conditions indicated in the Contract.
2. We shall have the device repaired next month.
3. We can be very well informed.
4. They consider the work finished.
5. I have just had my car repaired.
IX. :
1. The motor gets overheated, unless cooled.
2. The operator being highly skilled and experienced, the parts made by him have usually no defects.
3. When asked, he always answers correctly.
4. Having collected all the material, he was able to write a full report on the work of the commission.
5. He read several books in English, the latest being a biography of Shakespeare.
X. :
1. , .
2. , .
3. .
4. , .
5. , .
1
1. , should would. 9-10[17][7] .
1. The engineer should know both the advantages and the disadvantages of the materials used.
2. Without mathematics there would be no science, no electronic com-puters, no conquest of space.
3. If we placed this material in vacuum, its mechanical properties would be changed.
2. , , . 21-29[17] .
1. The method used depends on the length to be measured.
2. Silicon is known to be the basic material for electronic industry.
3. Any element is characterised by a certain number of protons in the nucleus, this number being the same as the number of electrons in the atom.
4. Scientists today believe all substances to be made of one or more different kinds of atoms.
5. Unless treated this material must not be used in space technology.
3. , . 33-36[17] .
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1. Radar is used in airplane and ship navigation as well as in other fields of science and engineering.
2. The transformer is a device used for raising or lowering voltage.
3. The new plastics will be used as insulators both in electrical and electronic circuits.
4. :
a) , ;
b) , ;
c) , ?
5. , .
:
1) vacuum tube - ;
2) operating current - ;
3) transistorised circuitry -, ;
4) tunnel diode - ;
5) ring radio set - , .
Electronics
1. To separate electronics from the concepts of electricity is extremely difficult. The field of electricity is generally concerned with magnetism, light, heating and the production of electricity by generators and chemical action.
2. Electronics usually deals with the application of electricity in com-munications, in radio, television and other devices where vacuum tubes and transistors are employed. We know the vacuum tube and the transistor to be major components of various electronic devices.
3. The many disadvantages of vacuum tubes include high cost, bulky construction, high amount of operating current, limited life and high operating temperature. However the vacuum tube is ideal in many situations where electrical energy is readily available and where heat is no problem.
4. A more recent invention the transistor is known to have replaced the vacuum tube in many situations. The transistor operates on a minimum amount of electrical energy, emits very little heat and has a long life. The transistor is tiny compared to the size of the vacuum tube of equivalent energy output. This feature has permitted an electronic circuit to be so small that the electronic technician uses magnifying lenses to aid him in his circuit construction and repair.
5. Later research has revealed a device which has revolutionised the field of transistorised circuitry. A Japanese investigator, Lew Esaki, discovered a simple semiconductor class of crystal that is even more amazing than the transistor. The tunnel diode, as it is called, operates on a negligible amount of electric current, its diameter being some few thousands of an inch. With such a transistor man will be able to see telephones to be worn on wrists, pocket - size TV sets and ring radio sets.
6. Several recent developments in the field of electronics have led to better ways to communicate efficiently over long distances. The maser and the laser permit man to beam extremely coherent and concentrated energy with almost no loss of intensity. Lasers and masers are known to have been used for transmitting power, radio waves and other waves used in communication.
6. :
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Where will lasers and masers be used?
2
1. , should would. 9,10[17][8] .
1. Mention should be made that during the war the radar was being used for detecting airplanes.
2. Any explanation of how the sun generates heat by fission would have been impossible 60 years ago.
3. If we had used solar energy on a wide scale we should have found a solution to our energy problems.
2. , , . 21-29[17] .
1. The atoms are usually combined chemically into groups called molecules, these molecules being in constant motion.
2. In order to calculate the volume of any object you must measure its height, width and depth.
3. The rays passing through the object being examined produce an image on X-ray film.
4. The engineers are interested in plastics because they offer rare combination of properties found in no other materials.
5. Electrical forces seem to play a very important part in holding crystals together.
3. , . 33-36[17] .
1. As to this device it is capable to convert sunlight to another form of energy.
2. Neither plastics nor metals have all the desirable properties that the engineer looks for.
3. The structure of the atom is similar to a planetary system since electrons orbit around a central nucleus.
4. :
a) ?
b) , .
c) X-rays?
5. , , , .
:
1) Crooks tube - ;
2) an X - ray film - ;
3) forgery -;
4) strain - .
X-rays
1. The modern atomic age which we live in began because of an accidental discovery. In 1895 a German scientist named Wilhelm Roengen discovered the existence of X-rays. Many scientists had studied these rays but no one had discovered that when these cathode rays struck the glass wall of Crooks tube X-rays were created.
2. Roentgen also revealed that these X-rays could pass through solid matter and expose an X-rays film. This discovery led immediately to the use of X-rays in medicine, the use we are all familiar with.
3. Although Roentgen discovered the properties of X-rays he did not know what the rays were. He therefore called them X-rays, the X standing for their unknown nature. Today scientists know X-rays to be electromagnetic radiation of extremely high frequency and therefore of extremely short-wave length. X-rays are considered to be produced whenever rapidly moving electrons bombard any solid material. The greater the atomic weight of the material, the more plentiful the X-rays, the greater the speed of the electrons the higher the frequency of the X-rays.
4. As mentioned above X-rays were in a wide use for diagnostic purposes in medicine discovery. Industrial radiology has been discovered later particularly for inspecting welds and castings in the automobile and airplane industries. Flaws and cracks inside the metal are readily revealed due to the use of X-rays techniques. Famous paintings are often X-rayed to determine whether they are originals or forgeries.
5. Using X-rays irradiation the scientists have learnt to change structures of well-known materials such as metals, ceramics, etc. They could obtain materials of greater strength with higher melting point and particular electrical properties.
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6. Radiation is known to be a mutagenic agent. In microbiology mutation is increased by irradiation. When a large-scale production of penicillin was introduced the best strain yielded 100-200 units of penicillin. Being irradiated with X-rays, the same strain produced more than 1,000 units. Many new uses have been found for this treatment in agriculture.
6. . , :
What increase was obtained in the productivity of penicillin being irradiated with X-rays?
1.... a five-fold increase;
2.... a ten-fold increase;
3.... a hundred-fold increase.
3
1. , should would. 9-10[17][9] .
1. Without progress in the field of electronics it would be impossible to develop either energetics or automation.
2. If we used new plastics materials we should reduce the weight of artificial satellites.
3. X-ray chemical analysis should be applied when the elements to be examined differ widely in atomic number.
2. , , . 21-29 .
1. Some materials undergo chemical changes when subjected to heat and pressure.
2. There are still many problems to be solved concerning radio, radar and television.
3. To make a radioisotope generally means to change the nucleus of a stable element.
4. Matter is said to exist in four states - solid, liquid, gaseous and plasma, the latter being a hot ionised gas.
5. The energy being released during the fission of one gramme of uranium is equal to the energy produced by two and a half tons of coal.
3. , . 33-36 [16].
1. The speed of electrons is almost the same as the speed of light.
2. This metal possesses high strength due to the addition of tungsten.
3. Copper is in a wide use for cables because it is a good conductor of electricity.
4. :
) ;
b) , .
5. , .
:
1) to result from ;
2) internal combustion engine ;
3) wasted heat ;
4) scarcity ;
5) thermo-nuclear fusion .
