Unit 1
The Nature of Electricity
Electricity - электричество
Ancient - древний
Amber - янтарь
Phenomenon - явление
Discovery - явление
Spark - искра
Repel - отталкивать
Attract - притягивать
Wool - шерсть
Fur - мех
Silk - шелк
To rub with smth – тереть ч-л.
To achieve - приобретать
To investigate - исследовать
Similar - подобный
To develop- развивать
Opposite - противоположный
The ancient Greek knew that when a piece of amber is rubbed with wool or fur it achieves the power of attracting light objects. Later on the phenomenon was studied, and the word electric, after the Greek word «electron» meaning amber was used.
Many scientists investigated electric phenomena, and during the 19th century many discoveries about the nature of electricity were made. It was found that if a sealing – wax rod is rubbed with a woolen cloth, and a rod of glass is rubbed with a silken cloth, an electric spark will pass between the sealing wax rod and the glass rod when they are brought near one another. Moreover, it was found that a force of attraction operates between them An electrified sealing – wax is repelled, however, by a wax rod, and also an electrified glass rod is repelled by a similar glass rod.
The ideas were developed that there are two kinds of electricity, which were called resinous electricity, and that opposite kinds of electricity attract one another, whereas similar kinds repel one another.
Unit 2
Classes of Electricity
The study of electricity may be divided into three classes or branches: magnetism, electrostatics, electrodynamics.
Magnetism is the property of the molecules of iron and certain other substances through which they store energy in the field of force because of the arranged movement of the electrons in their atoms. Electrostatics is the study of electricity at rest, or static electricity. Examples of this type of electricity are charges on condenser plates. Rubbing glass with silk produces static electricity. Electrodynamics is the study of electricity in motion, or dynamic electricity. The electricity which flows through wires for light and power purposes is a good example of latter type of electricity.
Unit 3
Electroscope
Обратите внимание на слова
Electroscope – электроскоп
Sensitive- чувствительный
To suspend- подвешивать
To induce- индуктировать
to appear- появляться
to determine- определять
to detect- определять
to consist of- состоять из
a stopper- пробка
insolating- изоляционный
to fit – подходить по размеру
a sign- знак
the same- тот же самый
to touch- касаться
unknown- неизвестный
Прочитайте слова, догадайтесь о значении этих слов без словаря.
Metal, material, instrument, opposite, negative, positive, polarity, flannel
3) Прочитайте и переведите текст:
An electroscope is a sensitive instrument for detecting small electric charges. It consists of a glass – jar closed with a stopper of insulating material in which is fitted a varnished glass – tube. A rod passes through the tube. At the top of the rod there is a metal ball or disc and at the bottom of the rod 2 pieces of gold leaf are suspended. When a charge is brought near the electroscope, a charge of opposite sign is induced on the metal electroscope, a charge of the same sign appears on the two of the gold leaves. Since, the two pieces of gold leaf now have charges of like sign they repel each other.
As an example a negatively charged glass rod is brought to the electroscope. A positive charge is induced on the ball and negative charge appears on the two pieces of gold leaf.
The polarity of a charge may be determined by means of an electroscope. We charge the electroscope negatively by touching the ball with a rod of hard rubber which is rubbed with flannel or silk. If the unknown charge is brought to the electroscope it will induce on the ball a charge of positive polarity, and on the gold leaves a charge of the same polarity as that of the unknown charge. Therefore, if the unknown charge is negative, the gold leaves will repel each other, if it is positive, they will attract.
Unit 4
An Electric Current and Current Measurement
Convenient- удобный
Unit- единица
Quantity- количество
Electrolytic dissociation – электролитическая диссоциация
Constituent element – составляющий элемент
Copper sulphate – медный купорос
To deposit – осаждаться
Anode – анод
Cathode – катод
To measure – измерять
Liquid – жидкость
Presence – присутствие
Strength – сила
To produce – производить
Property – свойство
To enter – входить
The electron is an extremely small unit, and for this reason it is not a convenient unit to use in the measurement of electric current or of quantity of electricity. The presence of an electric current in a circuit may be detected and its strength may be measured by a number of different methods. Each method is based upon some effect, which the current produces under given conditions.
One of these effects is known as electrolytic dissociation. The properties of most conducting liquids are such that when a direct current is maintained in them, the constituent elements of the liquid are separated. For example, when two copper plates are dipped in a solution of copper sulphate and a direct current is maintained in a liquid entering at one plate, the anode, and leaving at the other, the cathode, metallic copper leaves the solution and is deposited on the cathode.
Unit 5
Capacity
Capacity- мощность
To receive – получать
Amount – количество, предел
definition – определение
to increase – увеличиваться
artificially – искусственно
to spread – распространяться
uncharged – незаряженный
to depend upon - зависеть от
to raise – поднимать
to remain – оставаться
arrangement – приспособление, механизм
When two insulated conductors, one of which is charged, are brought into contact, the charge spreads over both conductors. The uncharged conductor becomes charged. A larger conductor receives a larger part of the charge. The potential of the two conductors becomes the same as soon as they are brought into contact, but the quantity of electricity is not the same on each. The larger portion to the charge is on the larger conductor. We say that the conductors have not the same capacity for electricity. The capacity of the conductor depends upon its size.
The capacity of the conductor is measured by the quantity of electricity, which must be given to it in order to raise its potential to a given amount.
From this definition it is seen that if the capacity of a conductor increases while the quantity of electricity on it remains constant, its potential will become less.
Condenser. Any arrangement by which the capacity of a conductor is increased artificially is called a condenser.
Unit 6
Kinds of Circuit
Series circuit – последовательная цепь
Device – устройство
Branch – ветвь
To fasten – прикреплять
Common – общий
A path – дорожка
To connect – соединять
To flow – протекать, проходить
To divide – разделять
To carry – нести
Half – половина
Circuits can be divided into 4 classes: series, parallel, combination of series – parallel and network.
Series circuits are those having only one closed path for the flow of electricity. All the elements, or devices which make up the circuit are connected in tandem, one after the other, so that the end of one is connected to the beginning of the other; or, in other words, the positive terminal of one is connected to the negative terminal of another. If the series circuit is opened anywhere, the current will not flow through the circuit.
A parallel circuit is one divided into two or more branches, each branch carrying part of the current. Another way of saying the same thing is that all the elements or devices are connected so that one half of the terminals are fastened to a common point or a common conductor, and the other half are fastened to another common point, or another conductor
Unit 7