Контрольная работа № 2 Вариант № 3

. Переведите предложения с модальными глаголами и их заменителями.

. We can measure voltage and potential difference with a voltmeter. 2. What instrument may we use in measuring current? 3. He will be able to draw a circuit diagram. 4. They might know safety rules. 5. He lad to remember properties of metals. 6. You must_do this work in time.

. II. Вы собираетесь строить дом. Составьте рекомендации, употребив глаголы в

повелительном наклонении:

0 make a design, to choose the right place, to work hard, not to forget about the landscape, to choose modern building materials, to calculate money

III. Перепишите и переведите письменно предложения и словосочетания, обратите внимание на многозначность предлогов.

I. We must try to bring the government down. 2. The new government promises to bring down prices. 3. How did you bring it off? 4. Our firm is bringing out a new product. 5. There are a lot of interesting places in our town. 6. We are going<on an excursion around the town.

IV. Перепишите предложения, подчеркните инфинитив и инфинитивные обороты; переведите предложения на русский язык.

1.1 can't for the weather to change. 2. I want you to tell me all you know about him. 3. I'll make him tell (he truth. 4.1 saw children cross the street when the light was red. 5.1 shall be happy to do it for you. 6. She seems to know a lot about music.

V. Определите, от каких частей речи образованы выделенные слова; переведите предложения на русский язык.

1 They are quite different. 2. What is the difference between "town" and "city"? 3. There is a lot of violence on TV now. 4. Chemistry is my hobby. 5. He is a chemist by profession. 6. The weather is very changeable this spring.

VI. Перепишите предложения, переведите их на русский язык; напишите числительные

прописью.

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1. They have 4 pairs every day. 2. He studies on the 2^nd course. 3. There are 5 flowers in the vase. 4. In his garage there are 3 cars. 5, The diagram of voltaic cell is number 9. 6. Each eel! produces an emf of 1,5 volts.

VII. Прочитайте текст, переведите его письменно и составьте план.

Electrical Measuring Units and Instruments

Any instrument, which measures electrical values, is called a meter. An ammeter measures the current in

amperes. The unit is named after Andre Marie Ampere, a French scientist, who discovered a great number

of facts about electricity over a hundred years ago.

A voltmeter measures the voltage and potential difference in volts. The volt is named after Alessandro

Volta, an Italian scientist.

Two things determine the current in a conductor, the voltage across the conductor and the resistance of the

conductor. Every material object offers some resistance to the flow of an electron current through it. Good

conductors like the metals, copper, silver and aluminum offer very little resistance, while nonconductors

such as glass, wood and paper offer a very high resistance. The unit by which resistance is measured is

called the ohm. The resistance in practice is measured with ohmmeter.

A wattmeter measures electrical power in watts.

Very delicate ammeters are often used for measuring very small currents. A meter whose scale is calibrated

to read a thousandth of an ampere is called amilliammeter. One whose scale is calibrated in millionth of an

ampere is called a micro ammeter or galvanometer.

Whenever an ammeter or voltmeter is connected to a circuit to measure electric current or potential

difference the ammeter must be connected in series and the voltmeter in parallel.

As it is shown on the picture, the ammeter is so connected that the entire electron current passes through it.

To prevent a change in the electron current when such an insertion is made, all ammeters must have a low

resistance.

Most ammeters therefore have a low resistance wire, called a shunt, and connected across the armature

coil.

A voltmeter, on the other hand, is connected across that part of the circuit for which a measurement of the

potential difference is required. If the potential difference between the ends of the resistance R is wanted,

the voltmeter is connected in parallel.

Wordlist

electrical current

to measure

voltage

potential difference

conductor

resistance

electrical power

to calibrate

to connect in series (in parallel)

a shunt

электрический ток

измерять

напряжение

разность потенциалов

проводник

сопротивление

сила тока

градуировать

соединять последовательно (параллельно)

переключение

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