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Файл:Английский язык для обучающихся по энергетическим специальностям. Учебное пособие.pdf
Exercises
The Subjective Infinitive Con-
1. He is supposed to work at this plant.
The Objectiv e Inf initiv e Construc-
1. We suppose him to work at this plant.
1 2 3
4
Professor Rihma n
-was observed
-to have started
to attract and to
-by man of 25 cen-
for Moscow on
by a stroke of
struction
tion
2. She seems to know English well.
2. I saw the water boil.
1. Translat e the following sent ences and define th e infinitive cons truc-
tions.
1. Lightning was proved to be a discharge of electricity. 2. The reader is
certain to kno w that alternating vo ltage can be increase and decr eased. 3. Heat
is known to be a form of energy. 4. We know the electrons to flow from the
negative terminal of the battery to the positive one. 5. This scientist is said to
have been working on the problem of splitting atoms. 6. I heard this instrument
meet the industrial requirements. 7. The s tudents saw the th ermometer mercury
fall to the fixed point. 8. Coal is considered to be a valuable fu el. 9. We know
many articles to have already been written on that subject.
2. According to the models given below form sentences combining
suitable parts of the sentence given in Columns 1, 2, 3, 4.
Model A: The current is known to consist of moving electrons.
Amber
Lomonosov
Electrical effects
The Fahrenheit
-is known
-is said
-is known
-are known
-to have been observed
-to have been kill ed
hold
-to be used
turies ago, or so.
foot.
-minute, light objects after rubbing.
-in Englishspeaking countries.
-
scale
lightning.
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Model B: We know lightning to be a discharge of e l ectricity.
1 2 3
4
We know
-Galileo
-to be
to have greatly
-positive and negative
-the charges
-the electric current
-alternating current
-the Russi an scientists
-static electricity
-to have invented
-to flow
-to produce
-to have been
contributed
-important effects
-an air thermometer
-first in one direction and
then in another
-to the science of electricity
-the only electrical phenomenon observe d by man.
3. Translate the following sentences using the infinitive.
1. Чтобы быть хорошим инженером, необходимо много читать и учиться. 2. Пирометр используется для измерения температуры горячих металлов. 3. Человек научился расщеплять атомы для того, чтобы получить
большое количество энергии. 4. Ученые пытаются решить проблему, связанную с новыми явлениями электричества. 5. Громоотвод – это металлическое приспособление для защиты зданий от молний. 6. Проводить опыты с атмосферным электричеством было очень опасно в то время. 7. Намагнитить предмет – это значит поместить его в поле магнита.
4. Make up questi ons and answer them. Work in pairs.
1) if electricity is a form of energy;
2) if there are two types of electricity;
3) if alternati ng voltage can be increa sed and decreased;
4) if Franklin made an important contribution to the science of electricity;
5) if Ampere d etermined the diff erence between the cur rent and the static
charges;
6) If the electric current can flow through liquids and through gases;
7) if the electrolytes change greatly when the current passes through them;
8) if a negatively charged electron will move to the positive end of the
wire.
52
5. Explain why.
1) static electricity cannot be used to light lamps, to boil water, to run elec-
tric trains and so on;
2) voltage is increased and decreased;
3) the UNIT of electric pressure is called the Volt;
4) students must learn English;
5) the flow of moving el ectrons is a form of the electr i c current;
6) Ampere was wrong as to the current direction;
7) the current is said to flow from the positive end of the wire to the nega-
tive end.
6. Define the meaning of the following words.
battery, alter nat in g cur ren t, di rect cur ren t, stat ic el ectr ici ty, el ectri c current,
wire, laboratory, terminal, electron
7. The following statements are not true to fact. Correct them.
1. Electrons flow from the positively char ged termin al of the bat tery to the
negatively charg ed terminal. 2. Ampere supposed the current to flow from the
negative pole to the positive. 3. Static electr icity is used for practical pu rposes.
4. Static electricity is not very high in voltage and it is easy to control. 5. To
show that the charges are unlike and opposite Franklin decided to call the
charge on the rubber positive and that on the glass negative. 6. Galvani thought
that electri city was generated because of the co ntact of the two dissimilar metals used. 7 . Volta took gr eat i nt erest in atmos ph eri c electr ic it y and b egan t o carry on similar exp eriment s. 8. The direct current is known to flow first in one direction and then in the opposite one. 9. The dir ect current used for p ower and
lighting purposes is assumed to go through 50 cycles a second.
8. Give headings to each paragraph of the text.
9. Put two questions to each paragraph of the text. Ask your partner to
answer them.
10. Give an abstract of the text.
53
PART III. MATERIAL FOR READING PRACTICE
complete |kəmˈpliːt| – полный, за-
to supply |səˈplʌɪ| – снабжать, пи-
generally speaking – в общем, в це-
in short – короче говоря
conductor |kənˈdʌktə| – проводник
cable fault |fɔːlt| – повреждение
cable |ˈkeɪb(ə)l| – кабель
insulator |ˈɪnsjʊleɪtə| – диэлектрик,
switch – выключатель, переключа-
so far |ˈfɑː| – до сих пор, пока
open circuit |ˈsəːkɪt| – разомкнутая
indeed |ɪnˈdiːd| – на самом деле
closed circuit – замкнутая цепь
resistance |rɪˈzɪst(ə)ns| – сопротив-
series|ˈsɪəriːz| circuit – последова-
feature |ˈfiːtʃə| – черта, характери-
short circuit – цепь короткого за-
electrical |ɛndʒɪˈnɪərɪŋ| engineering –
UNIT 10. ELECTRIC CIRCUIT
Vocabulary
конченный
лом
тель
цепь
тать
в кабеле
изолятор
ление
тельная цепь
мыкания
стика
электротехника
The purpose of the following article is to deal with the properties of the
electric circu it. But what do es t he ab ov e ter m real ly mean? We k no w th e cir cu it
to be a complete path which car ries th e curren t from the s ource of supply t o the
load and then carries it again from the load back to the source.
Generally speaking, the current may pass through solid conductors, liq-
uids, gases, vacuums or any combinations of these. It may flow in turn over
transmission lines from the power station, through transformers, cables and
switches, through lamps, heaters, motors, and so on, – back through other
switches, cables, transformers and transmission lines to the generator in the
power station.
54
There are many k ind s of cir cuit s, su ch as: op en ci rcui ts , closed circuit s, se-
ries circuits, parallel circuits and short circuits.
If the circuit is broken or, as we generally say, “opened” anywhere, the
current stop s everywhere. Hence, we br eak the circuit when we s witch off our
electric devices.
The path along which electrons travel must be complete or no electric
power can be supplied to the load from the source. Thus, we close the circuit
when we switch on our electric lamp.
A simple electric circuit is illustrated in Fig. 4. In this figure a 4-cell battery has been used, the switch being in an open position. If the switch is in
closed posit ion, a curr ent will flow ar ound the cir cuit in the di rection sho wn by
the arrows.
Fig. 4. A simple electric circuit
To underst and the difference between t he following circuit conn ections is
not difficult at all. When electr ical devices are connected so that the current is
not divided at any point, they are said to be connected in series. Under such
conditions, the current flow is the same in all parts of the circuit, as there is only
a single path along which it may flow. Quite the opposite, the parallel circuit
provides two o r more paths for th e passage of curren t. The circuit is divided in
55
such a way that part of the circuit goes through one path and part through another.
We produce a sh ort circuit or , as we sometimes cal l i t , t h e “ short” when w e
allow the current to return to the source of supply without control and without
doing the work that we want it to do. In short, this phenomenon mostly results
in cable fault and wire fault while under certain conditions it may even cause
fires.
It is interesti ng to note that so me substances like metals, for example, co nduct electri ci t y wi t h eas e; on the contrary, o t hers, such as rub ber, do not allo w it
to move freely. Thus, we obtain conductors and insulators, there being a
marked difference between them, of course.
So far nothing was said about conductance, that is, the conductor’s ability
to pass electr ic char ges. I t appear s to d epend on f our thing s, namel y: its size, it s
length, the kin d of material to be used, and its temperature.
It is not difficult to understand that a large water-pipe can pass much more
water than a small one. We equally expect a large conductor to carry current
more readily than a thinner one. Fig. 5 illus trates this f eature better than words
alone! Indeed, we see that th e larger t he wire, the g reater is i ts conduct ance because electricity meets less resistance then.
Fig. 5. Comparing water flow and current flow
56
It is quite u nderstandab le too th at to flow thr ough a shor t conductor is certainly easier for the current than through a long one, in spite of their being made
of similar materials. Hence, the longer the wire, the greater is its opposition,
that is resistance, to the passage of current.
There is a great difference in the conductance of various substances. For
example, almos t all metals are s upposed to conduct current. Nevertheless, co pper appears to carry the current more freely th an iron, silver conductin g better
than copper . It is therefore s aid to have a greater conductance t han copper. The
reader probably remembers that insulators also differ in their insulating properties.
As to temperature, we are familiar with the following feature. As the temperature rises, opposition to the passage of current increases as well. Hence,
conductance depends on the temperature of the wire.
It is quite wro ng to th i nk that conduct ing mater i al s ar e t he only materials t o
play an impor tan t part in elect ri cal engin eeri ng . As a matte r o f fact, to meet o ur
everyday power requ irements , we are certain to need both conductors and insulators.
Exercises
1. Translat e the follow ing senten ces and def ine the fun ctions of th e in-
finitive.
1. The current is known to flow when the circuit is complete.
2. To stop the flow of c ur rent is to break the circuit in some point.
3. Copper and silver a re considered to be the best conductors in electricity.
4. Various switches are generally used to open or to close the circuits.
5. Ampere supposed the current to flow from the positive pole of the
source to the negative pole.
6. It is quite possible to generate a.c. and then tra nsform it into d.c.
7. Yablochkov was the first to apply a.c. in practice.
8. A battery is the simplest device to produce direct current.
9. We know the circuit to be a path of an electric current.
10. We may expect a short circuit to result in wire fault and cable fault.
57
2. Answer the following questions.
1. What do we deal with in this article?
2. What is an electric circuit?
3. What kinds of circuits do you know?
4. When is the “short” produced?
5. What feature of the conductor is illustrated in Figure 2?
6. What does conductance depend on?
7. What do we mean by the term “short circuit”?
8. What does the term “closed circuit” mean?
9. Who deter mined the d if fer ence b etw ee n t he el ectr ic cur ren t an d t he s tat-
ic charges?
10. Why does the curre nt f low when the circuit closed?
3. Define the meaning of the following words.
Circuit, ele ctron, conductor, insulator, switch, current, conductance.
4. Compare.
1. Conductors and in sulators.
2. Closed circuits and open circuits.
3. Series circuits and parallel circuits.
5. Ask and answer questions.
1. If heat is a form of energy.
2. If all substances are made up of molecules.
3. If the molecules are travelling in various directions in a substance.
4. If the circuit is a complete path which carries the current from the
source and back to the source.
5. If all metals conduct electricity with ease.
6. If we close the circuit when we switch off the electric light.
7. If we open the circuit when we switch on the electric light.
8. If conductance depends on the temperature of the wire.
58
6. Translate the following sentences paying special attention to the
words in bold.
1. The faster t he molecules of substance move, the higher is the tempera-
ture of the substance.
2. The large the water pipe, the more water passes through it.
3. The more you read, the more you learn.
4. The shorter the wire, the less is its resistance to current flow.
5. The greater the number of free electrons in a subs tance, the better that
substance conducts electricity.
7. Fill in the blanks with the following words and expressions: as, as
well, as well as.
1. It is necessary to remember the ter m “circuit” … it is almost impossible
to work with electricity without working with circuits.
2. Copper wires are mostly used … conductors of electricity.
3. A “short” may cause wire fault … cable fault.
4. In addition to travelling through solids, the electric current can flow
through liquids and gases … .
5. … a cold object and a hot one are brought into contact, the former gets
warmer and the latter gets colder.
6. … a conduct or becomes warmer , it is unable to pass electric char ges as
freely as it did before its temperature began to rise.
7. The magnitude of the current … the voltage and resistance may vary
from a minute amount to a very large quantity.
8. Fill in the blanks with suitable prepositions if necessary and make
up sentences with the following infinitives.
To answer … ; t o apply … ; to be interested … ; to con tribute … ; t o consist … ; to depend … ; to invite … ; to pay attention … ; to play a part … ; to
go … ; to be followed … .
9. Translate the following sentences.
1. Я не могу не ответить на этот вопрос.
2. Он не может не упомянуть об этом.
59
3. Мы не могли не вспомнить о пожаре, вызванном коротким замыка-
free – несвязанный электрон,
electromotive force (emf) |ɪˌlɛktrəˈməʊtɪv
excess|ɪkˈsɛs| – избыток, пре-
potential difference |pə(ʊ)ˈtɛnʃ(ə)l
deficiency|dɪˈfɪʃ(ə)nsi| – отсут-
provided |prəˈvʌɪdɪd| – при условии
manner|ˈmanə| – способ, метод,
to suspend |səˈspɛnd| – подвешивать
нием.
4. Она не может не думать о своей исследовательской работе.
5. Я не могу не знать, что короткое замыкание может вызвать повре-
ждение провода.
10. Speak on.
1. The properties of the electric circuit.
2. The conductors of electricity.
3. The insulators of electricity.
UNIT 11. POTENTIAL DIFFERENCE,
ELECTROMOTIVE FORCE AND RESISTANCE
Vocabulary
свободный электрон
вышение
ствие, нехватка
fɔːs| – электродвижущая сила
ˈdɪf(ə)r(ə)ns| – разница потенциалов
образ
The amount of electrons at a point is known as the potential at that point.
As was previously stated, there is always a disorderly movement of free electrons withi n al l sub stan ces, es peci al ly metal s. Th u s, i f at on e end o f a co nd uct or
there is an excess of electron s and at the ot her end – a deficiency, the excess of
electrons will flow in a disorderly manner towards th e point of defici ency. It is
the differen ce of potential that causes the free electrons to flow from one point
of the condu ctor to another . Of course, the gr eater the differen ce, the greater i s
the flow.
60