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The Past and the Future of the Laser 3 глава
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EXAMPLE 1: The instructor said to the students, "Switch off the power immediately".
The instructor told the students to switch off the power immediately.
1. Sasha said to Sergey, "Connect the ammeter to the circuit".
2. Alice asked Oleg, "Control the electrical pressure in the circuit".
3. Denis warned Natasha, "Take the bulb out of the socket first".
4. Kate reminded Oleg, "Measure the potential difference across two
points in a circuit".
EXAMPLE 2: Mr. Pavlov said to the students, "Don't increase the pressure in the system".
Mr. Pavlov told the students not to increase the pressure in the system.
1. Alice said to Paul, "Don't switch on the power".
2. Natasha warned Oleg, "Don't connect the contacts of the circuit".
3. Alice asked Susan, "Don't use faulty electrical devices in your work".
4. Nick ordered Ann, "Don't touch the socket".
V. Explain why these things happen.
EXAMPLE: water / to flow down - wheel / to turn
The water flows down. - This makes (lets) the wheel turn.
temperature / to increase - liquid / to expand
valve / to be open - water / to flow in the system
bulb / to burn out - you / to change it
contact / to be closed - current / to flow in the circuit
leads / to be connected - current / to pass through the conductor
batteries / to discharge - electric car / to stop
VI. a) What do these people want others to do for them? Fill in the
table.
EXAMPLE: Oleg: - Students, switch on the power, please.
| Oleg | would like | them | to switch on |
| (the students) | the power. | ||
| Alice | want(s) | … | … |
| Helen | wish(es) | … | … |
| Roman | desire(s) | … | … |
| Teacher | need(s) | … | … |
| Natasha and Rita | expect(s) | … | … |
| We | ... | … | … |
1. Alice: - Nick, test the bulb.
2. Helen: - Oleg, carry out all the necessary calculations.
3. Roman: - Olga, describe the work of a transformer.
4. Teacher; - Helen, draw a simple circuit, please.
5. We: - Alex, complete the measurements.
6. Natasha and Rita: - Please, turn off the power.
b) What would you like your friends to do for you? Give as manyversions as you can.
VII. a) Say what things these people don't want others to do.
EXAMPLE: Students: - Pavel, don't switch off the lights, please.
| Students I Nina and Alice | don't | want wish desire need expect | him (Pavel) to switch off the lights. |
| Olga Nick | doesn't | ||
| Denis Sasha | wouldn't | like |
1. I: - Students, don't touch the wiring.
2. Nina
and Alice: - Peter, don't connect the voltmeter to the circuit.
3. Olga: - Marina, don't turn off the whole current.
4. Nick: - Freshmen, don't apply the old method of calculations.
5. Denis: - Professor, don't switch off the ceiling lights, please.
6. Sasha: - Don't turn the bulb out of the socket.
b) Name 5 things that you wouldn't like your friends to do.
VIII. These two sentences have a different structure but the same
meaning. Change the structure of the sentences below so as to keep
their meanings unchanged.
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EXAMPLE: This allowed him to follow the rules. This allowed the rules to be followed.
1. This device enables the students to measure the current in the
circuit.
2. This analysis permitted them to obtain new data.
3. The information enables us to predict the properties of the new
substance.
4. This result forced them to check the circuit again.
5. Modern equipment caused us to introduce new methods.
6. The tutor would like us to complete the coursework on time.
IX. Restore the original sentences.
1. this device, an electrical charge, enables, to be built up and stored 2.I, you, out of the socket, told, to remove, the bulb
3. this, the current, makes, flow, through the circuit
4. she, him, the contacts, wanted, of the circuit, to connect
5. the transformer, to be increased or decreased, the voltage, allows
6. one, the current, can assume, in one direction, to flow, only
X. Correct mistakes.
1. Nick asked Boris turn the bulb clockwise.
2. New data let us to carry out another experiment.
3. Mr. Pavlov told the students to not use a broken voltmeter.
4. The flow of water makes the wheel to turn.
5. His discovery allowed an invention be made.
6. Roman was asked test the bulb.
7. Alice expected Paul connect the contacts of the circuit.
8. This fact didn't let Andrew to break the rules.
9. The assistant warned them not create a magnetic field.
XI. Translate the sentences into English using your active vocabulary.
1. Лампочка перегорела, и я хочу, чтобы ты ввинтил в патрон
новую.
2. Мне нужно, чтобы он сейчас отключил электричество.
3. Вы хотели бы, чтобы я объяснил вам основы электричества?
4. Выпрямитель позволяет электрическому току протекать
только в одном направлении.
5. Этот прибор позволяет нам измерить напряжение в цепи.
6. Если контакт открыт, ток не проходит по цепи.
7. Преподаватель попросил начертить схему электрического
прибора.
8. Магнит заставляет ток менять направление.
Reading and Speaking
I. Are you good at electricity? Match the objects with their symbols. cell, 6V battery, wire, bulb, switch, ammeter, voltmeter, ohmmeter
II. Practise reading these words.
filament ['filemant] insulator ['insujleite] kinetic [kai'netik] alternating [,alte'neitin] frequency ['fri:kwansi]
2 Часть 2
III. Look at the title and the picture and say what information the text gives. Read the text attentively for the details.
Electricity Basics
Electricity is something we do not notice until we do not have it. However, few people understand what it is and still fewer can explain it. Let us try it anyway.
So, what is electricity? Electricity is simply a movement of charged particles through a closed circuit. The electrons, which flow through this wire, carry a negative charge. A lightning discharge is the same idea, just without the wire.
Electricity is made by converting some form of energy into flowing electrons at the power plant. The type of power plant depends on the source of energy used: thermal power (coal, oil, gas, nuclear, underground steam), solar power (photovoltaic), kinetic power (water, wind) and chemical power (fuel cell).
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After it is made, electricity is sent into a system of cables and wires called a transmission grid. This system enables power plants and end users to be connected together.
The basic notions in electricity include the following.
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| Tungsten Filament High Resistance |
An Amp (A) is a unit measure of the amount of current in a circuit. An ammeter permits the current to be measured.
| Molybdenum Wires Low Resistance Glass Bulb Very High Resistance (Insulator) |
The pressure that forces the current to flow is measured in Volts (V). A transformer is used to change the voltage of electricity. This allows electricity to be transmitted over long distances at high voltages, but safely used at a lower voltage.
A Watt (W) is a unit measure of electric power that depends on amps and volts. The more watts the bulb uses the more light is produced. Watts = Volts x Amps.
| a) power station, b) transformer, c) rectifier, |
| d) overhead conductor wires, e) magnetic field, f) capacitor, |
An Ohm (0) is a unit measure of materials resistance to a flowing current. The filament in this light bulb glows because its high resistance makes it hot. Low resistance of the support wires does not let them glow. The glass has a resistance so high that it does not allow the current to move through it - this property makes glass a good insulator.
IV. Provide answers to the questions below.
1. What is electricity and an electron?
2. How is electricity produced?
3. What types of power plants do you know?
4. What is the function of the transformer?
5. How does the light bulb work?
6. Glass is a poor insulator, isn't it?
V. Complete the table with the data from the text.
| Symbol | Unit | Electrical Notion | Measuring Device |
| 1. | ammeter | ||
| 2. | Volt | ||
| 3. | resistance | ||
| 4. W |
VI. You are taking your exam in Physics. Your examination card says: Electricity, its definition and basic notions. Your partner is your examiner. Answer his questions and try to get a good mark.
- Well, what is electricity?
- Oh, electricity is...
VII. What new information have you learnt about electricity from the text? What things have you already known?
Further Reading
I. Practise reading these words.
| wound [waund] primary ['praimeri] |
rectifier ['rektifaie] wind [waind]
II. Do you know what DC and AC mean? How are they produced? What are their functions? What do you know about the transformer?
III. Skim the text to find out the functions of these things:
IV. Read the text carefully for more information on electricity.
Electricity Basics (continued)
There are two different kinds of electrical current. One is called direct current because electrons are made to move in one direction only. It is usually abbreviated to DC. This kind of electricity is produced by a battery.
AC stands for alternating
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current, which is generated by power stations for domestic and industrial use. The wires in the centre of the generator rotate past the North and South poles of the (red) magnet. This movement forces the electrons in the circuit to reverse the direction of their flow. The number of these alterations (or cycles) per second is known as frequency.
As domestic supply requires alternating current it is therefore necessary to change it to direct current inside most electrical appliances. A rectifier allows AC to be converted into DC.
Power stations are designed to provide electrical energy to large housing developments. This causes the necessity to transmit power from its source, the generating station, to wherever it is required for use, which may be far away, with minimal energy losses. It is cheaper and easier to carry a very high voltage but low current, over long distances. It can be done with the help of thinner overhead conductor wires, with an air gap between them to act as an insulator,
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A transformer is used to increase or decrease the voltage of an electric power supply. This is a static machine since it has no moving parts. It consists of two coils of wire that are wound around a soft iron core. The coils are called windings, one is the primary, or input winding, and the other is the secondary, or output winding.
When current passes through the primary winding, a magnetic field is created around the iron core, which induces a voltage in the secondary winding. If the number of turns in the secondary winding is greater than that in
the primary winding it is a step-
up transformer and the output
voltage is greater than the input voltage. And vice versa, a step-down transformer enables the input voltage to be reduced.
A device, which allows an electrical charge to be built up and stored for some time is known as a capacitor (or a condenser). A simple capacitor is made from two metal plates (electrodes), which are separated by an insulator such as air, paper or mica (the dielectric).
V. Say if the following statements are true or false. Correct the false
statements.
1. Thereare two different kinds of electricity: AD and ВС.
2. Direct current is received from a battery.
3. AC is used for domestic and industrial purposes.
4. The frequency is the number of cycles per second.
5. Conversion is brought about by means of an insulator.
6. Air is a rather good insulator.
7. High voltage is supplied by a transformer.
8. To decrease voltage a step-down transformer should be used.
9. The function of a capacitor is to transmit electricity to electrical
appliances.
VI. Explain why...
a) two kinds of current exist.
b) electrons change the direction of the flow in AC.
c) a rectifier is necessary.
d) energy is lost on the way from the power plant to the end user.
e) a high voltage and low current are transmitted through the wires.
f) a transformer is used.
g) a transformer is known as a static machine.
h) a step-up transformer permits the input voltage to be increased.
i) acondenser is necessary in domestic appliances.
VII. Give another title to the text. Can you render its contents in 6 simple
sentences?
Activity
I. Create a questionnaire on the topic 'Basic Electricity' and test your
classmates' knowledge.
II. Describe a step-down transformer, its structure, operation and
function. Use the description of a step-up transformer as a model.
III. Solve thecrossword.
Down:
1. to pass power from its source to
the end-user
2. power, current,...
3. to change alternating current into
direct current
4. up-down, closed -...
5. current that flows in one direction
6. their number in the winding
influences voltage
7. the input winding is also called...
winding
8. it alters the direction of charges
9. support wires in the bulb don't do it because they have low
resistance
10. the complete circular path of an electric current
Across:
11.?
Writing
I. Study the picture and describe in writing how electricity is produced and then transmitted to our houses.
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II. Translation Check. Use your dictionary if necessary.
Lightning
To strike the ground lightning must pass two stages. First, a stream of negative electrical charge comes down from the storm cloud in steps. It travels about 160 feet at about fifty-millionths of a second and stops; then moves on another 150 feet and stops - and so on towards the ground. Its function is to create an electrical connection between cloud and ground. The bright flash we know as lightning is the 'return' stroke. It is seen when positive electrical charge travels up from ground to cloud at about a million miles an hour along the path of the least resistance that had already been established.
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Plenty about lightning is still unknown. Cloud and ground are like terminals of a ten-million-volt battery. What charges the battery in the first place? Even the latest scientific achievements do not permit this and other questions to be answered as yet. Electrification of storm clouds remains one of the unsolved mysteries of the weather.
Section B. Solar Energy
Lead-in
I. Discuss the following questions.
a) What role does the Sun play in our life?
b) Some pocket calculators are powered by solar cells, but many use
batteries. What are the advantages of using solar cells? Are there
any disadvantages?
II. Listen to the students' conversation and name the advantages and
disadvantages of solar-powered cars.
Sveta: Alex, just look at this car. It seems to be quite modern.
Alex: Well, it is the latest model of a pollution-free car. Sveta: How interesting! What fuel does it run on?
Alex: It is a solar-powered car - it runs on solar energy. Sveta: Are these cars fast moving?
Alex: Well, they are reported to take part in races and even win them.
Sveta: Oh, really? Do these cars have any disadvantages? As far as I understand, they are sure to stop in cloudy weather and at night when there is little or no sunlight.
Alex: You have a reason here. However, for such cases these cars are provided with solar batteries that accumulate excess energy when there is lots of sunlight and power the car when there is no sunlight.
Sveta: That appears to be a solution to the problem.
Alex: Yes, but these solar batteries are numerous and quite heavy. This makes solar-powered cars rather inefficient at present. There are other questions to tackle.
Sveta: Why do engineers develop these cars if they cause so many problems?
Alex: As the pressure on fossil fuels is likely to increase we have to search for other sources of energy and the solar power is one of them. This energy source is considered to be inexhaustible.
Sveta: I see.
III. Complete the following dialogue.
- This car seems quite modern, doesn't it?
- …
- What source of energy does it use?
- …
-...! Does this car develop high speed?
-Well,...
- I'm afraid such cars are sure to...
- No need to worry. They are supplied with...
- Do they make solar-powered cars efficient?
- Not quite,...
- What is the major advantage...?
IV. Match a line in A with a line in B.
| 1. What is so special about these cars? 2. Are solar-powered cars fast? 3. What are the drawbacks of these cars? |
| a. They are believed to reduce water-heating costs by about 50%. b. They appear to be very expensive. c. Well, they are considered to be pollution free. |
| 4. Why are solar-powered cars created? 5. There are still numerous problems to tackle. 6. Are solar heating systems cost-efficient? |
| d. It seems so. e. Yes, they are reported to win races. f. We are likely to run out of fossil fuels soon and there will be no petrol. petrol. |
Language Practice
Vocabulary
I. Match the words with the similar meaning.
| to convert to solve to absorb to seem to supply usually huge to think |
| to tackle large to turn into to provide to consider to appear to capture normally |
II. Make up all possible word combinations.
| array amount energy resource cars surface heat |
solar
huge
electrical
inexhaustible
to power
metal
to supply
III. Find in В the derivatives from the words in A.
А В
1. to pollute - power, pollution, production, pressure
2. to charge - change, research, discharge, consumer
3. to power - solar-powered, overcharge, operation, piping
4. to exhaust - explanation, expensive, efficiently, inexhaustible
5. to vary - vice versa, variation, weekly, invention
6. new - well-known, consequently, renewable, efficiency
7. complete - competition, completely, tremendous, economical
Grammar: Complex Subject
IV. Match the beginnings of the sentences with their ends. Pay attention to the verbs used with Complex Subject.
| a) generate 100 kilowatts of electricity. b)know the basics of elect- ricity. c) be the unit measure of electricity. d) be inexhaustible. e) produce no pollution. f) be connected. g) come to an end. h) be built in Australia. |
1. Second-year students are expected
to...
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2. The kilowatt-hour is known to...
3. Alternative sources of energy are
considered to...
4. The solar village was reported to...
5. The resources of fossil fuels seem to...
6. Solar-powered cars turned out to...
7. A small windmill is likely to...
8. Electricity and magnetism are sure
to...
V. Open the brackets and use the verbs in the correct form.
1. Some materials (to prove) to produce electricity when they are
exposed to light.
2. The battery (to be likely) to be recharged.
3. Mr. Frolov (to say) to be a good engineer.
4. The collector (to suppose) to be black.
5. That energy source (to seem) to be inexhaustible.
6. A specialist (to expect) to tackle all the technical problems.
7. The solar thermal heating systems (to assume) to be very efficient.
VI. These two sentences have a different structure but the same
meaning. Change the structure of the sentences below so as to keep
their meaning unchanged.
EXAMPLE 1: It is found that the battery is dead. The battery is found to be dead.
1. It is believed that a single PV cell produces approximately 0.5 V.
2. It is likely that the energy crisis will soon begin.
3. It seems that the results of the solar project are very important.
4. It is unlikely that engineers will find a solution to the problem
quickly.
EXAMPLE 2: We expect this method to offer some advantages.
This method is expected to offer some advantages. 1. They consider this housing development to be unique.
The car mechanic believes the solar-powered car to have many advantages.
3. We assume the solar power to be tremendous.
4. He supposes the Sun to run water turbines.
VII. Express the same idea:
a) less categorically.
EXAMPLE: This method gives good results.
This method seem s (appears, is likely, is said) to give good results.
1. This new substance has valuable properties.
2. Solar collectors are very efficient.
3. These batteries are overcharged.
4. The results of the experiment are inaccurate.
b) more categorically.
EXAMPLE: / believe that he will become a good specialist.
He is sure (certain) to become a good specialist.
1. I believe that this problem is of vital importance.
2. We suppose that electric cars will find a wide application.
3. We assume that hot water will be supplied by solar thermal heating
systems.
4. We think these new car batteries are long lasting.
VIII. Restore the original sentences.
1. are known, semiconductors, to be made of, silicon
2. numerous, to offer, solar heaters, seem, advantages
3. efficient, to be, this method, proved, very
4. citizens, the solar village, to inhabit, ordinary, are likely
5. he, to adjust, is believed, the solar batteries, in this car
6. valuable, this new substance, to possess, is sure, properties
IX. Correct mistakes.
1. The engineers was expected to take into account variations in the
intensity of sunlight.
2. Young specialists known to be professionals in their field.
3. The system reports to be pollution-free.
4. The water seem to be heated naturally.
5. The nuclear power stations were turned out to be dangerous.
6. Max is believing to study theoretical mechanics.
7. We are likely exhaust our fossil fuels quickly.
8. This information said to be of utmost importance.
9. Before the race any driver sure to fuel his car.
X. Choose the correct translation for the underlined part of the sentence.
1. The scientists are said to be developing solar thermal heating
systems nowadays.
а) разработали b) разрабатывают
2. They seem to have improved previous results.
а) улучшают b) улучшили
3. An experimental solar heating systems proves to have been built in
this region.
а) строится b) был построен
4. Our total solar energy consumption is estimated to be increasing.
а) увеличивается b) увеличится
5. The research is reported to have been carried out successfully.
а) было проведено b) будет проведено
6. The sufficient amount of electricity is likely to be generated by a
small windmill.
а) вырабатывается b) вырабатывает
XI. Translate the sentences into English using your active vocabulary.
1. Известно, что отдельный фотоэлемент производит 0,5V.
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