2. Переведите словосочетания на русский язык:
a) wire strength; semiconducting material; air insulator;
b) changing strength — changed resistance; insulating materials — insulated conductors; heated brushes — heating sources.
c) highly conductive copper wire; parallely connected circuit elements; any value of resistivity; rather low melting point
d) copper wire; power plants; electric cable; metallic cable; metallic circuit; metallic conductor; insulated conductor; insulated circuit of transmission line; thick wire; thick cables.
3. Соотнесите предложения
1. The resistance of a conductor depends on its material.
2. Materials change the value of resistance with change in their temperature.
3. Different materials also have different melting points.
4. Good conductors, like the metals copper, silver, and aluminium have a very little resistance.
5. Non-conductors, like glass, wood and paper have a very high resistance.
6. Resistance of conductors and their resistivity have different units.
7. The unit by which resistance is measured is called the ohm.
8. According to their conductivity all materials are divided into conductors, insulators and semiconductors.
9. Conductors allow electricity to pass through them, insulators do not.
10. Conductors are materials having a very high conductivity.
a) Хорошие проводники, такие как медь металлов, серебра и алюминий имеют очень небольшое сопротивление
b) Непроводники, как стекло, дерево и бумага имеют очень высокое сопротивление.
c) Сопротивление проводников и их удельное сопротивление имеют разные единицы измерения.
d) Сопротивление проводника зависит от его материала.
e) По их проводимости все материалы делятся на проводники, изоляторы и полупроводники.
f) Различные материалы также имеют разные температуры плавления.
g) Проводники позволяют электричеству пройти через них, изоляторы нет.
h) Проводники являются материалами, имеющие очень высокую проводимость.
i) Материалы изменяют значение сопротивления с изменением их температуры.
j) Единица измерения, с помощью которого измеряется сопротивление, называют Ом.
4. Дополните предложения
1. Materials with low resistivity (copper, aluminium ) …
2. Materials with high resistivity (nichrome) …
3. Electric power ….
4. The term "Semi-conductors" means "half-conductor", …
5. While the conductivity of metals is very little influenced by temperature, …
6. Photocells made of semi-conducting materials ….
7. Semi-conductors are determining the progress of ….
8. A cable consists of …..
____________________________________________________________________________________
a) is generated at power plants.
b) are used to produce wire.
c) that is, a material whose conductivity ranges between that of conductors and non-conductors or insulators.
d) are capable of transforming ten per cent of sunray energy into electric power.
e) radio engineering, automation, chemistry, electrical engineering and many other fields of science and
technique.
f) a number of wires put together
g) is used to produce heaters.
h) the conductivity of semi-conductors increases sharply with heating and falls with cooling.
5. Составьте предложения
1. Thick, electric, carry, power, over, distances, long, wires.
2. An, current, electric, is, a, of, flow, electricity.
3. There, are, kinds, two, of, positive, electricity, and, negative.
4. Like, repel, charges, unlike, attract, charges.
5. The, magnetic, will, poles, repel, if, are, both, poles, , North, or, both, South, are, poles.
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