II. Ответьте на следующие вопросы, используя полученные знания.

1) What is electricity?

2) Can you prove that electricity is essential for our life?

3) What is a conductor? What materials are good conductors?

4) What material is called an insulator? Give some examples.

5) Can you explain the difference between a conductor and a superconductor?

6) What materials are the best superconductors?

7) What scientists worked in the field of superconductivity?

8) What non-traditional sources of energy can be used nowadays?

9) Which of them do you consider to be the most efficient one? Why?

III. Переведите данные предложения на английский язык, используя инфинитивные конструкции "сложное дополнение" и "сложное подлежащее".

1. Известно, что работа многих приборов основана на специфических свойствах электричества. 2. Мы знаем, что электричество имеет много преимуществ в использовании. 3. Полагают, что сверхпроводимость была открыта голландским физиком Оннесом в 1911 году. 4. Оказывается, сверхпроводимый материал может быть возвращён в обычное состояние. 5. Учёные полагали, что этот материал является хорошим проводником. 6. Пластик и резина считаются хорошими изоляторами для покрытия проводов. 7. Работа учёных Ландау и Гинзбурга позволила им представить модель, которая объясняла природу электромагнитных свойств сверхпроводников. 8. Кажется, эти студенты сейчас изучают проводимость разных металлов. 9. Вы видели, как наш профессор проводил эксперимент с медью?

SECTION 3: BRANCHES OF ELECTRICITY. ELECTRIC MACHINES

UNIT 1: Nature of Electricity

Text 1A

Ø Read and translate the text, using the given vocabulary. Learn the words by heart.

constitution	строение
matter	вещество
to be composed of	состоять из
to be made up of	состоять из
nucleus	ядро
charge	заряд
to revolve	вращаться
tremendous	огромный
speed	скорость
hydrogen	водород
terminal	клемма
equal	равный
outer	наружный
potential difference	разница потенциалов
toward	по направлению к
circuit	цепь
magnitude	величина
rate	ход, скорость

Ø Check pronunciation of the following words:

nucleus, hydrogen, surround, equal, proton, neutron, fewer, charge, closely, outer, cause, toward, apply, higher, naturally, migrate, circuit, magnitude, ease, unless.

Nature of Electric Current

In the modern conception of the constitution of matter it is composedof atoms. The atom is made up of a positive nucleus surrounded by negative chargesof electricity, called electrons, which revolve about the nucleus at tremendous speeds.The nucleus consists of a number of protons, each with a single positive charge, and, except for hydrogen,one or more neutrons, which have no charge. The atom is neutral when it contains equal numbers of electrons and protons. A negatively charged body contains more electrons than pro­tons. A positively charged body is one which contains fewer electrons than its normal number.

When the two ends of a conductor are connected to two points at different potentials, such as the terminals of a bat­tery,we say that there is an electric current in the conductor. What actually happens?

The conductor has equal numbers of positive and negative charges in its atoms, and we want to know how the charges can be made to produce a current. The atoms in metals are packed so closely that they overlap to some extent, so that it is comparatively easy for the outer electrons to pass from one atom to another if a small force is applied to them. The battery causes a potential difference between the ends of the wire,and thus provides forces that make the negative electrons in the wire move toward the point of higher potential. This electron flow toward the positive electrode is the electric current. Naturally materials differ considerably in the ease with which electrons can be made to migrate from atom to atom.

The current will not flow unless there is an electric cir­cuit.The magnitude of the current depends simply on the rateof flow of electrons along the conductor.

Note:

they overlap to some extent – они взаимно проникают в какой-то мере.

Exercises

I. Make sure that you can translate and pronounce the following words correctly:

заряд, водород, цепь, применить, нейтрон, по направлению к, наружный, вызывать, равный, величина, отличаться, лёгкость, меньше, окружать, перемещаться, огромный.

II. Get ready to answer the following questions:

1. What is an atom? 2. What does the nucleus consist of? 3. When is the atom neutral? 3. What is a negatively charged body? 4. What is a positively charged body? 5. What is the proportion of positive and negative charges in the conductor's atoms? 6. What makes the negative electrons in the wire move toward the point of higher potential? 7. What is an electric current? 8. What does the mag­nitude of the current depend on?

III. Fill in the missing words:

1. The atom is made up of a positive … surrounded by negative charges of electricity. 2. The atom is neutral when it contains … numbers of electrons and protons. 3. A negatively charged body contains … electrons than protons. 4. When the two ends of a conductor are connected to two points at … potentials, such as the terminals of a battery, we say that there is an electric … in the conductor. 5. The current will not flow unless there is an electric … . 6. Naturally materials differ considerably in the … with which electrons can be made to migrate from atom to atom. 7. The magnitude of the current depends simply on the … of flow of electrons along the conductor.

IV. Form sentences using the following word combinations:

surrounded by negative charges of electricity; a negatively charged body; from negative to positive; from one atom to another; a number of protons; a single positive charge; equal number of electrons and protons; move toward the point of higher potential; to differ in the ease.