Задания для дифференцированного зачета по специальности «Техническая эксплуатация и обслуживание электрического и электромеханического оборудования»
Вариант 1
Read the text
THE NATURE OF ELECTRICITY
Practical electricity is produced by small atomic particles known as electrons. It is the movement of these particles which produce the effects of heat and light.
The pressure that forces these atomic particles to move, the effects they encounter opposition and how these forces are controlled are some of the principles of electricity.
Accepted atomic theory states that all matter is electrical in structure. Any object is largely composed of a combination of positive and negative particles of electricity. Electric current will pass through a wire, a body, or along a stream of water. It can be established in some substances more readily than in others, that all matter is composed of electric particles despite some basic differences in materials. The science of electricity then must begin with a study of the structure of matter.
Matter is defined as any substance which has mass (or weight) and occupies space. This definition should be broad enough to cover all physical objects in the universe. Wood, water, iron, and paper are some examples of matter. Energy is closely related to, but not to be confused with, matter. Energy does not have mass, and it does not occupy space. Heat and light are examples of energy.
The smallest particle of matter which can be recognized as an original substance was thought to be a unit called the atom. Recently scientists have found particles even smaller than atoms, but our theories are still based on the atom. The atom consists of a nucleus and a cloud of electrons. It is generally agreed that the electrons are small particles of electricity, which are negative in nature. These particles orbit the nucleus in much the same fashion that planets orbit a sun.
2. Guess the meaning of the following international words:
Electricity, electron, effect, structure, combination, material, mass, energy, atom, orbit
3. Give the English equivalents for the words below:
1) производить; 2) частица; 3) тепло и свет; 4) напряжение; 5) сила; 6) вещество; 7) положительный; 8) отрицательный; 9) электрический ток; 10) вес; 11) ядро
4. Translate into Russian the words and expressions from the text:
1) atomic particle; 2) effects of heat and light; 3) encounter opposition; 4) principles of electricity; 5) composed (of); 6) pass through a wire; 7) structure of matter; 8) occupy space; 9) physical objects; 10) a cloud of electrons; 11) in the same fashion.
5. Complete the sentences using the text:
1. Electricity is produced by …
2. The effects of heat and light are produced by …
3. According to the accepted atomic theory all matter is …
4. Any object is composed of …
5. Matter is defined as …
6. Energy must not be confused with …
7. The atom consists of …
8. The smallest particle of matter is …
9. Most theories are based on …
10. Electrons are …
Вариант 2
№ 1 Read the text
ELECTRIC CURRENT
The electric current is a quantity of electrons flowing in a circuit per second of time. The unit of measure for current is ampere. If one coulomb passes a point in a circuit per second then the current strength is 1 ampere. The symbol for current is I.
The current which flows along wires consists of moving electrons. The electrons move along the circuit because the e .m. f. drives them. The current is directly proportional to the e. m. f.
In addition to traveling through solids, however, the electric current can flow through liquids as well and even through gases. In both cases it produces some most important effects to meet industrial requirements.
Some liquids, such as melted metals for example, conduct current without any change to themselves. Others, called electrolytes, are found to change greatly when the current passes through them.
When the electrons flow in one direction only, the current is known to be d. c., that is, direct current. The simplest source of power for the direct current is a battery, for a battery pushes the electrons in the same direction all the time (i.e., from the negatively charged terminal to the positively charged terminal).
The letters a. c. stand for alternating current. The current under consideration flows first in one direction and then in the opposite one. The a. c. used for power and lighting purposes is assumed to go through 50 cycles in one second. One of the great advantages of a. c. is the ease with which power at low voltage can be changed into an almost similar amount of power at high voltage and vice versa. Hence, on the one hand alternating voltage is increased when it is necessary for long-distance transmission and, on the other hand, one can decrease it to meet industrial requirements as well as to operate various devices at home.
Although there are numerous cases when d. c. is required, at least 90 per cent of electrical energy to be generated at present is a. c. In fact, it finds wide application for lighting, heating, industrial, and some other purposes.
2. Guess the meaning of the following international words:
electric, ampere, symbol, proportional, industrial, metal, electrolyte, battery, generate.
3. Give the English equivalents for the words and word combinations below:
1) течь, протекать; 2) цепь, схема; 3) единица измерения; 4) провод; 5) электродвижущая сила; 6) твердое тело; 7) жидкость; 8) проводить (ток); 9) источник энергии; 10) постоянный ток; 11) переменный ток; 12) напряжение.
4. Give Russian equivalents for the following:
1) to meet industrial requirements; 2) melted metals; 3) to push in the same direction; 4) negatively (positively) charged terminal; 5) power and lightning purposes; 6) long-distance transmission; 7) to operate devices; 8) to find wide application.
5. Say whether these sentences are true or false:
1. The symbol for current is I.
2. The electric current can flow only through liquids.
3. The current can be of two types: direct current and alternating current.
4. The alternating current flows in one direction.
5. A battery is the simplest source of power for the direct current.
6. Direct current finds wider application than alternating current.
7. Electrolytes don’t change greatly when current passes through them.
8. One of the great advantages of alternating current is the ease with which voltage can be changed.
Эталоны ответов
1 вариант 2 вариант
2. Guess the meaning of the following international words:
Электричество
Электрон
Эффект
Структура
Комбинация
Материал
Масса
Энергия
Атом
Орбита
2. Guess the meaning of the following international words:
Электрический
Ампера
Символ
Пропорциональный
Промышленный
Металл
Электролит
Аккумулятор
Генерировать
3. Give the English equivalents for the words below:
1) to produce;
2) the particle;
3) heat and light;
4) voltage;
5) current;
6) substance;
7) positive;
8) negative;
9) electric current;
10) weight;
11) core
3. Give the English equivalents for the words and word combinations below:
1) the leak to proceed;
2) chain, scheme;
3) unit of measure;
4) wire;
5) electromotive force;
6) the solid body;
7) the liquid;
8) To (current);
9) the energy source;
10) direct current;
11) AC current;
12) voltage
4. Translate into Russian the words and expressions from the text:
1) атомная частица; 2) эффекты высокой температуры и света; 3) оппозиция столкновения; 4) принципы электричества; 5) составленный (из); 6) проходят через провод; 7) структура материи; 8) занимают пространство; 9) физические объекты; 10) облако электронов; 11) таким же образом.
4. Give Russian equivalents for the following:
1) отвечать промышленным требованиям; 2) расплавленные металлы; 3) продвинуться в том же самом направлении; 4) отрицательно (положительно) заряженный терминал; 5)мощности и молнии целей 6) передачи на дальние расстояния; 7) управление устройствами; 8) найти
широкое применение.
5. Complete the sentences using the text:
1. Electricity is produced by by small atomic particles known as electrons
2. The effects of heat and light are produced by the movement of these particles
3. According to the accepted atomic theory all matter is electrical in structure
4. Any object is composed of positive and negative particles of electricity
5. Matter is defined as any substance which has mass (or weight) and occupies space
6. Energy must not be confused with matter
7. The atom consists of a nucleus and a cloud of electrons
8. The smallest particle of matter is the atom
9. Electrons are small particles of electricity
5. Say whether these sentences are true or false:
T- 1. The symbol for current is I.
F - 2. The electric current can flow only through liquids.
T - 3. The current can be of two types: direct current and alternating current.
F- 4. The alternating current flows in one direction.
T - 5. A battery is the simplest source of power for the direct current.
T - 6. Direct current finds wider application than alternating current.
F - 7. Electrolytes don’t change greatly when current passes through them.
T - 8. One of the great advantages of alternating current is the ease with which voltage can be changed.
