Basic Mathematics For Electricity And Electronics Answers

Федеральное агентство воздушного транспорта

Иркутский филиал

Федерального государственного бюджетного образовательного учреждения высшего образования

«Московский государственный технический университет

гражданской авиации» (МГТУ ГА)

Кафедра Гуманитарных и социально-политических дисциплин

( ГСПД )

Кузнецова Н . Б .

Principles of Electricity and Electronics

Учебное пособие по английскому языку

для обучающихся II курса специальностей 25.03.02 и 25.05.03

Иркутск 2019

Рецензент: к.фл.н., доцент Портнова Т.Ю.

Кузнецова Н.Б.

Principles of Electricity and Electronics: учебное пособие. – Иркутск: Иркутский филиал МГТУ ГА, 2019. – 102 с.

Учебное пособие составлено с учетом целей и задач программы по иностранному языку для специальностей 25.03.02 Техническая эксплуатация авиационных электросистем и пилотажно-навигационных комплексов и 25.05.03 Техническая эксплуатация транспортного радиооборудования.

Целью обучения является приобретение студентами коммуникативной компетенции, позволяющей использовать иностранный язык как в профессиональной деятельности, так и для целей самообразования.

Рассмотрено и одобрено на заседании кафедры гуманитарных и социально-политических дисциплин МГТУ ГА (ИФ) протокол № 7 от 19 марта 2019.

UNIT I ―THE NATURE OF ELECTRICITY
UNIT II ―ELECTRIC CURRENT AND ITS TYPES
UNIT III ―ELECTRIC POWER SYSTEMS
UNIT IV ―TRANSFORMERS
UNIT V ―RECTIFIERS AND AMPLIFIERS
READING COMPREHENSION

UNIT I "THE NATURE OF ELECTRICITY"

Vocabulary

Ex.1 Give the initial form of the following words:

followed, developed, electrons, produced, communications, locked, expanding, pouring, receivers, combined, enabled, applied, general, given, offers, leading, senses.

Ex.2 State to what parts of speech the following words belong:

discovery, investigation, physical, rapidly, directly, receiver, communication, decisive, shaping, computer, sensitivity, extension, structure, visible, optical, significant, industrial, treatment.

Form verbs adding the suffix -en to the given adjectives, translate them:

Example: fast — твердый, to fasten — затвердевать

bright, dark, sharp, wide, less, broad, deep, short, weak, hard.

Form verbs with an opposite meaning adding the prefix un-. Translate them into Russian:

Example: to cover — покрывать, to uncover — раскрывать

to close, to load, to tune, to tie, to fasten, to charge, to balance, to fix, to lock, to pack, to bend.

Ex.3 Read and translate the text:

It was known since the ancient Greeks that when a piece of amber or glass is rubbed with silk or fur, it achieves the power of attracting light objects. Later on, this was studied and the word ―electric (after Greek ―electron ―amber) was put in use. During 18-19 ^th centuries many discoveries about the nature of electricity were made: Charles Coulomb investigated the forces between the charged objects; Benjamin Franklin invented the lighting rod, etc.

There was developed an idea 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.

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 other certain substances due to which they store energy in a field 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 condensers plates. Rubbing glasses 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 the latter type of electricity.

Ex.4 Answer the following questions:

Under what conditions can amber or glass attract light objects?
What discoveries about the nature of electricity were made during the 18-19 ^th centuries?
What happens to the opposite kinds of electricity?
What happens to the similar kinds of electricity?
What classes can the study of electricity be divided into?
What is magnetism?
What helps the molecules of iron to store energy in a field?
What is electrostatics?
What are the examples of static electricity?
What is electrodynamics?

Ex.5 Fill in the gaps with the words given below:

a) ancient, b) electrostatics, c) discoveries, d) amber, e) investigated, f) motion, g) electrons, h) opposite, i) between, j) phenomenon, k) lighting, l) three

The study of electricity may be divided into _______ classes.
It was known since the ________ Greeks that when a piece of _______ or glass is rubbed …
Electrodynamics is the study of electricity in ____________ .
___________ is the study of electricity at rest, or static electricity.
They store energy in a field because of the arranged movement of ________ the in their atoms.
The __________ kinds of electricity attract one another.
Charles Coulomb _____________ the forces _____________ the charged objects.
This _____________ was studied and the word "electric" was put in use.
Benjamin Franklin invented the _______________ rod.
During 18-19 ^th centuries many ____________ about the nature of electricity were made.

Ex.6 Find the odd word:

magnetism – electrostatics – density – electrodynamics
electric – voltage – electron – amber
molecule – atom – proton – cell
ancient – electricity – word – energy
Franklin – Coulomb – Charles – Newton

Ex.7 Make up word-combinations and translate them:

Ex.8 Give the initial forms of the following words:

devices, pieces, allowed, known, became, depended, rectifying, crystals, valves, reaching, receivers, understood, substances, semiconductors, insulators, invented, replacing, advantages.

Ex.9 State to what parts of speech the words in bold type belong to:

1. A proton has a positive electrical charge . 2. Don't charge this battery. 3. The operating range of this device is broad. 4. The capacities of these stations range from 600 to 700 kilowatts. 5. The structure of the atom is like the structure of our solar system. 6. I like to watch TV evening programs. 7. The room houses electronic devices. 8. The houses of the research institute are nearly in the center of the city.

Ex.10 Translate the following compound nouns:

Airline, sunlight, airstream, radio signal, waveform, wavelength, spaceship, power plant, timetable, block-diagram, pipeline, lifetime, radio receptor, code word, radio wave.

Ex.11 Form verbs with an opposite meaning adding the prefix dis- and translate them:

Example: to approve — одобрять, to disapprove — не одобрять to cover, to appear, to place, to continue, to agree, to charge, to connect, to close, to arrange, to assemble, to mount, to join.

Ex.12 Make up sentences from the following words:

is, study, electricity, of, at, rest, or, static, electrostatics, the, electricity.
electricity, study, of, be, divided, into, the, three, classes, may.
idea, was, developed, kinds, an, that, there, are, there, two, of, electricity.
the, 18 -, centuries, about, many, 19 ^th , discoveries, nature, during, of, were, electricity, made.
the, lighting, Franklin, invented, rod, Benjamin.
opposite, happens, the, kinds, to, of, what, electricity?

Ex.13 Complete the sentences:

The electricity which flows through wires for light and power purposes is a good example of …
Opposite kinds of electricity attract …
Similar kinds of electricity …
It was known since the ancient Greeks that when a piece of amber or glass is rubbed with silk or fur, …
They store energy in a field because of the arranged movement of the electrons in …
Electrostatics is the study of electricity at rest, …
Benjamin Franklin invented the …

Ex.14 Read and translate the dialogue:

A: When was the first recorded observation on electricity made?

B: As much as I know it was made by the Greek philosopher Thales.

A: What did he state, I wonder?

B: He stated that a piece of amber rubbed with fur attracted light objects such as feather. Later on Galileo discovered the laws of the pendulum and accelerated bodies. It was the time when the study of magnetism and of electrical phenomena began.

A: How what is found that some substances could be electrified?

B: It is a well-known fact that having been rubbed many substances behave like amber does.

A: When was the modern concern of the nature of electricity completely revolutionized?

B: During the 19th century the idea of the nature of electricity was completely revolutionized. In the electrical system there is a nucleus containing positively charged particles. These particles are called protons. The nucleus is surrounded by lighter negatively charged units – electrons. So, the most essential component of matter is made up of electrically charged particles.

Ex.15 Complete the sentences:

The first recorded observation on electricity was made by ….
The most essential component of matter is made up of ….
A piece of amber rubbed with fur attracted light objects such ….
It is a well-known fact that having been rubbed many substances behave ….
During the 19th century the idea of the nature of electricity was ….
Galileo discovered the laws of the pendulum and ….

Vocabulary

force

cила

burst

вспышка

heating

отопление

businesses

промышленные предприятия

therefore

поэтому

artificially

искусственно

generating plant

генераторная станция

power station

электростанция

it's hard to overstate

трудно переоценить

10.

home appliances

10. бытовая техника

11.

to run processing equipment

11. для запуска технологического оборудования

12.

control systems

12. системы управления

13.

present-day jobs

13. современные рабочие места

14.

nonexistent

14. отсутствовать

15.

to live the way we're used to

15. жить так, как привыкли

16.

if you doubt that

16. если вы сомневаетесь в этом

17.

to occur

17. возникать/происходить

18.

to go out

18. погаснуть

19.

to shut down

19. прекратить работу

20.

air conditioning

20. кондиционирование воздуха

Ex.16 Give the initial words of the following derivatives:

Example: wireless — wire, transmission — to transmit

greatly, discharge, lecturer, atmospheric, successful, improvement, inventor, radiation, definition, equipment, purely, economic, powerful, development, operation, rapidly, information, atomic, magnetic, agreement, regulation, instruction, communication, technological, considerable, generation, separately, production, industrial, historic, logical, researcher.

Ex.17 State what parts of speech the underlined words belong to. Translate the sentences into Russian:

1. The study of this phenomenon is very important. The physicists study the structure of matter. 2. Energy can have many forms . What forms the basis of this compound? 3. We time our clock by radio. It is high time to go to the Institute. 4. The train leaves at six in the evening. Will you go to the Crimea on leave ? 5. We must set the time for the beginning of the experiment. Give this worker a set of tools. 6 . Air is a mixture of gases. Air the room, please. 7. The generator charges the batteries. The charges of an electron and of a proton are equal in strength. 8. The experiment may result in a new scientific concept. The result of the process was the release of the energy. 9. Point out a mistake in this translation. Speak to the point . 10. It is light in the room. Don't light the lamps.

Ex.18 Read and translate the text

What is Electricity?

Electricity is a natural force produced by the movement of electrons. The most common natural source of electrical energy is lightning. Of course, the energy produced by a burst of lightning is much too strong to be used in homes and businesses.

Therefore, the electrical energy we use every day is produced artificially in generating plants and power stations. It's hard to overstate the importance of electricity to today's homes and industries. Electrical power is used for lighting, heating, air conditioning, and running home appliances.

Manufacturing plants use electricity to run processing equipment, control systems, and computers. Millions of present-day jobs would be radically different or nonexistent without electricity. We couldn't live the way we're used to without electricity. If you doubt that, think about the panic that occurs when your lights go out or when your bank's computer shuts down!

Ex.19 Match definitions with the words

1. a flexible metallic conductor, especially one made of copper, usually insulated, and used to carry electric current in a circuit

a circuit

2. the round or oval shape formed by a line, string, etc, that curves around to cross itself

a particle

3. special capability or power

magnetism

4. an extremely small piece; tiny fragment:

electricity

5. a complete or partial path over which current may flow

a compass

6. the force exerted by a magnetic

field

wire

7. any phenomenon associated with

stationary or moving electrons, ions, or other charged particles

a loop

8. a device with magnetic needles used for showing the direction one is facing

property

Ex.20 Read and translate the text

The History of Electricity

Humans have experienced the effects of electricity since ancient times. Early men and women observed the effects of lightning, magnetism, and static electricity without understanding where these forces came from or what caused them.

The first experiments with electricity were performed about 600 B.C. in ancient Greece. The Greeks noted that when the mineral amber was rubbed against fur, the amber gained the ability to attract small objects. Today, we understand that this attraction is caused by static electricity. However, in ancient Greece, there was no real understanding of this phenomenon and no practical application for it.

By the fifteenth century, scientists began to examine natural forces more closely and developed theories about them. Over the next several hundred years, scientists such as Alessandro Volta, George Ohm, James Joule, and James Watt made important discoveries about electricity, magnetism, and physics. All of these men gave their names to electrical properties and units (volt, ohm, joule, watt).

In America, an important advance in electrical studies was made in 1752 when Benjamin Franklin performed his famous experiments with lightning and kites. Franklin attached a metal key to a kite string and sent the kite sailing into a lightning storm. He then observed the discharge of lightning firsthand as it struck the key. Franklin observed that the lightning was an intense electrical discharge between the negatively charged lower portion of thunderclouds and the positively charged earth. His observations provided important insights into the nature of electricity.

The nineteenth century saw the practical application of electrical principles to commercial products and devices. The first truly successful application of electricity was made in 1837 with the telegraph. The telephone was invented in 1876 by Alexander Graham Bell; then came the incandescent light, invented by Thomas Edison in 1878 (Figure 1). In their day, these devices revolutionized the world, and all are still indispensable in our world today.

Ex.21 Fill in the table with the names and English equivalents:

	заметили, that янтарь, потертый против меха gained the способность to attract мелкие предметы
Scientists of the 15 ^th century	начали исследовать natural forces more closely and развивать теории about them
	обеспечил important insights into the природу электричества
	изобрел the radio
	invented the лампу накаливания
	made важные открытия about electricity, magnetism, and physics

Ex.22 Change the Voice in sentences from the table (from Active Past into Passive Past)

V-ed (V2) – was/were V-ed (V3) Example:

(Active) The scientists of the 15 ^th century began to examine natural forces more closely and developed theories about them.

(Passive) Natural forces were examined more closely and theories about them were developed by the scientists of the 15 ^th century.

Ex.23 Translate the sentences into Russian. Pay attention to the verbs in the Simple Passive:

1. Sounds are produced by the vibration of matter. 2. Waves are carried in all directions from the vibrating body. 3. The first-year students are not taught special subjects. 4. Many problems of great interest are discussed at our seminars. 5. We were invited to the conference 6. The methods of radio engineering are now applied in various fields of science and technology.7.The agreement was signed ten years ago 8.The research will be carried out over a period of four months, 9. Much attention is given to the development of radio engineering. 10. Lasers are used for many scientific, medical and industrial purposes. 11. The laboratories of our University are equipped with modern devices. 12. The results of these experiments will be published in a scientific journal. 13. The importance of sport is known to everybody. 14. We were provided with the necessary literature. 15. The young scientist was invited to take part in the conference.

Ex.24 Say the following sentences in the Simple Passive. Use the words in bold as the subjects of your sentences:

Example:

Scientists use crystals in electronic devices.

Crystals are used by scientists in electronic devices.

The scientists developed several types of lasers . 2. I will inform you about the new discovery . 3. Solar batteries generate electricity . 4. The researcher carries out the experiments at high temperatures. 5. You always make the same mistakes . 6. He will bring the book next time. 7. Radio employs electrical energy to transmit sounds, images and signals. 8. The lecturer spoke about the latest works in the sphere of radio electronics. 9. He showed me the articles from the latest magazine. 10. Mendeleyev presented his table in 1869. 11. New data will support the results of our research. 12. These devices distribute the electric energy . 13. Heat converts ice into water. 14. A.S. Popov invented the first radio receiver . 15. The engineer will check the apparatus in the lab. 16. Their laboratory occupies a separate part of the building . 17. Radio devices perform various communication tasks . 18. We use such devices for amplification of radio signals.

Ex.25 Read the dialogues and find the English equivalents:

наблюдений

7.на самом деле, в действительности

8.насколько мне известно

9.положительно заряженные частицы

10.перья и соломинки

11.законы маятника и ускоренных тел

12.проходить/истекать

13.позднее было обнаружено

14.общеизвестный факт

15.разнородные вещества

16. наиболее существенная составная часть вещества

17. кулон

18.единица измерения

19. приобретать электрические заряды

20. за секунду времени

Dialogue 1

When was the first recorded observation about electricity made?
As far as I know it was made by the Greek philosopher Thales. - What did he state, I wonder?
Don't you know? He stated that a piece of amber rubbed with fur attracted light objects such as feathers and bits of straw.
Did he make any experiments?
No, as far as it is known Thales liked to speculate but he did not experiment systematically. Twenty two centuries elapsed before there was any progress.
Oh, it was just about the time that Galileo discovered the laws of the pendulum and accelerated bodies. So it was at the time when the study of magnetism and of electrical phenomena began.

Dialogue 2

How was it found out that some substances can be ―electrified?
It is a well-known fact that having been rubbed many substances behaved like amber did.
Can only similar substances become electrified or acquire electrical charges, being touched together and then separated?
No. Later on, it was discovered that any of two dissimilar substances could be electrified. As a matter of fact rubbing is not essential. It merely forces the two substances into close contact.

Dialogue 3

What do you know about the nucleus, the proton and the electron?
In the electrical system there is a nucleus containing positively charged particles. These particles are called protons. The nucleus is surrounded by lighter negatively charged units – electrons. So, the most essential constituent of matter is made up of electrically charged particles.
When matter is neutral?
Everybody knows that matter having equal amounts of both charges is neutral - that it produces no electrical effects.
And what happens if the number of negative charges is unlike the number of positive ones?
Well, then the matter will produce electrical effects. Having lost some of its electrons, the atom has a positive charge; having an excess of electrons – it has a negative charge.
So, as a matter of fact you do know the material.

Dialogue 4

When will electrons move?
If given a path, electrons dislodged from the parent atom, will move.
Well, what do you know about the electric current?
The electric current is a quantity of electrons flowing in a circuit per second of time.
And what is the unit of measure for current?
The unit of measure for current is the ampere. One coulomb passing a point in a circuit per second, the current strength is 1 ampere. The ampere is therefore a rate unit.

Ex.26 Define the tense-forms of the verbs in the following sentences. Translate the sentences into Russian:

1. The engineers were attaching the wires to the devices when I came in. 2. At present they are studying various aspects of this problem. 3. When we listen to a radio we are using the rays that are called radio waves. 4. The scientist was solving a new problem when we visited his laboratory last week. 5. What is she doing this week? 6. John was reading a book when I came to see him. 7. My friend is writing an article for the newspaper. 8. The student was carrying out this experiment for twenty minutes. 9. I'm working too hard this year. 10. Molecules in a gas are constantly moving. 11. The electron is circling in an orbit around a nucleus.

Ex.27 Read the following sentences and say which of them are in the Active and which are in the Passive Voice. Translate them into Russian:

1. While the experiment was being carried out nobody left the laboratory. 2. A new type of computing equipment is being produced at our plant. 3. At present scientific work is being done mostly by large groups of researchers. 4. The apparatus will be working when you come. 5. The scientists who are carrying out research into nuclear physics deal with the most difficult problems. 6. For twenty minutes the air in the laboratory was being purified by two ventilators. 7. The solar battery is converting the energy of sun rays directly into electric energy. 8. This experiment was being carried out under low pressure. 9. For a long time the electronic devices were being used for control. 10. An interesting research in the field of electronics is being done at our Institute. 11. Prospects of the usage of solar energy are already understood by everybody. 12. Now solar energy is being studied by a lot of research groups. 13. We were looking for a more simple method of solution but could not find it. 14. The engineers will discuss the advantages of this new system. 15. Our laboratory is housed in an old building.

UNIT II "ELECTRIC CURRENT AND ITS TYPES"

Vocabulary

Ex.1 Form adjectives adding the suffix -ful to the given nouns. Translate the nouns and adjectives into Russian:

Example : beauty — beautiful — красота — прекрасный harm, power, use, fruit, skill, purpose, wonder, care, success, truth, hope, taste, respect, meaning, art, change, peace, watch, help.

Ex.2 Form adjectives adding the suffix -less to the given nouns. Translate the nouns and adjectives into Russian:

Example : hope — hopeless — надежда — безнадежный

wire, noise, help, motion, friend, aim, shape, branch, cause, character, sense, respect, object, ground, harm, change, power, colour, limit, meaning, voice, weight, life.

Ex.3 Read the words and say what suffixes they have and what parts of speech they belong to:

use, useful, usefulness; invent, inventor, invention; transmit, transmitter, transmission; work, worker; special, speciality, specialist; practice, practical; contain, container; lecture, lecturer; create, creative, creation; accelerate, acceleration, accelerator; determine, determination; proper, properly, property; science, scientific, scientist; discover, discovery, discoverer; important, importance; react, reaction, reactor, reactivity; arrange, arrangement; capable, capability; apply, application.

Ex.4 Read and translate the text

Electric Current

Electric current is traditionally defined as the ordered flow of electrons in a conductor. As conductors we can use all metals. Metals are good conductors because they have free electrons. The best conductors are such metals as silver, gold, copper, and aluminum.

There are two types of electric current. The first type is called direct current (DC), the second type is called alternating current (AC). Direct current is the current which always flows in one direction. There are two directions of DC flow. One direction is from positive potential to negative potential, and it is called technical direction of DC flow. The second direction is from negative potential to positive potential and it is called scientific direction of DC. Negative potential corresponds to excess of electrons; positive potential corresponds to their deficit. The technical direction of DC flow appeared when people started using DC for practical applications without knowing anything about electrons.

Alternating current is the current which changes its direction many times per second. The number of changes of direction per second is called frequency of AC. Frequency of AC in the mains in Russia is 50 cycles per second, voltage, is 220 volts. Frequency of AC in the mains in the USA is 60 cycles per second. Frequencies of AC are different because there is a design rule, which reads: "The higher is the frequency of AC the smaller and lighter are all power transformers on board".

Electric current is measured in amperes. One ampere is defined as one coulomb per second. One coulomb of electricity is the amount of electrons, which, flowing through a solution of nitrate of silver, deposits 1.118 milligrams of silver on the electrode. Practically used units for measuring electric current are milliamperes and microamperes. Frequency of AC in the mains on board of aircraft is 400 cycles per second, voltage is 117 volts.

The satisfactory performance of any modern aircraft depends to a very great degree on the continuing reliability of electrical systems and subsystems. Improperly or carelessly installed or maintained wiring can be a source of both immediate and potential danger. The continued proper performance of electrical systems depends on the knowledge and technique of the mechanic who installs, inspects, and maintains the electrical system wires and cables.

Ex.5 Answer the questions:

1. What is electric current? 2. What substances can be used as conductors? 3. Why all metals are good conductors? 4. Which metals arc the best conductors? 5. What types of electric current do you know? 6. What is direct current? 7. How many directions of direct current flow do we know? 8. In what direction does direct current actually flow? 9. What is the meaning of positive potential? 10. What is the meaning of negative potential? 11. What is alternating current? 12. What is frequency of alternating current? 13. What is frequency of AC in the mains in Russia? 14. What is frequency of AC in the mains in the USA? 15. What is frequency of AC in the mains on board of Civil Aviation airplanes? 16. Why frequencies of AC are different? 17. What units are used for measuring electric current? 18. How do we define one ampere? 19. What values do we measure in coulombs? 20. What is one coulomb of electricity? 21. What units for measuring electric current are used practically? 22. Why is it necessary to provide a proper operation of onboard electrical systems and subsystems? 23.What should mechanics have to ensure the continued proper performance of electrical systems?

Ex.6 Put the following words into the text:

a) conductors b) copper c) electrons d) insulators e) metals f) negative g) plug

h) positive i) safety j) touch k) travel

Electricity is created when _____________________ move between atoms. ______________ atoms look for free _________________ electrons and attract them. __________________ are used as materials that let electrons _____________ freely. Good materials are _______________ and other _______________. ________________ are materials that are important for our ______________ . Without them we couldn't ________________ a hot pan or _______________ in a toaster.

Ex.7 Define the tense-forms of the verbs in the following sentences. Translate them into Russian:

1. I have just turned the radio on. 2. Have you listened to the news? 3. He understood the text after he had read it again. 4. I have read this book three times. 5. He has never been to Great Britain. 6. He has seen this film/ 7. Have you ever been to London? 8. He had finished his work by 5 o'clock yesterday. 9. The technician will have recorded the data before you come. 10. I have not seen him since he graduated from the University. 11. We will have completed our experiments by the end of the week. 12. My friend had prepared his report before we spoke to you. 13. Electronics has made a rapid progress. 14. He had published his article by the end of the month. 15. We've played lots of matches this season, but we haven't won many. 16. She has spent a great deal оf time in the USA. 17 . They'll have finished their work by lunchtime. 18. Have you read anything interesting lately? 19. They've probably forgotten the time. 20. They have accepted the scientist's suggestion. 21. Moscow Radio has been transmitting its programs to other countries since the thirties. 22. We had been conducting this experiment for two hours before you came. 23. When she arrived, I had been waiting for two and a half hours. 24. It has been raining since two o'clock.

Ex.8 Translate the following sentences into Russian paying attention to the predicates in the Perfect Passive:

1. This theory has been used for analyzing the experimental data. 2. In my opinion this result has not been proved by anybody. 3. The apparatus used in our research has been described recently. 4. We must compare our data with those that have been obtained by other investigators. 5. Many difficulties had been overcome before the researcher succeeded in his work. 6. After the new device had been tested it was installed in our laboratory. 7. The construction of this television center will have been completed by the end of the next year. 8. In our country great progress has been achieved in developing all branches of science and engineering. 9. Many different devices have been created in order to improve the performance of communications. 10. The information has been based on the data received from a computer. 11. Much research has been carried out in order to establish the causes of this phenomenon. 12. This question has already been discussed at the conference. 13. By the end of the year a large variety of semiconductor devices will have been produced. 14. This equipment had been repaired before you came. 15. This text has just been translated. 16. Mendeleyev's periodic law has been accepted as a universal law of nature.

Ex.9 Compare the use of the Past Simple and the Present Perfect in the following sentences, translate them into Russian:

I have written several letters today. I wrote several letters yesterday. 2. They have made a new experiment this week. They made a new experiment last week. 3. She has been to the theatre this month. She went to the theatre last month. 4. Have you ever been to London? Yes, I've been there once. I went there in 2011. 5. Have you ever seen "Hamlet"? Yes, I've seen "Hamlet" several times. I saw it at our theatre three years ago and at Moscow theatres in 2012 and 2015. 6. He has graduated from the Moscow University. He graduated from the Moscow University in 2008. 7. He has seen this film. He saw this film yesterday. 8. He has improved his device; you may use it. He improved his device a week ago. 9. He prepared his report ahead of time. Have you prepared your report? 10. The results of this research were published long ago. My friend has already published the results of his discovery.

Ex.10 Read and translate the text

Types of Current

If two equally and oppositely charged bodies are connected by a metallic conductor such as a wire, the charges neutralize each other. This neutralization is accomplished by means of a flow of electrons through the conductor from the negatively charged body to the positively charged one. (In some branches of electrical engineering, electric current has been conventionally assumed to flow in the opposite direction, that is, from positive to negative.) In any continuous system of conductors, electrons will flow from the point of lowest potential to the point of highest potential. A system of this kind is called an electric current. The current flowing in a circuit is described as direct current (DC) if it flows continuously in one direction, and as alternating current (AC) if it flows alternately in either direction.

Three interdependent quantities determine the flow of direct currents. The first is the potential difference in the circuit, which is sometimes called the electromotive force (emf) or voltage. The second is the rate of current flow. This quantity is usually given in terms of the ampere, which corresponds to a flow of great amount of electrons per sec past any point of the circuit. The third quantity is the resistance of the circuit. Under ordinary conditions all substances, conductors as well as nonconductors, offer some opposition to the flow of an electric current, and this resistance necessarily limits the current.

The unit used for expressing the quantity of resistance is the ohm, which is defined as the amount of resistance that will limit the flow of current to 1 amp, in a circuit with a potential difference of 1 V. This relationship is known as Ohm's law and is named after the German physicist George Simon Ohm, who discovered the law in 1827. Ohm's law may be stated in the form of the algebraic equation E = I x R, in which E is the electromotive force in volts, I is the current in amperes, and R is the resistance in ohms. From this equation any of the three quantities for a given circuit can be calculated if the other two quantities are known. Another formulation of Ohm's law is I = E/R.

When electric current flows through a wire, two important effects can be observed: the temperature of the wire is raised, and a magnet or a compass needle placed near the wire will be deflected, tending to point in a direction perpendicular to the wire. As the current flows, the electrons making up the current collide with the atoms of the conductor and give up energy, which appears in the form of heat. The amount of energy expended in an electric circuit is expressed in terms of the joule.

Ex.11 Answer the questions:

Do the charges neutralize each other if two equally and oppositely charged bodies are connected by a metallic conductor?
Is this neutralization accomplished by means of a flow of electrons or by any other mean?
In which direction electrons will flow in any continuous system of conductors?
How do we call the current if it flows continuously in one direction?
How do we call the current if it flows alternately in either direction?
What is called as the electromotive force (emf) or voltage?
What quantity is usually given in terms of the ampere?
How do we call the unit used for expressing the quantity of resistance?
What relationship is known as Ohm's law?
What can be observed when an electric current flows through a wire?
In what unit of measurement the amount of energy expended in an electric circuit is expressed?

Ex.12 Read the text Types of Current and find the English equivalents:

Противоположно заряженный; металлический проводник; заряд; поток электронов; проводник; электротехника; непрерывная система; низший потенциал; высший потенциал; электрический ток; ампер; соответствовать; сопротивление; обычные условия; закон Ома; уравнение; формулировка; температура проволоки; атомы; измерять.

Ex.13 Make interrogative and negative forms of the following sentences:

Two equally and oppositely charged bodies are connected by a metallic conductor.
The charges neutralize each other.
Electrons flow through the conductor from the negatively charged body to the positively charged one.
Electrons flow from the point of lowest potential to the point of highest potential.
The current flowing continuously in a circuit in one direction is described as direct current?
Potential difference in the circuit is called the electromotive force or voltage.
The second is the rate of current flow.
The temperature of the wire is raised.
The electrons making up the current collide with the atoms.
The amount of energy expended in an electric circuit is expressed in terms of the joule.

Ex.14 Make sentences using these words and word combinations:

Metallic conductor; connected; neutralize; charged; bodies.
Electrical; engineering; current; electrical; opposite; positive; negative.
Flow; second; rate; current.
Limits; resistance; current; necessarily.
Law; can be stated; equation; Ohm's.
Collide; atoms; electrons; conductor; energy.
Joule; energy; amount; expended; circuit; electric.
Needle; compass; placed; deflected; magnet.

Ex.15 Translate into English:

Равные и противоположно заряженные тела соединены между собой металлическим проводником.
Поток электронов от отрицательно заряженного тела к положительно заряженному телу.
Поток электронов от точки с низшим потенциалом к точке с высшим потенциалом.
Сопротивление в сети ограничивает величину тока.
Закон Ома можно выразить в виде следующего алгебраического уравнения.
При прохождении электрического тока по проводу, температура провода повышается.
При столкновении электронов тока с атомами проводника образуется энергия.
Стрелка компаса, расположенного рядом с проводом, будет отклоняться в направлении, перпендикулярном проводу.

Ex.16 Read and translate:

Aviation Talk

Instructor: Presently we are starting to understand general principles of operation of on-board, or flight, computers. Our first topic in this series is called "Electric Current".

Student A: I understand that all power supply units of computers require alternating current for their operation. As we all know, to alternate means to change.

Instructor: By definition, alternating current is the current that changes its direction of flow many times per second.

Student B: But what does alternating current have to do with computers?

Instructor: All computers take their power from the mains. And in the mains we have alternating current which must be converted into direct current, used by all computers.

Student A: Why do we always and everywhere have alternating current in the mains?

Instructor: AC is so popular because of its very important advantage - transform ability.

Student B: And what does it mean?

Instructor: It means that we can change its voltage according to our needs by using stepping-up or stepping-down transformers.

Student B: But AC has another parameter, which can be changed - frequency.

Student A: I've never heard anything about changing frequency of AC. Up to now, at least.

Instructor: We do not change frequency; we choose it from the very beginning.

Student B: We've already heard that the higher is the frequency in the mains the smaller and lighter are all power transformers. Why not to have in our mains alternating current of a higher frequency?

Student A: Yes, why not to have in our mains 400 cycles per second AC, as in aviation? Our home TV sets would be twice as light.

Instructor: We must not forget about radiation losses involved. The higher is the frequency in the mains, the higher are radiation losses in transmission lines. And distances in our country are really great .The present value of 50 cycles per second is optimum.

Student B: How do we measure AC?

Instructor: Current is measured by connecting the meter in series. That means that we have to disrupt the circuit first, then we have to connect the meter so that all current would flow through the meter.

Student B: And in what units do we measure current?

Instructor: Current is measured in amperes, milliamperes, or microamperes, depending on strength of the current.

Student A: What kind of meters do we use for measuring current?

Instructor: For measuring current we use meters with very low inner resistance.

Student B: Sometimes we have to measure voltage. What kind of meters do we use in this case?

Instructor: For measuring voltage we use meters with very high inner resistance. And we must not forget what in this case we connect the meter in parallel.

Student A: We both thank you for answering our questions.

Ex.17 Give the initial words of the following derivatives:

primarily, considerable, selective, comparison, investment, separately, mobility, industrial, invention, development, actively, transformation, logical, clearly, communication, transmission, original, digital, researcher, information.

Ex.18 Form adverbs adding the suffix -ly to the given adjectives and translate them: Example: sure – surely

separate, objective, quick, primary, active, considerable, complete, evident, social, competitive, mechanical, great, general, definite, absolute, different, automatic, sure, easy, similar, certain, frequent, constant, direct, main, probable.

Ex.19 Form adjectives adding the prefix -un to the adjectives and translate them:

Example: natural – unnatural

important, usual, complicated, completed, conventional, human, interesting, stable, economic, able, reliable, happy, available, limited, productive, balanced, like, easy, fortunate, original, satisfactory, sophisticated, true, natural, disciplined, discovered.

Ex.20 Read the words and say what parts of speech they belong to:

produce, product, production; frequent, frequency; physics, physical, physicist; act, active, activity; develop, development; nature, natural; measure, measuring, measurement; direct, director, directive, direction, directness; operate, operating, operation, operative, operator; relative, relatively, relation, relativity; mean, meaning, means; technical, technique, technician; system, systematical, systematically; electron, electronic, electronics; consider, consideration, considerable, considerably.

Ex.21 Read and translate the text:

Electrical safety

It is important to understand why and how you can protect yourself from electrical injuries. Electric shock occurs when an electric current passes through your body. It can lead to heart failure and can damage other parts of your body. It can also burn your skin and other body tissues.

A very weak electrical object, like a battery cannot do any harm to you, but inside the house you have devices and machines that use 220 volts. Most machines in your house have safety features to protect you. It something goes wrong, a special wire leads the electricity to the ground where nothing can happen.

There are also electrical dangers outside your house. Trees that touch power lines can be dangerous. Lightning has more than enough electricity to kill a person. If you get caught in a thunderstorm stay away from open fields and high places.

One of the safest places is your car, because lightning will only hit the outside metal of the car.

Ex.22 Match the words with their meanings:

i. a powerful flash of light in the sky,

during a thunderstorm

10. current

j. a large wire that carries electricity

above or under the ground

11. power line

k. happen

12. tissue

l. things in machines or electric objects that protect you from being hurt

13. heart failure

m. the material that forms animal or plant cells

UNIT III "ELECTRIC POWER SYSTEMS"

Ex.1 Match English and Russian equivalents:

Ex.2 Read and translate the text.

Electric Power Systems

The production and transmission of energy in the form of electricity have important economic advantages in terms of cost per unit of power delivered. Electric power systems also make possible the utilization of hydroelectric power at a distance from the source. Alternating current is generally used in modern power systems, because it may be easily converted to higher or lower voltages by means of transformers. Thus, each stage of the system can be operated at an appropriate voltage. Such an electric power system consists of six main elements: the power station; a set of transformers to raise the generated power to the high voltages used on the transmission lines; the transmission lines; the substations at which the power is stepped down to the voltage on the sub transmission lines; the sub transmission lines; and the transformers that lower the sub transmission voltage to the level used by the consumer's equipment.

In a typical system the generators at the central station deliver a voltage of from 1000 to 26,000 volts; higher voltages are undesirable because of difficulties of insulation and the danger of electrical breakdown and damage. This voltage is stepped up by means of transformers to values ranging from 138,000 to 765,000 V for the primary transmission line. At the substation the voltage may be transformed down to levels of 69,000 to 138,000 V for further transfer on the sub transmission system. Transformers step down the voltage again to a distribution level. Finally the voltage is transformed once again at the distribution transformer near the point of use to 240 or 120 V.

The central station of a power system consists of a prime mover, such as a water or steam turbine, which operates an electric generator. Most of the world's electric power in the early 1990s was generated in steam plants driven by coal, oil, nuclear energy, or gas, with lesser percentages generated by hydroelectric, diesel, and internal-combustion plants.

The lines of high-voltage transmission systems are usually composed of wires of copper, aluminum, which are suspended from tall latticework towers of steel by strings of porcelain insulators. By the use of clad steel wires and high towers, the distance between towers can be increased, and the cost of the transmission line thus reduced. In modern installations with essentially straight paths, high-voltage lines may be built with as few as eight towers to the kilometer. In some areas high-voltage lines are suspended from tall wooden poles spaced more closely together. For lower voltage sub transmission and distribution lines, wooden poles are generally used rather than steel towers. In cities and other areas where open lines create a hazard, insulated underground cables are used for distribution. Any electric-distribution system involves a large amount of supplementary equipment for the protection of generators, transformers, and the transmission lines themselves. The system often includes devices designed to regulate the voltage delivered to consumers and to correct the power factor of the system.

Ex.3 Answer the questions:

Can we state that the production and transmission of energy in the form of electricity is an important economic advantage?
Do electric power systems make possible the utilization of power at a distance from the source?
Why alternating current is generally used in modern power systems?
By means of what equipment the current is easily converted to higher or lower voltages?
Does an electric power system consist of six main elements? Name them.
Are transformers used to raise the generated power to the high voltages used on the transmission lines?
What does the central station of a power system consist of?
Why do we call a water or steam turbine as a prime mover?
Was most of the world's electric power in the early 1990s generated in steam plants?
What are the lines of high-voltage transmission system usually composed of?
How can the distance between towers be increased?
What are generally used for lower voltage sub transmission and distribution lines?
In cities and other areas where open lines create a hazard, insulated underground cables are used for distribution.
Where and why insulated underground cables are used for distribution?
How can you explain the fact that any electric-distribution system involves a large amount of supplementary equipment?
Does the system include devices designed to regulate the voltage?
What kind of equipment is used for protection of generators, transformers, and the transmission lines?
What do electric power systems include?

Ex.4 Find in the text Electric Power Systems English equivalents and write them down:

Производство и передача электроэнергии; стоимость; единица энергии; источник; современные энергетические системы; трансформатор; шесть основных элементов; электрическая станция; передающие линии; подстанция; понижать; повышать; оборудование потребителя; поломка; уровень распределения; электрический генератор; медные провода; алюминий; керамические изоляторы; деревянные столбы; регулировать напряжение; коэффициент мощности.

Ex.5 Make interrogative and negative forms of the following sentences:

Transmissions of energy in the form of electricity have important economic advantages.
Electric power systems make possible the utilization of power at a distance from the source.
Alternating current is generally used in modern power systems.
Each stage of the system can be operated at an appropriate voltage.
An electric power system consists of six main elements.
Transformers are used to raise the generated power to the high voltages used on the transmission lines.
Transformers are used to lower the transmission voltage to the level used by the consumer's equipment.
The central station of a power system consists of a prime mover.
High-voltage transmission systems are usually composed of wires of copper.
Any electric-distribution system involves a large amount of supplementary equipment.
System includes device to regulate the voltage delivered to consumers.
Underground cables are used for distribution in cities.

Ex.6 Make sentences using these words and word combinations:

Power; electric; distance; systems; power; source.
Elements; six; consist; main; power; system.
Transformers; used; to rise; high; voltage; power; generated.
Step down; consumers; transformers; deliver; power.
Prime mover; central; station; consist of.
Used; high voltage; lines; transmission; wires; towers of steel; insulators; porcelain.
Used; insulated; cables; underground; cities.
System; protection; generators; transformers; equipment; supplementary.

Ex.7 Translate into English:

Передача электрической энергии через высоковольтные линии.
Электрическая станция является основным элементом энергосистемы.
Энергия повышается и понижается при помощи трансформаторов.
На электрических подстанциях напряжение понижается до уровня потребителя.
Большинство энергии в мире генерируется на тепловых станциях.
Тепловые станции используют в качестве топлива уголь, газ, мазут и ядерное топливо.
Высоковольтные линии электропередачи состоят из мачт, проводов и керамических изоляторов.
В городах применяются подземные кабеля для передачи электроэнергии.
Для защиты трансформаторов и генераторов используется большое количество вспомогательного оборудования.

Ex.8 Give the initial forms of the following words:

scientists, invented, calculating, devices, developed, formulating, advances, introduced, units, stores, computing, shaped, circuits, names, capacities, devised, machines, designing.

Ex.9 Give the initial words of the following derivatives:

invention, development, mechanical, notable, digital, symbolically, faster, production, electronic, researcher, earlier, storage, magnetic, densely, equipment.

Ex.10 Form verbs adding the prefixes a) de- and b) re- to the given verbs and translate them:

Example: a) to code - кодировать, to decode - декодировать; b) to color - красить, to recolor - перекрашивать

to compose, to couple, to generate, to activate, to tune, to magnetize, to polarize, to energize, to excite, to clutch, to camp, to carbonize, to frost, to control, to mount, to form;
to arm, to arrange, to consider, to count, to cover, to model, to construct, to name, to equip, to build, to make, to move, to organize, to place, to produce, to distribute, to measure, to create, to use.

Ex.11 Translate the following sentences into Russian paying attention to the degrees of comparison:

1. This classroom is larger and lighter than other classrooms. It is the largest and the lightest room here. 2. Mathematics is more important for technical students than many other subjects 3. Lesson 3 is much easier than lesson 4. 4. This article is much more interesting than that one. 5. Exercise 10 is the most difficult one. 6.This instrument is more efficient than the other one. 7. This town is as large as that one. 8. These engines are not so powerful as those motors. 9. The speed of our first sputniks was as big as 11 kilometers per second.
1. The nearer the earth, the denser the atmosphere. 2. The higher the voltage, the higher is the electron velocity. 3. The bigger the mass, the bigger the weight of the body. 4. The higher the temperature, the more rapid is the motion of the molecules. 5. The greater the number of free electrons in a substance, the better this substance conducts electricity.

Ex.12 Translate the following sentences paying attention to the Participle II:

1. The discovery mentioned remained unknown to most scientists for a long time. 2. The equipment tested required further improvement. 3. When passed through a motor, electric current can do work. 4. The students have conducted all the experiments. 5. These instruments recorded the cosmic rays and the information obtained was sent back by the radar to the ground. 6. When heated, a magnet loses some of its magnetism. 7 The results received changed with material used. 8. Unless repaired, this part cannot be used in the radio set. 9. The substances investigated showed quite interesting properties. 10. When developed, the device was used for amplification of radio signals. 11. The developed technology enables us to improve the quality of articles produced. 12. The first laser was developed in 1960. 13. The methods introduced received general recognition. 14. If frozen, water becomes ice. 15. The device used in our work is up-to-date. 16. The apparatus tested is looked upon as an experimental one. 17. When required, these data will be applied in our practical work. 18. The investigation analyzed resulted in an interesting discovery.

Ex.13 Match the words which are opposite in meaning:

a) fast, expensive, early, high, tremendous;

b) low, late, tiny, cheap, slow.

Ex.14 Read and translate the text

Electromagnetism

Electricity and magnetism combine to form one of the fundamental forces of the universe – electromagnetism. The two constantly interact, and the relationship between them is one of the most important in physics. For example, an electric current passing through a wire creates a magnetic field; and if the lines of force around a magnet are cut by a passing object, an electric current will be produced.

Magnets are attracted to iron and to any material that contains iron. Magnets have two poles, a north pole and a south pole. Unmagnetized iron and steel have magnetic regions of atoms called domains that are jumbled up and point in lots of different directions. When iron or steel becomes magnetized, the domains become aligned and they all point in the same direction. One end of each domain points toward the magnetic north pole.

Electronics is a new branch of physics, and one that plays an increasingly important part in our lives. It is concerned with the use of electricity to produce signals that carry information and control devices such as computers. These devices contain electric circuits through which electric current flows. The controlling parts in a circuit are called components, and these include diodes and transistors. Components can amplify currents, switch them on and off, or change their direction.

Ex.15 Match the Russian and the English equivalents:

a. часть

2. amplify

b. выключать

3. interact

c. устройство

4. jumble up

d. создавать

5. cut

e. течь

6. point

f. пересекать

7. align

g. двигаться в беспорядке

8. universe

h. область; регион

9. create

i. расширять; усиливать

10. contain

j. содержать

11. device

k. выравниваться

12. switch off

l. указывать

13. region

m. домен

14. direction

n. область; сфера

15. field

o. вселенная

16. be concerned

p. отрасль

17. part

q. взаимодействовать

18. branch

r. немагнитный

19. flow

s. заниматься

20. unmagnetized

t. направление

Ex.16 Complete the sentences:

The relationship between electricity and magnetism is called…….
Magnets are attracted to…..
Magnets have two…..
Domains are……
Domains become aligned and point to the same direction when….
Electronics is concerned with…..
Electric current in electronic devices flows through……
Components of controlling parts in electronic devices can……

Ex.17 Answer the questions:

What is electromagnetism a combination of?
How can be electric current produced with the help of magnetism?
How do atoms behave in unmagnetized iron and steel?
Where can be electronics applied?
What are diodes and transistors for in electronic devices?

Ex.18 Fill in the table with the corresponding nouns, adjectives, verbs and adverbs where possible

UNIT IV "TRANSFORMERS"

Vocabulary

мощность

24.

transformation ratio

24. коэффициент трансформации

25.

under conditions

25. в условиях; при работе, в режиме

26.

26. нагрузка; под нагрузкой

27.

overheating

27. перегрев

28.

ultimate

28. завершающий, конечный

29.

failure

29. отказ, авария

30.

encapsulated

30. герметизированный

31.

to explode

31. взрываться

32.

lossless

32. без потерь

33.

product is equal

33. произведение равно

34.

common source

34. обычная, распространенная причина

35.

low-quality

35. низкокачественный

36.

device

36. устройство

Ex.1 Read and translate the text

Transformers

A transformer consists of two insulated coils of wire linked with a ring of iron. The coils are called high-voltage and low-voltage windings, or primary and secondary windings.

The primary winding is connected to the source of energy, and the secondary is connected to the load. The high-voltage winding is designed for the higher voltage, and has the greater number of turns.

The ring of iron is called the core. Each coil consists of a number of loops of round or rectangular wire. Several strands may be used in parallel but electrically insulated from each other, from the core and from the other coil. The core consists of thin sheets of high-grade silicon steel. The thickness depends somewhat on the frequency at which the transformer is to operate. The thickness commonly used for 60 cycles is approximately 0.014 in.

The primary function of a transformer is to transform electrical energy from one alternating voltage to another. To transform large amounts of energy with maximum efficiency, many factors must be considered in determining the materials, design, and arrangement of the primary and secondary coils and the core.

Ex.2 Match the words which are opposite in meaning:

high, thin, hot, small, long, visible, possible, increase, known, important, include, different;
unimportant, unknown, decrease, impossible, invisible, short, big, cold, thick, low, exclude, the same.

Ex.3 Find the following equivalents in the text Transformers :

1. состоит из изолированных катушек 2. катушки проволоки 3. обмотки низкого напряжения 4. первичная обмотка 5. количество витков 6. источник энергии 7. прямоугольная проволока 8. изолированные кабели 9. тонкие листы 10. высококачественная сталь 11. зависит от частоты 12. главная функция 13. передавать энергию 14. переменное напряжение 15.

расположение сердечника и катушки 16. большое количество энергии

Ex .4 Answer the questions :

1. What parts does a transformer consist of? 2. How are coils called? 3. What is the primary winding connected to? 4. What is the secondary winding connected to? 5. What winding has the greater number of turns? 6. What is the core? 7. May several strands be used in parallel? 8. What does the coil consists of? 9. What does the core consists of? 10. What is the main function of a transformer? 11. What does the thickness of the core depend on?

Ex.5 True or Faulse?

1. A transformer consists of two insulated coils of winding. 2. The primary winding is connected to the source of energy. 3. The coils are called cores. 4. The winding is called the core 5. Several strands are used in series. 6. Each coil consists of a number of turns. 7. The core consists of thin sheets. 8. The secondary function of a transformer is to transform electrical energy from a direct voltage to another.

Ex.6 Translate from Russian into English:

1. Катушки называются обмотками. 2. Катушка состоит из определенного количества петель. 3. Петли могут быть из круглой или прямоугольной проволоки. 4. Трансформатор состоит из изолированных катушек и проволоки. 5. Первичная обмотка подсоединена к источнику энергии. 6. Обмотка состоит из витков. 7. Провода изолированы друг от друга. 8. На превращение энергии влияет расположение катушки и сердечника. 9. Сердечник изготовлен из высококачественной кремниевой стали.

Ex .7 Read and translate the text

Transformer operation

Transformer is an electro-mechanical device for changing the ratio between current and voltage. All transformers operate on the principle of electromagnetic induction, which means crossing the conductor by magnetic lines of force. All transformers consist of three main parts: (1) Primary winding, which is connected to the mains; (2) Iron core, which concentrates magnetic lines of force and makes all of them cross the secondary winding; (3) Secondary winding, which is connected to the load of the transformer.

There are two practically used types of electrical transformers: (1) Stepping up transformers, in which the number of turns in the secondary winding is higher than the number of turns in the primary winding of the transformer, and (2) Stepping down transformers, in which the number of turns in the secondary winding is lower than the number of turns in the primary winding. Transformers are described by their operating power, operating frequency, and transformation ratio.

Operating power of a transformer is calculated as the product of current by voltage in its secondary winding under conditions of maximum loading. By operating frequency is usually understood the frequency in the mains for which the specific transformer is designed. Power transformers, designed for 60 cycles per second operation will not operate in the 50 cycles per second mains because of overheating and ultimate failure.

Encapsulated on-board transformers, designed for operation in the 400 cycles per second mains, in the 50 cycles per second mains quickly overheat and in some cases explode. Transformation ratio of a transformer is the ratio of the number of turns in its primary winding to the number of turns in its secondary winding. The operating of ideal or lossless transformers is described by the rule of transformation, which reads: ―The product of current by voltage in the primary winding is always equal to the product of current by voltage in the secondary winding. All real transformers have losses and beat during operation. The common source of losses is low-quality iron in the iron core of the transformers.

Ex.8 Answer the questions:

1. What do we use transformers for? 2. On what principle do all transformers operate? 3. What does electromagnetic induction mean? 4. What parts do all transformers consist of? 5. Where is primary winding connected to? 6. Where is secondary winding connected to? 7. What does the iron core of a transformer do? 8. How many types of transformers do we know? 9. In what cases do we use stepping-up transformers? What are they? 10. In what cases do we use steppingdown transformers? What are they? 11. Can you think of a transformer which is neither stepping-up nor stepping down? 12. What parameters are used for describing all transformers? 13. What is operating, or nominal, power of a transformer? 14. What is operating, or nominal, frequency of a transformer? 15. Will 60 cycles per second transformers operate in a 50 cycles per second mains? For what reason? 16. What will be the result of connecting a 400 cycles per second aviation transformer to the 50 cycles per second mains? 17. What is transformation ratio of a transformer? 18. What does the rule of transformation read? 19. To which transformers is the rule of transformation applicable? 20. What is the most common source of losses in all transformers?

Ex.9 Read and translate the dialogue

Aviation talk

Instructor : On board of modern airplanes there are up to eight hundreds of different transformers and great care is taken to reduce their weight and number to an absolute minimum. But do we have any reserves?

Student A: What do these transformers do? Why not to get rid of them altogether?

Instructor: Almost all on-board transformers are of a stepping-down type. All onboard electronic devices and their integrated circuits require + 12 volts DC for their operation. We have to step down the AC voltage from the mains up to this value and then to convert it into DC.

Student B: Can't we get round this problem end reduce the weight of iron? I've heard about practically lossless toroid magnetic circuits.

Instructor: This is a doughnut-shaped piece of magnetic material, together with several coils of current-carrying wire wound about the toroid. If the permeability of the magnetic material is high enough, the magnetic flux is completely confined within it.

Student A: Does the word "completely" mean that there are no losses?

Instructor: It does mean exactly this.

Student B: Then why not to use toroid transformers everywhere?

Instructor: There is one snag about toroid transformers: they are difficult to manufacture and very expensive.

Student A: Do we have any other devices in the primary winding circuit of a transformer?

Instructor: In the primary winding circuit of a power transformer we also find such devices as an on-off switch and a fuse.

Student B: We know something about them. The on-off switch switches the computer on or off. I can see this switch on the front panel of my computer. I am not so sure about the fuse. Does it protect the computer from overloads?

Instructor: It does. It is a small device which disrupts the primary winding circuit when the current exceeds the nominal value. Usually you can find it on the back panel of your computer.

Ex.10 Read and translate the text

Electric Motors and Generators

Electric motors and generators are used to convert mechanical energy into electrical energy, or electrical energy into mechanical energy, by electromagnetic means. A machine that converts mechanical energy into electrical energy is called a generator, and a machine that converts electrical energy into mechanical energy is called a motor.

Two related physical principles underlie the operation of generators and motors. The first is the principle of electromagnetic induction discovered by the British scientist Michael Faraday in 1831. If a conductor is moved through a magnetic field, or if the strength of a stationary conducting loop is made to vary, a current is set up or induced in the conductor.

The converse of this principle is that of electromagnetic reaction, first observed by the French physicist Andre Marie Ampere in 1820. If a current is passed through a conductor located in a magnetic field, the field exerts a mechanical force on it.

The simplest of all dynamoelectric machines is the disk dynamo developed by Faraday. It consists of a copper disk mounted so that part of the disk, from the center to the edge, is between the poles of a horseshoe magnet. When the disk is rotated, a current is induced between the center of the disk and its edge by the action of the field of the magnet. The disk can be made to operate as a motor by applying a voltage between the edge of the disk and its center, causing the disk to rotate because of the force produced by magnetic reaction.

The magnetic field of a permanent magnet is strong enough to operate only a small practical dynamo or motor. As a result, for large machines, electromagnets are employed. Both motors and generators consist of two basic units, the field, which is the electromagnet with its coils, and the armature, the structure that supports the conductors, which cut the magnetic field and carry the induced current in a generator or the exciting current in a motor. The armature is usually a laminated soft-iron core around which conducting wires are wound in coils.

Ex.11 Match the Russian and the English equivalents:

permanent magnet

электромагнитная индукция

electromagnetic means

электромагнитная реакция

basic units

якорь

exciting current

металлический стержень

armature

выделять

soft-iron core

электромагнит

electromagnetic induction

основные приборы

electromagnet

механическая энергия

force produced

физический принцип

10.

electrical energy

проводниковый контур

11.

dynamoelectric machines

постоянный магнит

12.

magnetic field

электромагнитные средства

13.

to pass through

ток возбуждения

14.

physical principle

электрический генератор

15.

mechanical energy

выработанная сила

16.

to exert

электрическая энергия

17.

electromagnetic reaction

динамо машины

18.

electric generator

электрический двигатель

19.

conducting loop

проходить через

20.

electric motor

магнитное поле

Ex.12 Answer the questions:

By means of what devices mechanical energy is converted into electrical energy?
How a machine that converts mechanical energy into electrical energy is called?
How a machine that converts electrical energy into mechanical energy is called?
What physical principles underlie the operation of generators and motors?
Who was the first to discover the principle of electromagnetic induction?
Who was the first to observe the principle of electromagnetic reaction?
What is the simplest of all dynamoelectric machines?
Is the magnetic field of a permanent magnet strong enough to operate big practical dynamo or motor?
What kinds of magnets are employed for large machines?
What do both motors and generators consist of?

Ex.13 Find the following equivalents in the text Electric Motors and Generators:

Превращать механическую энергию в электрическую; работа генераторов и двигателей; физический принцип; индукция; проводник; магнитное поле; электромагнитная реакция; ток проходит через проводник; медный диск; подковообразный магнит; работать как двигатель; постоянный магнит; электромагнит; обмотка; якорь; ламинированный стержень из мягкого металла.

Ex.14 Make interrogative and negative forms of the following sentences:

Electric motors and generators are used to convert mechanical energy into electrical energy.
A machine that converts mechanical energy into electrical energy is called a generator.
A machine that converts electrical energy into mechanical energy is called a motor.
The British scientist Michael Faraday discovered the principle of electromagnetic induction in 1831.
The French physicist Andre Marie Ampere first observed electromagnetic reaction in 1820.
The magnetic field of a permanent magnet is strong enough to operate only a small motor.
Electromagnets are used for large machines.
Motors and generators consist of two basic units.
The armature is usually a laminated soft-iron core.

Ex.15 Make sentences using these words and word combinations:

Energy; convert; mechanical; into; electrical; motors; used.
Generator; convert; energy; electrical; mechanical.
Induction; principle; discovered; scientist; Faraday.
Magnet; permanent; strong enough; small; operate; motor.
Machines; large; electromagnets; used.
Consist of; motor; basic units; field; armature.
Soft-iron; core; armature; made of.
Used; electric power systems; electric motors; electric generators.

Ex.16 Translate into English:

Механическая энергия превращается в электрическую при помощи генератора.
Электрическая энергия превращается в механическую при помощи электродвигателя.
Работа генератора и двигателя основана на двух физических принципах.
Принцип электромагнитной индукции был открыт британским ученым Фарадеем.
Ток проходит через проводник расположенный в магнитном поле. 6. Магнитное поле обычного магнита недостаточно для вращения больших двигателей.

7. Электромагниты применяются для работы больших двигателей.

8. Электродвигатели и генераторы широко применяются в промышленности.

Ex.17 Read the text and write out the more differences as you can between the aviation alternators and generators.

Alternators or Generators?

Electrical power in airplanes is created by either alternators or generators, and on many jets there are both. Alternators and generators convert rotational energy into electrical power, and for the most part, their functional differences are transparent to pilots. The fundamental difference is that generators produce direct current and alternators create alternating current.

In general, an alternator creates more power for its size and weight than a generator does and can also produce more power at lower rpm. That's why alternators are the norm on piston engines. Generators are the norm on turbine airplanes, at least until you get to the larger jets, because a generator can also function as a motor and, thus, as a starter-generator. Power is applied to the starter generator to spin the turbine for starting. Once the engine is up and running, the process is reversed and the unit creates electrical power, as much as 400 amps in some airplanes.

Most equipment in an airplane is designed to operate on direct current, so the power from an alternator is "rectified" into DC. Diodes, which are sort of an electrical one-way valve, do the rectifying on the typical airplane alternator. Most alternators have several diodes and can continue to produce usable power after the failure of one or two. Sometimes you can hear a new or increased humming or static noise in your headset when a diode or two has failed but the alternator is still producing some power.

The frequency of the alternating current from an alternator is relative to its rpm. In older-design airplanes, turbines in particular, a constant 400 hertz AC are most commonly used to operate some avionics, gyros and flight instruments. But other functions, such as heating elements in windshields, don't care about AC frequency, so they use "wild frequency" AC, which means the frequency varies as engine speed changes the rpm of the alternator.

Ex.18 Translate the sentences paying attention to Participle I

1. The scientist working at this design is well known. 2. Carrying out the experiment he made use of some new instruments. 3. These new devices are replacing their older equivalents. 4. Speaking about the new method of work the engineer told us many interesting details. 5. Radio occupies one of the leading places among the greatest achievements of modern engineering. 7. Being cooled water turns into ice. 8.The electric current passing through a wire will heat it. 9. Transistors contain no moving parts. 10. The scientist is carrying on an important research.11. Developing the new method they achieved good results.

Ex.19 Translate the following sentences into Russian:

1. Having improved this device they could use it for many purposes. 2. When making the experiment he made notes. 3. The vibrations of a voice speaking into the microphone of a telephone cause vibrations in an electric current. 4. This varying current is carried along a wire to a receiver. 5. Electronics in our country has developed into hundreds of research institutes and laboratories employing tens of thousands of people. 6. The Japanese power engineering develops much faster than that of the other developed countries, including the USA. 7. Having been discovered many years ago this metal found a wide application in industry only last year. 8. While being checked the motor showed good performance. 9. The man introducing this famous scientist is the dean of our faculty. 10. Cybernetics is gaining a growing importance.

Ex.20 Change the complex sentences given below according to the examples and translate them into Russian:

Example A :

While she was preparing for her physics exam she looked through all the notes of the lectures.

While preparing for her physics exam she looked through all the notes of the lectures.

1. When he was translating the article he used a dictionary. 2. While the student was working at the problem he made many experiments. 3. When the scientist was carrying out research in the field of nuclear physics he came to Dubna to work there. 4. When the worker was applying the new method of work he got better results. 5. While he was experimenting with this substance he was very careful. 6 When the engineer was improving the design he made many calculations. 7. While the man was describing this phenomenon he illustrated it with numerous examples. 8. When these scientists were working in our laboratory they obtained good results. Example B:

The scientists who are carrying out research into nuclear physics deal with most difficult problems.

The scientists carrying out research into nuclear physics deal with most difficult problems.

1. The scientist who is working at the method is well known. 2. The students who are listening to the audio lesson study at the correspondence department. 3. These postgraduate students who are watching the experiment work in our laboratory. 4. The worker who is repairing the machine is very skilled. 5. The engineer who is carrying out these investigations is a well-known inventor. 6. The students who are doing the laboratory work are from various faculties. 7. The workers who are building this house will soon finish their work.

UNIT V "RECTIFIERS AND AMPLIFIERS"

Vocabulary

7. to be grounded

7. быть заземленным

8. pulsations frequency

8. частота пульсаций (на выходе выпрямителя)

9. to filter out

9. отфильтровать, удалить с помощью сглаживающего конденсатора

10. to drive

10. заставлять двигаться,

заставлять протекать

11. rectifying diode

11. выпрямляющий диод

12. frame of reference

12. система координат

13. to plot

13. строить (кривую)

14. functional dependence

14. функциональная зависимость

15. origin

15. начало (системы координат)

16. axis (axes)

16. ось (оси)

17. conversion

17. преобразование

18. chopper

18. преобразователь

19. to obtain

19. достигать, получать

20. snag

20. трудность, препятствие

21. capacity

21. емкость, вместимость

22. getting rid

22. избавляться, освобождаться

23. cell

23. аккумулятор (элемент)

24. obvious

24. очевидный

25. adjusting ignition

25. регулирование зажигания

26. directivity patterns of onboard radar antennas

26. диаграммы направленности бортовых радиолокационных антенн

Ex.1 Read and translate the text

Rectifier

Rectifier is an electronic device for converting alternating current from the mains into direct current, necessary for computer circuits. All rectifiers operate on the principle of one-way conductivity of a rectifying diode. One-way conductivity means that the rectifying diode conducts current in one direction and does not conduct current in the opposite direction.

All rectifiers consist of three main parts: a power transformer, which is connected to the mains, a rectifying diode and a load. There are two main types of rectifiers. The first type is called half-wave rectifier, the second type is called full- wave rectifier. In a half-wave rectifier the secondary winding of the power transformer does not have any center tap and the frequency of pulsations at the output is fifty cycles per second. In a full-wave rectifier the secondary winding of the power transformer has a center tap, which is grounded, and there are two rectifying diodes.

The pulsations frequency at the output of a full-wave rectifier is one hundred cycles per second, which is much easier to filter out. During the first half-cycle of the AC voltage, the electro-motive force, developed in the secondary winding of the power transformer, drives the current from the ground to the rectifying diode. In this direction the diode conducts and the current flows through the load.

During the second half-cycle the electro-motive force changes for the opposite and drives the current from the diode to the ground. In this direction the diode does not conduct and no current flows through the load The frame of reference, used for plotting the functional dependence of current from times called the rectangular frame of reference. It consists of the origin and two axes - the axis of the variable (horizontal) and the axis of the function (vertical).

Ex.2 Answer the questions:

1. What are rectifiers for? Where are they used? 2. What is the principle of their operation? 3. What parts does a rectifier consist of? 4. How do we understand one-way conductivity? 5. What types of rectifiers do we know? 6. How do we call the first type of rectifiers? 7. Why these rectifiers are called half-wave? 8. What is the pulsation frequency at the output of these rectifiers? 9. What are advantages and drawbacks of half-wave rectifiers? 10. How do we call the second type of rectifiers? 11. Why these rectifiers are called full-wave? 12. What parts does a full-wave rectifier consist of? 13. How many diodes does a full-wave rectifier use? 14. What is the pulsation frequency at the output of a full-wave rectifier? 15. What are advantages and drawbacks of full-wave rectifiers? 16. How can we convert pulsating current into direct current? 17. What must we use for visual presentation of functional dependence of rectified current from time? 18. What are the main parts of the rectangular frame of reference? 19. What do we usually plot along the horizontal axis of the rectangular frame of reference?

Ex.3 Read and translate the dialogue

Aviation Talk

Instructor: Our present discussion is devoted to rectification and rectifiers. We know that rectification means conversion of AC (Alternating Current) into DC (Direct current).

Student A: Why not to have DC in the mains from the very beginning?

Instructor: There is one trouble with direct current - it is not transformable, which means that we can't step it down or step it up, according to our needs.

Student A: All car drivers know that there are devices called choppers, which do just this.

Student B: You mean that these choppers change the ratio between DC current and DC voltage?

Student A: They do just this. They transform direct current.

Instructor: But here we must not forget that choppers first convert DC into AC, change the ratio between current and voltage of the obtained AC, and finally they convert AC into DC, but with the ratio between current and voltage which we need.

Student B: There is one snag about rectifiers which I do not understand. After rectification we obtain pulsating current, but we need direct current. How do we solve this problem?

Instructor: The solution is very simple. We connect a condenser across the load. The higher the capacity of this condenser, the more direct, more smooth will become our direct current.

Student A: The operation of getting rid of all AC components out of our DC is called filtering or smoothing. Is it possible to obtain DC which does not contain any AC components?

Instructor: This type of DC can be obtained with the help of accumulators, batteries, cells and other chemical sources of current.

Student B: Once you have mentioned frames of reference and said something about the polar frame of reference. What is it for?

Instructor: The choice of the most suitable frame of reference depends on your variable. If you have to rotate something and observe what happens after each 10, 20, 30, and so on degrees of rotation, then your obvious choice will be the polar frame of reference.

Student A: It is very suitable for adjusting ignition moments of reciprocating engines.

Instructor: It is a very good example. Another example is directivity patterns of onboard radar antennas.

Vocabulary

amplifier

1. усилитель

to apply

2. прикладывать , подавать

amplification factor

3. коэффициент усиления

ratio

4. отношение (величин)

output power

5. выходная мощность

input power

6. мощность сигнала на входе, входная мощность

vacuum tube amplifier

7. усилитель на электронных

лампах, ламповый усилитель

solid state amplifier

8. усилитель на интегральных

схемах, твердотельный усилитель

plate

9. анод (электронной лампы)

10.

control grid

10. управляющая сетка

11.

filament

11. нить накала (катода)

12.

base

12. база, управляющий электрод транзистора

13.

collector

13. коллектор транзистора

14.

emitter

14. эмиттер транзистора

15.

amounts

15. величины

16.

in this respect

16. в этом отношении

17.

common kitchen water taps

17. обычные кухонные водопроводные краны

18.

valve

18. вентиль, клапан

19.

effortlessly

19. без видимых усилий, без затраты мощности

20.

feedback

20. обратная связь

21.

application

21. подача (сигнала)

22.

to turn into

22. превращать

23.

to be out of phase

23. быть в противофазе, изменяться в противоположных направлениях

24.

to feature

24. характеризоваться, демонстрировать

25.

low distortion

25. низкое искажение

26.

high stability

26. высокая устойчивость

Ex.4 Read and translate the text

Amplifier

Amplifier is аn electronic device or stepping up power of the signal. All amplifiers operate on the principle of controlling very large amounts of output power by very small amounts of input power, applied to the control electrode. Amplification factor of аn amplifier is calculated as the ratio of its output power to input power.

There are two main types of amplifiers: a vacuum tube amplifier, and a transistor, or solid state amplifier. The vacuum tube amplifier consists of plate, control grid, cathode, and filaments. Plate collects electrons, flying from cathode. Control grid controls current, flowing through the tube. Cathode emits electrons. Filaments heat the cathode, enabling the process of electronic emission. By their nature vacuum tubes are high voltage devices because voltages are high, but currents are low. Transistor amplifier consists of collector, base, and emitter. Base controls current flowing through the transistor. Emitter emits electrons. Collector collects electrons, arriving from emitter. By their nature transistors are current devices because currents are high, but voltages are low.

Mechanical, electric, and electronic devices, controlling very large amounts of output power by means of very small amounts of input power, applied to the control organ, are defined as valves. In this respect common kitchen water taps are typical valves because they control very large water flows practically effortlessly. Vacuum tubes and transistors do the same, but with flows of electrons. Feedback in amplifiers is defined as application of a part of output signal to the input Feedback is positive when the phases of input signal and of feedback signal are the same. Positive feedback turns amplifiers into generators. Feedback is negative when the feedback signal is out of phase with the input signal. Negative feedback amplifiers feature low distortion and high stability.

Ex.5 Match up the words which have an opposite meaning:

conductor, before, solid, alternating, early, high, receiver, new, important, advantage, little, light, possible, reliable;
impossible, unreliable, heavy, much, disadvantage, insulator, after, liquid, direct, late, low, transmitter, old, unimportant.

Ex.6 State to what parts of speech the following words belong:

visible, length, ordinary, different, amplifier, amplification, emission, radiation, semiconductor, scientific, industrial, gives, needed, atomic, microwave, unbelievable.

Ex.7 Form new words that contain the same roots:

amplifier, different, development, industrial, intensity, achievement, atomic, revolutionary, building, shorten, achievable, realize.

Ex.8 Form nouns adding the suffixes a)-age, b)-ment and c)-ity to the given verbs and adjectives and translate them:

Example:

a) to leak - течь b) to equip - оборудовать

leakage - утечка equipment - оборудование

с) stable - устойчивый stability - устойчивость

to use, to cover, to store, to break, to pass, to carry, to link, to stop, to assemble, to short(en);
to develop, to arrange, to achieve, to move, to measure, to improve, to manage, to establish, to excite, to require;
real, active, able, complex, dense, electric, intense, conductive, capable, special, flexible.

Ex.9 Answer the questions:

1. What are amplifiers used for? 2. What is the principle of their operation? 3. What does the control electrode of an amplifier do? 4. How is the amplification factor of an amplifier defined? 5. How many types of amplifiers do we know? 6. What are the main components of a vacuum tube amplifier? 7. What does the control grid of a vacuum tube amplifier do? 8. Why is it necessary to heat the cathode? 9. Why vacuum tubes are called high voltage devices? 10. What parts does a transistor amplifier consist of? 11. Why transistors are called current devices? 12. What does the base electrode of a transistor amplifier do? 13. What does the emitter electrode of a transistor amplifier do? 14. What does the collector electrode of a transistor amplifier do? 15. Is there anything in common between the base electrode of a transistor and the control grid of a vacuum tube? 16. How do we generally call devices controlling large amounts of output power by means of small amounts of input power? 17. What is feedback? 18. What types of feedback do we know? 19. What is positive feedback? What do we use it for? 20. What is negative feedback? 21. What are the results of negative feedback application? 22. What parameters of amplifiers are considered as most critical?

Ex.10 Read and translate the dialogue

Aviation Talk

Instructor: Presently it is really very difficult to find an on-board device without a built-in amplifier. This is especially true respective avionic equipment and onboard computers.

Student A: What requirements must these amplifiers satisfy?

Instructor: They must only amplify, that is they must step up only the amplitude of the signal, all other parameters must be left intact.

Student A: What are these parameters?

Instructor: They are phase and frequency characteristics, or responses. All modern amplifiers are negative feedback amplifiers, that is they use negative feedback to improve their quality

Student B: Does quality mean high fidelity sound?

Instructor: It does, but this terra is commercial and is not suitable for our purposes. In science sound quality is measured in percentages of distortion and in signal-to-noise ratios.

Student B: What is meant by distortion?

Instructor: By low or zero distortion amplifiers we understand an amplifier which increases only amplitude of the signal without adding or removing anything.

Student A: In other words, the amplifier must be absolutely impartial and amplify all frequency components of the signal equally well.

Instructor: But all real amplifiers distort, that is they add some new frequencies of their own and remove or diminish some frequencies of the signal. The summary percentage of such changes is called distortion.

Student B: You have also mentioned that signal-to-noise ratio influences sound quality. What is meant by this?

Instructor: By noise we mean low frequency hum due to bad filtering and high frequency hiss due to low quality transistors of the amplifier.

Student A: How can we expose a noisy amplifier?

Instructor: It's very simple. Just turn your volume control to the maximum and listen.

Student B: And what will we hear?

Instructor: You'll hear your amplifier at its worst.

READING COMPREHENSION

Solids, Liquids, and Gases

Matter is basically a substance that takes up space. All matter is a solid, liquid, or gas, and they are called the states of matter.

Everywhere a person looks, there are examples of solids: desks, chairs, windows, rocks, tissues, and much more. Examples of liquids: water, milk, juice, chocolate syrup, soda, and others. Examples of gases are harder to see, because they are invisible: the oxygen in the air, propane gas used for a grill, helium inside a balloon, and more.

Everything, all matter, can be identified as a solid, liquid, or gas.

Besides what they look like, there are many differences between solids, liquids, and gases. These differences are called characteristics. The characteristics of each state of matter are different. These characteristics determine if a substance is a solid, liquid, or gas.

A solid has a definite shape. It can be hard or soft, smooth or rough. Solids can come in all sizes. A solid can be large like the Statue of Liberty, or small like a marble. It can be very tiny like a bread crumb, or as big as a mountain, and everything in between. If small enough, solids can be held in a person's hand, and they are difficult to compress or push, or change shape.

The molecules of a solid are compact and close together, and nearly impossible to move through.

A liquid takes the shape of the container it is held in, and will fill the bottom of a container. Liquids usually have a smooth surface, but do not have a specific size. A person may be able to hold a small amount of liquid in their hand, but a liquid cannot be held like a solid. Liquids are less difficult to compress or push. It is much easier to move through a liquid than a solid.

The molecules of a liquid are spread out more than a solid, but less than a gas.

Finally, a gas has no shape, but can fill a container or any size or shape. It will fill an entire container as the molecules move. A gas cannot be felt in the hands like a solid or liquid. It has no surface or no particular size. It cannot be held in a person's hands, and it is easy to push or compress. A gas is the easiest to move through versus a liquid or solid.

The molecules in a gas are more spread out and move all the time. They are full of energy.

Water is the best example of a substance that can be a solid, liquid, or gas. Water by itself is a liquid. When water freezes it becomes a solid. If a container of water is heated it turns into a gas called water vapor.

There are many other substances that can be more than one type of matter, too. Ice cream is a solid until it melts, then it's a liquid. A moth ball is a solid, but it releases a gas that a person can smell across the room.

In summary, the different states of matter are called solids, liquids, and gases. The states of matter have different characteristics and examples of each can be found throughout the universe.

Matter is basically a solid, liquid, or gas that takes up:

A: Time

B: Space

C: Energy

D: Heat

Oxygen, helium, and propane are examples of a

A: Solid

B: Liquid

C: Gas

D: Mineral

Which of the following states of matter has a definite shape?

A: Solid

B: Liquid

C: Gas

D: None of the above

Which of the following states of matter takes on the shape of the container?

A: Solid

B: Liquid

C: Gas

D: All of the above

Which of the following states of matter has no surface or particular size?

A: Solid

B: Liquid

C: Gas

D: Both b and c

Which of the following describes the molecules in a solid?

A: The molecules are spread out and have lots of energy.

B: The molecules are spread out some, but less than a gas.

C: The molecules can easily be moved through.

D: The molecules are compact and close together.

Electric Current

Electric current is a flow of electric charge carried by moving electrons in a wire. The electric current is created by electrons or charges continuously moving through a path called an electric circuit. It flows from a power source like a battery or power station.

A closed circuit has a complete path for current to flow allowing the electric charges or electrons to flow through the wires of the circuit. An open circuit will not allow the electric charges or electrons to flow through the wires of the circuit. A switch can be used to open and close a circuit.

In a series circuit, the same current flows through each of the components. In a series circuit, each bulb will receive the same electrical charge, but if one goes out, all will go out. An example of a series circuit may be a string of Christmas lights. If any one of the bulbs is missing or burned out, no current will flow and none of the lights will go on.

Batteries are also a source of electric current usually used with a series circuit. The electric current from the battery flows in one direction to the component such as a radio, flashlight, or a toy.

Parallel circuits will have different amounts of current flowing through them. The same voltage is applied to parallel circuits, but different amounts of current will flow through the wires. Voltage is a kind of electrical force that makes electricity move through a wire and it is measured it in volts. The higher the voltage, the more current will tend to flow. A 12-volt car battery will normally produce more electric current than a 1.5-volt flashlight battery.

A parallel circuit example is the wiring of a house. There is a single power source supplying all the lights and appliances with the same voltage. However, if one of the lights burns out, the current will still flow through the rest of the house.

There are power plants that produce electricity for homes and businesses. Most power plants use coal to generate electricity, but some use wind, water, or natural gas. The power grid is the system connecting all of the power plants across the country. All the poles and wires along the highway and roads are a part of the power grid. A transformer can help in decreasing or increasing the voltage as the electricity travels to homes and businesses through transmissions lines. A meter is used to measure the amount of electricity used.

The electricity goes through wires to the service panel in a basement or garage, where breakers or fuses protect the wires inside a house from being overloaded. The electricity then travels through wires inside the walls to outlets and switches all over the house.

Conductors are made of materials that electricity can flow through easily. A material that is a good conductor gives very little resistance to the flow of electricity. The electricity can flow through a conductor very easily. Examples of conductors include water, trees, aluminum, copper, people, and animals.

Insulators prevent or block the flow of electricity. Insulators do not allow the flow of electricity and blocks the electricity from moving along its path. Examples of insulators are glass, rubber, porcelain, and plastic. Wires that carry electricity are covered with an insulator.

There are many steps involved when electric current flows from its source to its use.

Which of the following best defines a closed circuit?

A: Does not allow the electricity or electrons to flow through the wires, a switch is off.

B: Does not allow the electricity or electrons to flow through the wires, a switch is on.

C: Does allow the electricity or electrons to flow through the wires, a switch is on.

D: Does allow the electricity or electrons to flow through the wires, a switch is off.

Which of the following circuits have different amounts of electricity flowing through them?

A: Parallel circuits

B: Closed circuits

C: Open circuits

D: Series circuits

Which of the following is the system connecting power plants across the country?

A: Transformer

B: Power grid

C: Meter

D: Transmission line

Which of the following is used to measure electricity used by a home or business?

A: Voltage

B: Meter

C: Battery

D: Conductor

All of the following are examples of conductors EXCEPT:

A: Water

B: Glass

C: Aluminum

D: Copper

All of the following are examples of insulators EXCEPT:

A: Rubber

B: Porcelain

C: Plastic

D: Trees

Atoms and Electricity

Atoms are the basis for everything in the universe. All matter is composed of atoms. Solids are made of densely packed atoms while gases have atoms that are spread out. Protons, electrons, and neutrons are the basic parts of atoms. The parts of the atom include positive and negative charges and are responsible for the electrical charges known as electricity.

Electrons are the smallest of the three particles that make up atoms. They are located in an area that surrounds the nucleus of an atom. Electrons have negative charges. Protons, electrons, and neutrons are all related to electric charges.

Protons have positive charges. Protons are large and are found in the nucleus. Along with neutrons, they are grouped together in the center of the atom.

Neutrons are neutral and do not have a charge. They are large and are found in the nucleus grouped together with the protons.

Atoms start out with the same number of electrons and protons. Under certain conditions, electrons can be removed from an atom or added to an atom. Removing electrons would leave the atom with more positive than negative charges.

Electricity is the transfer of electrons from one atom to another. Electrons have a negative charge, they sometimes are attracted to atoms that have a positive charge. Electrons orbit in an area that surrounds the nucleus of an atom. Electrons then sometimes jump to the shells of nearby atoms as they orbit. This jumping or movement of electrons creates electric current. Current is what flows through electrical wires and powers electronics items, from light bulbs to televisions.

Electrical charges are created in power plants that goes through power lines to bring electricity into homes or businesses.

Static electricity is the imbalance of positive and negative charges in an object. Static electricity is created when electrons move from one place to another. Electrons can move more easily in some objects than in others. The rubbing of certain materials against one another can transfer negative charges, or electrons.

An example of static electricity is when a balloon is charged by rubbing it on the hair. It picks up extra electrons and has a negative charge. Holding it near a neutral object will make the charges in that object move. This is an example of static electricity. Another example involves clothing is in a dryer. The fabrics rub together and there is an exchange of electrons from the surfaces of the clothing. They are then attracted to each other and cling together. The crackling sound heard comes from the electrons being pulled away from each other when the clothes are separated.

In summary, without atoms and the interaction between electrons, protons, and neutrons, it would not be possible to have electricity. The main parts of an atom included protons with positive charges, electrons with negative charges, and neutrons with no charge. Electrical current is produced in power plants and is then transferred to homes and businesses through power lines. Finally, a common form of electricity is static electricity which often occurs when electrons rub off and on various objects and interact with each other.

Which of the following parts of an atom have no charge?

A: Proton

B: Electron

C: Neutron

D: Nucleus

Which of the following parts of an atom have a positive charge?

A: Proton

B: Electron

C: Neutron

D: Nucleus

Which of the following parts of an atom have a negative charge?

A: Proton

B: Electron

C: Neutron

D: Nucleus

Which of the following is the transfer of electrons from one atom to another?

A: Electricity

B: Static electricity

C: Both a and b

D: Neither a nor b

Which of the following flows through electrical wires and powers electronics items, from light bulbs to televisions?

A: Static electricity

B: Neutron current

C: Nucleus charges

D: Electric current

Which of the following causes the crackling sound heard from the electrons being pulled away from each other when the clothes from a dryer are separated?

A: Static electricity

B: Neutron current

C: Nucleus charges

D: Electric current

Magnetism

Magnets are easy to use, safe, and fun. Two magnets snap together and can stick like glue. Certain objects push or pull on things because they are magnetic. Magnetism is another property of some kinds of matter.

A magnet has a north and south pole. The north pole of a magnet will attract the south pole of a magnet. The north pole of a magnet will repel the north pole of a magnet, and the south pole will also repel the south pole. In short, like poles repel, and unlike poles attract.

Two different kinds of permanent magnets are called bar magnets and horse show magnets.

The area surrounding a magnet is called its magnetic field. The magnetic field of a magnet is an invisible field which is created by its magnetism. To ancient people, magnetism probably seemed like magic. The force for magnets to attract or repel each other or to attract other objects is caused by moving electrons.

The Earth also contains magnetic materials and behaves like a gigantic magnet. The north pole of a magnet will point approximately to the Earth's North Pole and south pole of a magnet to the Earth's South Pole. A compass has a magnetic tip on the needle which points towards the North Pole. Compasses are used to help people prevent getting lost such as hikers or captains on a ship, especially many years ago when there was no GPS or maps to help guide them.

A magnet may also be used to convert an unmagnatized piece of magnetic material, such as an iron nail, into a magnet. This is done by rubbing it with the magnet. This is called magnetization. Magnets made this way are called temporary magnets because they eventually lose their magnetism.

Another method in creating a temporary magnet is by using electricity. This can be done by wrapping an iron nail with a coil of wire. By passing electricity through the coil of wire the iron nail will become a temporary magnet or an electromagnet. The strength of the electromagnet depends on the size of the electric current and the number of times the coil is wrapped around the nail. If the electricity stops flowing through the coil the nail will no longer be magnetic.

There are many uses for permanent magnets and temporary magnets like an electromagnet. Electric appliances with electric motors use magnets to turn electricity into motion. Other examples include electric toothbrushes, fans, lawnmowers, and anything else containing a motor.

Magnets are used to hold doors closed, such as in refrigerators, kitchen cabinets and others. Magnets are also used to read and write data on a computer's hard drive or on old-fashioned cassette tapes. There are more magnets in headphones and stereo speakers which help to turn stored music back into the sounds you can hear.

In summary, magnetism is another property of some kinds of matter. There are two poles to a magnet, the south pole and the north pole. Like poles repel and unlike poles repel. There are two different kinds of magnets, temporary and permanent. A temporary magnet can be made by using electricity. All magnets contain an invisible electromagnetic field which surrounds the magnet. There are many uses for magnets, from holding doors closed to helping music sound better with the magnets inside of speakers.

Which of the following statement is true?

A: Like poles attract, unlike poles repel.

B: Like poles repel, unlike poles attract.

C: Like and unlike poles attract.

D: Like and unlike poles repel.

The invisible field surrounding a magnet is called

A: A magnetic field

B: An electromagnet

C: The force field

D: None of the above

Moving __________ is the cause of magnets repelling or attracting each other or other objects.

A: Protons

B: Electrons

C: Neutrons

D: Molecules

Which of the following is a temporary magnet?

A: Bar magnet

B: Horseshoe magnet

C: Electromagnet

D: North pole

Which of the following statements is false?

A: The strength of the electromagnet depends on the size of the electric current and the number of times the coil is wrapped around the nail.

B: Certain objects push or pull on things because they are magnetic.

C: Electric motors use magnets to turn electricity into motion.

D: A magnet cannot be used to convert an unmagnatized piece of magnetic material such as an iron nail, into a magnet.

Light

Light is everywhere, and without light, life would not exist. Light waves travel from place to place. Light is a form of energy that can be seen when it is reflected off the surface of an object. It is visible to the human eye and is responsible for the sense of sight. Light waves travel through the air from place to place and do not carry matter. Light travels at a speed of 186,000 miles per second. It takes about 8 minutes for the light from the Sun 93 million miles away to reach the Earth. Light is believed to travel faster than anything in the universe. Light is unable to travel through solids, but it can travel through liquids and gases.

Light can travel through some objects very easily. If light can pass through an object like air, water, or glass, the object is transparent. When an object allows light to bounce off it or reflect the light, the object is opaque. Finally, translucent objects cause light to scatter and go in different directions.

There is three ways light can be controlled or changed. Reflection occurs when light waves bounce off a surface. This allows the surface to be visible, and an object can be seen. Without light reflection, people could not see things. The light from a lamp helps a person see the words in the book. Another example of reflection is when the Sun gives off light, but the moon cannot. The light from the Sun reaches the moon and it shines in the night sky. The light reflects off the surface of the moon.

Refraction is the bending or turning of light, changing its path. This can occur when light travels through water or other transparent objects. The direction and speed of the light changes. Glasses and telescopes are examples. Another example of refraction is a prism. When light travels through the prism it changes direction. On the other side, various colors result at different angles. The light has been refracted.

Blocked light is blocked by non-transparent objects. Light can be blocked with a sun visor, umbrella, or the moon during an eclipse. Another example of blocked light will cause a shadow of the blocked object to appear. Therefore, a person can see the shadow of their body on the sidewalk.

There are several other examples of light being changed or used. Light waves or energy can be changed in many ways. The light energy from the Sun can be turned into electricity and is used by plants to make food. The lenses in glasses people wear are curved, which changes the light waves and help them see better. When light reflects off a mirror, people can see themselves. When a pencil is placed into a glass of water, the pencil will seem like it is broken into two pieces. Because the light is traveling through the water, there is refraction, and the light bends causing the pencil to look like it is in two pieces.

Nearly everything that can be seen depends on light in some way. It takes light for TVs, video games, and computers to work. Also, without light, a person would not be able to see the beautiful colors of a rainbow, a sunset, a sunrise, or the full moon in the night sky.

Which of the following occurs when light waves bounce off a surface?

A: Refraction

B: Reflection

C: Transparency

D: Blocked light

If light can pass through an object like air, water, or glass, the object is which of the following?

A: Translucent

B: Transparent

C: Opaque

D: Blocked

Which of the following is an example of a non-transparent object?

A: Moon

B: Sun visor

C: Umbrella

D: All the above

What happens when light travels through a prism?

A: It is blocked

B: It is reflected

C: It is opaque

D: It changes direction

Which of the following objects cause light to scatter and go in different directions?

A: Translucent

B: Transparent

C: Opaque

D: Blocked

The bending or turning of light as it changes its path is which of the following?

A: Reflected

B: Blocked

C: Refracted

D: None of the above

Light and Sound

Light and sound is found everywhere. Light and sound waves travel from place to place and can be seen and heard. Light is visible to the human eye and is responsible for the sense of sight. It is a form of energy we can see when it is reflected off the surface of an object.Sound is a mechanical vibration that can pass through solids, liquids, and gases and can usually be identified by the sense of hearing.

Light waves travel through the air from place to place and do not carry matter. Light is believed to travel faster than anything in the universe. It travels at a speed of 186,000 miles per second. Light is unable to travel through solids, but it can travel through liquids and gases.

There are two properties of light. The first property of light is called reflection. Reflection is when light bounces off a surface which then allows the object to be visible to the eye. For example, when the moon is seen in the sky, it is because the light from the sun reflects off the surface of the moon. A light ray comes off a surface at an equal angle to the angle at which it struck the surface.

The second property of light is called refraction. Refraction is when a ray of light passes from a transparent medium to another transparent medium such as from air to water, it changes speed and the way it bends.

For example, when a pencil is placed into a glass of water, the pencil will seem like it is broken into two pieces. Because the light is traveling through the water, there is refraction, and the light bends causing the pencil to look like it is in two pieces. Another example of refraction is the use of eyeglasses to improve a person's vision. Using a glass that is curved at a certain angle the vision of a person is corrected by the way light is refracted in the eye.

All sounds are different, but one thing in common is that sounds are created by something that vibrates. Sound wave vibrations can travel through solids, liquids, and gases. Sound waves travel through solids much faster than through liquids or gases, and faster in liquids than gases.

The molecules that make up a solid are closer together allowing the sound to travel faster.Molecules are the substances that make up solids, liquids, and gases. In a liquid, the molecules are farther apart, so the sound waves travel slower. In a gas, the molecules are spread farther apart so the sound waves travel much slower. A sound traveling through a solid can be better heard than traveling through a gas.

For example, a vibrating speaker collides with the molecules in the air passing along the energy and creating sound waves. This is why music can be heard from the speakers. When there are no molecules in the air, like in space, the sound could not be heard. The speed of sound travels much slower than the speed of light. It normally travels in air at about 1200 feet per second.

In summary, light and sound is everywhere. Light is a form of energy we can see when it is reflected off the surface of an object. Sound is a mechanical vibration that can pass through solids, liquids, and gases. Reflection and refraction are two properties of light. Sound travels through solids much faster than through liquids and gases. Molecules, which make up all objects, are closer together in a solid allowing the sound to travel faster. Light travels much faster than sound.

Which of the following is a mechanical vibration?

A: Sound

B: Light

C: Water

D: Reflection

Which of the following statements is true?

A: Light travels at the same speed as sound.

B: Sound travels faster than light.

C: Light travels faster than sound.

D: The speed of light and sound depends on the temperature. 3) Which of the following best defines reflection?

A: Light bounces off a surface which then allows the object to be visible to the eye

B: A ray of light passes from a transparent medium to another transparent medium

C: A ray of light passes from a solid to a gas

D: Light bounces off the surface of the sun

Which of the following will sound travel faster?

A: Air

B: Water

C: Pudding

D: Wood

Which of the following makes up the substances of solids, liquids, and gases?

A: Molecules

B: Minerals

C: Vibrations

D: None of the above

Which of the following explains light waves bending as it passes through water?

A: Reflection

B: Refraction

C: Molecules

D: Energy

Wind Energy

Wind can generate electricity and thus provide an additional source of energy for human use. Harnessing the energy of the wind means using the air which flows naturally in the earth's atmosphere. The kinetic energy of the wind is captured by the blades of a wind turbine. Kinetic energy is the energy a body has just by moving. This kinetic energy is turned into mechanical energy. The mechanical energy spins a generator creating electricity.

Wind is a renewable form of energy. That means it will never run out. There are three types of wind power. Electric utilities or power system operators provide utility-scale wind. Its turbines deliver more than one hundred kilowatts of electricity to the power grid and then to the user. A home, farm or small business would receive power from turbines of one hundred watts or smaller. This is called distributed or small wind. Wind turbines can be set up on the continental shelf in the ocean. This is called offshore wind.

People often think that a windmill and wind turbine are the same thing. A windmill cannot generate electricity even though it produces mechanical energy. Windmills have been used for many years to grind grain and pump water. The modern wind turbine has over eight thousand parts and is much more complicated than a windmill.

Often wind turbines are put together in an open windy area. This group is called a wind project or farm. The group works as one to produce electricity for use by people. They are connected so that the electricity travels to the power grid. A power grid is a network for getting electricity and sending it to users. Distribution lines which are small collect the electricity at the site and pass it along to larger transmission lines called network transmission lines. The electricity can be sent over long distances and then to users through smaller distribution lines at the other end.

To develop a wind farm or project requires several steps. A site which can capture a great deal of wind must be located. Usually, this spot is on private land. The landowner leases the land to the project developer. Before a developer leases land, he must make arrangements with a power company, borrow enough money to fund the project, order the turbines and hire a construction company.

Wind energy has many benefits. The projects bring money into low-income rural areas around the country. The business is now supporting one hundred thousand jobs. The job title 'wind turbine technician' is widely advertised. Wind energy is an easy crop for farmers to sell. Farmers do not have to depend on water or sun to make money. Farmers received two hundred forty-five million dollars in lease payments from developers in 2016. The companies also pay local taxes which help provide schools and other community needs.

Because wind power does not produce pollutants, health care costs have gone down. It cuts down on asthma and lung disease. The Harvard School of Public Health states that 7.6 billion dollars in medical costs were saved in 2016. The American Lung Association is in favor of wind energy because it keeps the air clean and free from pollution. The organization has a Healthy Air Campaign to promote the use of wind energy.

Wind energy keeps energy bills down for the consumer. It is becoming more competitive with other types of energy in terms of cost. Wind farms leave most of the farmer's land free for other uses while providing a steady income. In the last seven years, the average price of wind power declined by two-thirds.

1) Which of the following is a true statement?

A: Wind is not a renewable form of energy.

B: Most wind farms are on public land.

C: Wind farms are usually on private land.

D: The American Lung Association is not in favor of wind energy.

2) Which of the following is a true statement?

A: Wind turbines can be set up in the ocean.

B: A windmill and a wind turbine are the same.

C: Mechanical energy is created just by a body's motion.

D: Wind energy has very few benefits for a person's health.

Which of the following is the name of the type of turbine used by the large utility companies to provide electricity using more than one hundred kilowatts?

A: Small wind

B: Offshore

C: Utility-grade

D: High turbine

Which of the following is the name for a large group of wind turbines connected together in a field?

A: Wind farm

B: Turbine production center

C: Wind factory

D: Transmission center

Which of the following is the network to which the electricity travels from the wind turbines out in the field?

A: Power house

B: Power grid

C: Power factory

D: Power storage unit

Which of the following is a false statement?

A: Wind power is now creating many jobs.

B: Wind power has caused medical bills to decline.

C: Farmers do not make much money from having wind turbines on their property.

D: Farmers make easy money by having wind turbines on their land.

Heat Energy

It can be found everywhere because matter is found everywhere. It is heat energy. Heat energy results from the movement of atoms, molecules, and ions in solids, liquids, and gases. Heat energy is everywhere from volcanoes to sheets of ice and in the body. All matter contains heat energy. Heat energy can be transferred from one object to another due to the difference in temperature between the two objects. The difference is called heat.

For example, an ice cube and a glass of juice both have heat energy. When the ice cube is placed into the warmer glass of juice, the juice will transfer some its heat to the ice cube. The juice heats the ice cube. Eventually, the ice cube will melt, and the two substances will be the same temperature. When the same temperature is reached it is called thermal equilibrium.

Matter makes up everything in the universe, has mass and volume, takes up space, and exists either as a solid, liquid, or gas. Tiny particles called atoms, molecules, and ions make up the matter, and the particles are constantly in motion, vibrating back and forth. The movement of the particles creates a form of energy which is called heat or thermal energy.

The particles in solids are tightly packed together and only vibrate, in liquids, they vibrate and move around and slide into each other, and in gases, the particles move freely and rapidly with random motion.

The higher the temperature the more energy the particles will have. The energy can then easily be transmitted to other particles that are at a lower temperature. For example, a gas has fast-moving particles that can combine with slower moving particles. A transfer of energy takes place to the slower moving particle which increases the speed of that particle. As the collision of particles occurs, an area of high energy will slowly transfer across the material until thermal equilibrium is reached.

The fast-moving particles can rouse the nearby particles, and if heated sufficiently, the movement of particles in a solid increase and overcomes bonds that hold the particles together. The substance can then change from a solid to a liquid; in other words, it melts. If there is a further increase in the particles, the melted substance can then reach a stage where the substance changes into a gas; in other words, it evaporates.

There are three ways of transferring heat energy: convection, conduction, and radiation. Convection transfers heat energy through gases and liquids. Air is heated, the particles gain heat energy and allow the particles to move faster and further apart. The movement eventually creates a circular flow called a convection current. A convection current is used to heat a room using a radiator.

Conduction transfers energy into solids. The moving particles of a warm solid increase heat energy of particles in a cooler material. Since particles are closer together, solids conduct heat better than liquids or gases. An example is a fire used to ignite a candle; the fire spreads the heat through a solid material.

Finally, radiation is a method of heat transfer that does not require a particle to carry the heat energy. Heat is transferred in infrared waves, which is part of the electromagnet spectrum. Heat is released or radiates from all directions from the hot objects. When this happens, the heat energy carried by the waves can either be absorbed or reflected. The heat produced by the Sun is transferred to the Earth by radiation.

In summary, heat energy results from the movement of atoms, molecules, and ions in solids, liquids, and gases. There are three ways of transferring heat energy, convection, conduction, and radiation.

All the following are methods for transferring heat EXCEPT:

A: Equilibrium

B: Convection

C: Radiation

D: Conduction

Which of the following substances are the particles packed tightly together?

A: Liquids

B: Solids

C: Gases

D: All the above

Which of the following best defines thermal equilibrium?

A: Two substances' temperatures remain the same during transfer of heat energy

B: The temperatures of substances never change during the transfer of heat

C: All substances will eventually reach the same temperature

D: Two substances reach equal temperatures during the transfer of heat energy 4) Which of the following methods of transferring heat create a circular flow?

A: Radiation

B: Convection

C: Conduction

D: Both A and B

All the following are the particles that make up matter EXCEPT:

A: Atoms

B: Ions

C: Cells

D: Molecules

Which of the following methods of transferring heat transfers energy into solids?

A: Radiation

B: Convection

C: Conduction

D: Equilibrium

Static Electricity

The build-up of an electric charge on the surface of an object is called static electricity. The charges of the electricity remain in one area, or remains 'static', and they do not move or 'flow' to another area. Static electricity can be observed every day such as when a person rubs their feet on the carpet and then gets zapped when they touch something.

It is static electricity that builds upon the surface of the skin and then it discharges onto what is touched. Other examples include the hair on a person's head when it sticks straight up or when pant legs keep sticking to a person's legs. It is all static electricity that builds up on the surface of the objects.

Static electricity comes from the interaction of atoms. Atoms are made up of tiny particles called protons, neutrons, and electrons. The nucleus of an atom is made up of neutrons and protons, and the electrons spin on the outside of the nucleus. The static electricity is created when the electrons from one object move to the other object. One object has a negative charge and the other has a positive charge. When objects are rubbed together quickly, there will be a greater charge.

Items with negative and positive charges, different charges, will attract, while items with similar charges will push away from each other, just like with a magnet. An example is when a person slides down a slide, and the friction of sliding causes a positive charge to be built up on each hair. Each hair has the same charge meaning they will try to push away from each other causing them to stand up.

In the same manner, if the skin is charged with static electricity and the person touches metal, which is a good conductor of electricity, it will quickly discharge the static electricity creating a zap or sometimes a small spark.

There are several applications for static electricity in the real world, and not just for getting zapped by touching things. It is used in printers and copying machines. The static electric charges attract the ink, or toner, to the paper. Static electricity is also used for paint sprayers, air filters, and dust removal.

Though static electricity can be helpful, it can also cause damage. For example, some electronic chips like those inside computers are very sensitive to static electricity. Special bags are often used to store electrical components, so they are not damaged or destroyed by the static charges. In addition, people who work with these kinds of electronics must wear special straps that keep them 'grounded'. In this way, they do not build up a static charge and cause damage to the electronic components.

There is very little current with static electricity and it only lasts for a short period of time, though it can measure thousands of volts. Overall, it has very little power or energy. However, lightning is a powerful and dangerous example of static electricity, and the temperatures in a lightning bolt can hit 50,000°F. Finally, static electricity builds up much more and faster on a dry, non-humid day.

In summary, static electricity is created due to the interaction between the particles of atoms of different objects. Most times, static electricity does not cause many problems and it can be helpful, but it may damage some electronic components and as part of lightning strikes it can be deadly.

All the following are tiny particles that are parts of atoms EXCEPT:

A: Neutrons

B: Protons

C: Electrons

D: Molecules

Fill in the blanks:

Items with negative and positive charges will ___, while items with similar charges will ___ from each other.

A: Attract/push away

B: Push away/attract

C: Neutralize/push away

D: Neutralize/attract

All the following are examples of the application of static electricity in the real world EXCEPT:

A: Printers

B: Copying machines

C: Candles

D: Paint sprayers

Which of the following are very sensitive to static electricity?

A: Air filters

B: Magnets

C: Electronic chips

D: Dust removal machines

Which of the following weather conditions is conducive for static electricity?

A: Dry, non-humid day

B: Rainy, warm day

C: High humid day

D: Cool, non-humid day

Which of the following is the approximate temperature in a lightning bolt?

A: 50,000°F

B: 5,000°F

C: 500,000°F

D: None of the above

Список использованной литературы

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Electronics [Электронный ресурс]. – Режим доступа: https :// sciencing . com / why - does - magnet - attract - iron -4572511. html - (Дата обращения: 19.09.2018).
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Historical Introduction [Электронный ресурс]. – Режим доступа: http :// farside . ph . utexas . edu / teaching /316/ lectures / node 12. html - (Дата обращения: 01.07.2018)
Language _ arts [Электронный ресурс]. – Режим доступа: http :// www . softschools . com / language _ arts / reading _ comprehension / science / - (Дата обращения: 04.08.2018)