Active Words and Expressions

electromotive force, excess, far apart, free, in case, to influence, movement, to offer resistance, potential difference, provided, reason, size, to suspend, unit, unless

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Exercises

/. Translate the following sentences:

A. 1. If an e.m.f. is applied to a path, the electrons will move toward the point of higher potential. 2. If people of the past had known that lightning was atmospheric electric- ity, they would not have invented numerous stories. 3. If a wire were held against an electrified body, electricity would flow along the wire to its other end. 4У If coal were not used as fuel, we should get more valuable products.

B. 1. Were that liquid heated, it would greatly expand.

2. Were there no flow of current between A and В in any direction, then A and В would be at the same potential.

3. Were the electromotive force alternating, the current would be alternating as well. 4. Should you break the circuit, no current would flow. 5. Had they used a larger water pipe for their last experiment, more water would have passed through that pipe. 6. The current will flow around the cir­cuit unless we break the circuit in some point.

//. Translate the following sentences and define the func­tion of the word "provided":

1. These electrical devices are provided with rubber in­sulators. 2. These electrical devices provided with rubber insulators were produced at a large factory. 3. These electrical devices can work for a long time provided they are made of high-quality material. 4. The electric current flows provided there is a complete circuit. 5. Lightning did not strike the house as it was provided with a lightning conductor. 6. Ohm's law provided the possibility of determining resistance pro­vided the voltage and current were known. 7. The electrons will jump through the air forming an electric spark provided the potential difference becomes great enough. 8. The stu­dents will be able to translate difficult articles provided they have dictionaries.

Complete the following sentences:

_A.

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_{• # •}

1. If my friend comes to Moscow, we

2. _{If I had time tomorrow, I ...}

3. If my friend had not entered the institute last year, he ...

4. If I were you, I

5. If the teacher had given me the dictionary at the last lesson, I ...

6. If my brother goes to England, he ...

_B.

1. He would have done it unless ...

2. We should have gone to the country yesterday pro- vided ...

_{3. I should finish my work in time tomorrow unless ...}

4. She will answer all the teacher's questions pro- vided ...

IV. Translate the following sentences:

1. It was in 1800 that Volta first produced a continuous current. 2. It is the thermometer that measures the tempera­ture of a substance. 3. It was Lomonosov who stated that heat phenomena were due to molecular motion. 4. It is the ampere that is the unit of current. 5. It is in the Soviet Union that atomic energy was first used for peaceful purposes. 6. It was Popov who was the inventor of the radio.

V. (a) Fill in the blanks with prepositions] (b) translate the following text:

The great French physicist Ampere was an absent-minded man. One day he was waiting... his friend. The appointed hour arrived, passed and his friend did not come. As Ampere had to go ... he took a piece ... chalk and wrote ... his door: "I have gone .... I shall return ... two hours." And he went... .

He returned two hours later. While he was going upstairs he worked out a very difficult problem.

"If my friend had come ... the appointed hour," he said ... himself, "I should have told him ... this problem. I shall speak ... him ... it now. Perhaps he will be able to solve it." So when Ampere came ... his own door and saw the words written ... it, he decided that he was ... his friend's door. "Oh," said he, "he has gone...l I am very sorry! Were he ... home, we should discuss my problem." And he wrote the following words: "Very sorry that I have not found you ... home." Then he went downstairs again.

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VI. What is the English for the following Russian words and expressions?

обращать внимание; на основе чего-л.; электротехника; по этой причине; удовлетворять требованиям; совсем не трудно; тем не менее; наоборот; оказывать сопротивление; в таких условиях; происходить

VII. Put all possible questions to the following sentences:

1. The excess electrons will flow towards the point of deficiency. 2. The parallel circuit provides two or more paths for current flow.

VIII. Apply suitable adjectives to the following nouns. Model: natural phenomena

difference, spark, force, wire, factor, resistance, con­ductor, ball

IX. Form new words of the same root, define what parts of speech they are:

active, differ, ease, conductance, resist, generator

X. Describe Fig. 8.

XI. Speak on:

1. Electromotive force.

2. Resistance.

LESSON SIXTEEN

_{THE MODALITY}