1) We... two types of current.
a) know b) knew c) knows
2) The number of cycles per second......the frequency of the current
a) is called b) was called c) am called
3) Alternating current.........info direct current
a) could be changed b) have been changed c) can be changed
4) An alternating current... its direction of flow through a circuit
a)changes b) change c)changed
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20.
1 Read and translate the text
1. The study of electricity began with Dr. Gilbert 2. He lived at about the same time as Galileo 3. In 1600 he wrote a book describing experiments on electricity and magnetism 4. Russia played an important part in the development of electrical science 5. In spite of difficult conditions under which the scientists and inventors had to work in tzarist Russia they discovered electrical phenomena of great importance 6. In addiotion to that Russian scientists and inventors always tried to find practical application for the phenomena discovered 7. The first work on electricity published in Russia was that written by the father of Russian science Lomonosov 8. Lomonosov was the first to find that heat, lignt and electricity are different forms of movement 9. He was also the first to find the electrical nature of some atmospheric phenomena. 10. Academician Petroff was the first scientist in the world who observed the phenomena know later as the electric arc.
2 Answer the questions
11. Russia played an important part in the development of electrical science, didnt it?
12. Did Russian scientists and inventors discover electrical phenomena of great importance?
13. Who published the first work on electricity in Russia?
14. What did Lomonosov find?
15. Was Lomonosov the first to find the electrical nature of some atmospheric phenomena?
3 Match the sides
| 1. difficult corrections | 1. |
| 2. practical application | 2. |
| 3. electrical nature | 3. |
| 4. elelctrical arc | 4. |
| 5. different forms of movement | 5. |
4 Make up the sentences
6. Lived, he, is, in, century.
7. Described, electricity, he, and, magnetism.
8. Scientists, Russian, electrical, phenomena, discovered, important.
9. Different, of, movement, forms, heat, light, and, are.
10. Petroff, arc, electric, observed, the.
5 Choose the right variant
1) He to the technical school every morning?
a) to go b) goes c) go
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2) We... to be students.
a) to want b) wants c) want
3. you like English?
a) to go b) do c) does
4 I stay at home on Sundays.
a) am not b) doesnt c) dont
5) it (shop) raining yet?
a) did it shop b) is it shopped c) has it shopped
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1 Read and translate the text
1.The first person to produce an electric current was Volta. 2. It happened in 1799. 3. He built the first dry cell. 4. It was made of a disk of copper, a layer of cloth, another disk of copper and so on for several layers of tree materials 5. The first disk of copper and the last disk of zinc were connected by means of a wire. 6. This connection produced current electricity. 7. The word volt comes from Volta, the name of the inventor. 8. Our present day cells and batteries of cells work on the same principle as Voltas dry cell. 9. Voltage means force or pressure of an electric current. 10. Amperage means amount of electricity flowing.
2 Answer the questions
1. Who first produced an electric current?
2When did it happen?
3. What did he build?
4. Where does the word volt come from?
5. What does voltage mean?
3 Match the sides
| 1. electric current | 1. || |
| 2. dry cell | 2. |
| 3.connected by means of | 3. |
| 4. voltage means force | 4. ' |
| 5. amperage means amount of electricity | 5. |
4 Make up the sentences
1. Built, he, first, cell, dry, the.
2. Comes, Volta, from, word, the, volt.
3. Produced, Volta, elelctric, an current.
4. In 1799, happened, it.
5. amount, means, amperage.
5 Choose the right variant
1)...she a teacher?
a) Am b) Is c) Are
2) They me to visit them yesterday
a) asks b) ask c) asked
3) you read this book Some days ago?
a) did b) do c) does
4) ... a pupil.
a) am b) is c) are
5)... you do for a walk after school?
a) do b) does c) did
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1 Read and translate the text
1. Electricity plays a very important part both in industry and in agriculture. 2. We use electricity as a means of transportation and communication. 3. A primitive man depended upon fire, smoke or other kind of signals to send his thoughts to his neighbour. 4. And a modern man can talk with someone in some distance. 5. In recent years electricity has made a great contribution to radio communication between the spaceships and also between the austronauts and the Earth. 6. We apply elelctricity in automation and in research. 7. Much of todays scientific research depends on the solution of different difficult mathematical problems. 8. Some of which would require days to solve by the used methods. 9. Electrically operated computers now give the answer to these problems in seconds. 10. They are very popular.
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2 Answer the questions
16. Does electricity play a very important part both in industry and in agriculture?
17. Is the electricity a means of transportation and communication?
18. What did a primative man depend upon?
19. Do we use elelctricity as the means of transportation?
20. How quickly do the computers we answers to the questions
3 Match the sides
| 1. as a means of transportation | 1. |
| 2. electricity operated computers | 2. || |
| 3.in some distance | 3. |
| 4. depends on | 4. |
| 5. radio communication | 5. '| |
4 Make up the sentences
1. Plays, electricity, very, a, role, important.
2. Use, we, a, as means, transportation electricity, of.
3. Apply, we, in, electricity, automation.
4. Computers, problems, solve, seconds, in.
5. Computers, very, popular, are, now.
5 Choose the right variant
1... your names Jack and John?
a) Am b) Is c) Are
2) We... not from Great Britain,
a) am b) is c) are
3. How much this sweater?
a) Is b) Does c) Do
4) you give me this book tomorrow.
a) shall b) does c) will
5)...he fine?
a) Am b) Is c) Are
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23
1 Read and translate the text
1. Current is a flow of electricity through a circuit 2. There are two types: a direct and alternating. 3. A direct current flows through a conducting circuit in one direction only. 4. An alternating current is a current that changes its direction of flow through a circuit. 5. Alternating current flows in cycles. 6. The number of cycles per seconds is called frequency of the current. 7. It is easy to transform a.c power from one voltage to another by transformer. 8. Transformers are also used to step down the voltage at the receiving point. 9. A.c can be changed into d.c. 10. But it is seldom necessary.
2 Answer the questions
1. What is current?
2. How many types of current are there?
3. How does a direct current flow?
4. What current changes the direction?
5. What is frequency?
