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THE NATURE OF ELECTRICITYPractical electricity is produced by small atomic particles known as elec-trons. It is the movement of these particles which produce the effects of heatand light.The pressure that forces these atomic particles to move, the effects theyencounter opposition and how these forces are controlled are some of the prin-ciples of electricity.Accepted atomic theory states that all matter is electrical in structure. Anyobject is largely composed of a combination of positive and negative particlesof electricity. Electric current will pass through a wire, a body, or along astream of water. It can be established in some substances more readily than inothers, that all matter is composed of electric particles despite some basic dif-ferences in materials. The science of electricity then must begin with a study ofthe structure of matter.Matter is defined as any substance which has mass (or weight) and occupiesspace. This definition should be broad enough to cover all physical objects in theuniverse. Wood, water, iron, and paper are some examples of matter. Energy isclosely related to, but not to be confused with, matter. Energy does not havemass, and it does not occupy space. Heat and light are examples of energy.The smallest particle of matter which can be recognized as an originalsubstance was thought to be a unit called the atom. Recently scientists havefound particles even smaller than atoms, but our theories are still based on theatom. The atom consists of a nucleus and a cloud of electrons. It is generallyagreed that the electrons are small particles of electricity, which are negative innature. These particles orbit the nucleus in much the same fashion that planetsorbit a sun.II. Guess the meaning of the following international words:Electricity, electron, effect, structure, combination, material, mass, energy,atom, orbitIII. 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) ядроIV. 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) struc-ture of matter; 8) occupy space; 9) physical objects; 10) a cloud of electrons;11) in the same fashion.V. 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 …VI. Answer the questions:1) What are the principles of electricity? 2) What must the science ofelectricity begin with? 3) Are there any differences between energy and mat-ter? What are they? 4) What is recognized as an original substance now?VII. Topics for discussion:1. The nature of electricity;2. The nature of matter;3. Contents of atomic theory.UNIT 2I. Read the textELECTRIC CURRENTThe electric current is a quantity of electrons flowing in a circuit per sec-ond of time. The unit of measure for current is ampere. If one coulomb passesa point in a circuit per second then the current strength is 1 ampere. The sym-bol for current is I.The current which flows along wires consists of moving electrons. Theelectrons move along the circuit because the e .m. f. drives them. The currentis directly proportional to the e. m. f.In addition to traveling through solids, however, the electric current canflow 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 withoutany change to themselves. Others, called electrolytes, are found to changegreatly when the current passes through them.When the electrons flow in one direction only, the current is known to bed. c., that is, direct current. The simplest source of power for the direct currentis 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 considera-tion flows first in one direction and then in the opposite one. The a. c. used forpower 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 voltagecan be changed into an almost similar amount of power at high voltage and viceversa. Hence, on the one hand alternating voltage is increased when it is neces-sary for long-distance transmission and, on the other hand, one can decrease it tomeet industrial requirements as well as to operate various devices at home.Although there are numerous cases when d. c. is required, at least 90 percent of electrical energy to be generated at present is a. c. In fact, it finds wideapplication for lighting, heating, industrial, and some other purposes.II. Guess the meaning of the following international words:electric, ampere, symbol, proportional, industrial, metal, electrolyte, bat-tery, generate.III. Give the English equivalents for the words and word combinations below:a. 1) течь, протекать; 2) цепь, схема; 3) единица измерения; 4) про-вод; 5) электродвижущая сила; 6) твердое тело; 7) жидкость; 8) прово-дить (ток); 9) источник энергии; 10) постоянный ток; 11) переменныйток; 12) напряжение.IV. Give Russian equivalents for the following:b. 1) to meet industrial requirements; 2) melted metals; 3) to push in thesame direction; 4) negatively (positively) charged terminal; 5) power and light-ning purposes; 6) long-distance transmission; 7) to operate devices; 8) to findwide application.V. 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 withwhich voltage can be changed.VI. Fill in the blanks, using the words from the box:direct current, solids, conduct, electric current, liquids, voltage,alternating of moving electrons flowing in a circuit is the a) _______ .A quantity current.The current can flow through b) ________ and c) ________ . Some liquidsd) _______ current without any change to themselves. When the electronsflow in one direction only, the current is known to be e) _______ . The currentflowing first in one direction and then in the opposite one is f) _______ . Suchadvantage of alternating current as alternating g) _______ finds wide industrialand household application.VII. State the questions to the underlined words:1. Melted metals conduct current without any change to themselves.2. Alternating voltage can be changed to operate various devices at home.3. A battery pushes the electrons in the same direction.4. The alternating current is used for power and lightning purposes.
5. Alternating current accounts for 90 per cent of electrical energy gener-ated now.VIII. Say some sentences about the types of electric current and its propertiesUNIT 3I. Read the textEFFECTS PRODUCED BY A CURRENTThe current flow is detected and measured by any of the effects that itproduces. There are three important effects accompanying the motion of elec-tric charges: the heating, the magnetic, and chemical effects, the latter is mani-fested under special conditions.The production of heat is perhaps the most familiar among the principaleffects of an electric current. The heating effect of the current is found to occurin the electric circuit itself. It is detected owing to an increase in the tempera-ture of the circuit. This effect represents a continual transformation of electricenergy into heat. For instance, the current which flows through the filament ofan incandescent lamp heats that filament to a high temperature.The heat produced per second depends both upon the resistance of the con-ductor and upon the amount of current carried through it. The thinner the wire is,the greater the developed heat is. On the contrary, the larger the wire is, the morenegligible the heat produced is. Heat is greatly desirable at times but at othertimes it represents a waste of useful energy. It is this waste that is generallycalled "heat loss" for it serves no useful purposes and decreases efficiency.The heat developed in the electric circuit is of great practical importancefor heating, lighting and other purposes. Owing to it people are provided with alarge number of appliances, such as: electric lamps that light our homes, streetsand factories, electrical heaters that are widely used to meet industrial re-quirements, and a hundred and one other necessary and irreplaceable thingswhich have been serving mankind for so many years.The electric current can manifest itself in some other way. It is the motionof the electric charges that produces the magnetic forces. A conductor of anykind carrying an electric current, a magnetic field is set up about that conductor.This effect exists always whenever an electric current flows, although in manycases it is so weak that one neglects it in dealing with the circuit. An electriccharge at rest does not manifest any magnetic effect. The use of such a machineas the electric motor has become possible owing to the electromagnetic effect.The last effect to be considered is the chemical one. The chemical effectis known to occur when an electric current flows through a liquid. Thanks to ita metal can be transferred from one part of the liquid to another. It may also ef-fect chemical changes in the part of the circuit comprising the liquid and thetwo electrodes which are found in this liquid. Any of the above mentioned ef-fects may be used for detecting and measuring current.II. Give the English equivalents for the following words:1. выявлять, обнаруживать; 6. лампа накаливания;2. измерять; 7. прибор;3. заряд; 8. потеря энергии;4. нить накала; 9. освещать;5. тепловой эффект; 10. обнаруживаться, проявляться.III. Guess the meaning of the following international words:transformation, temperature, chemical, magnetic, special, practical, mo-tor, electrode.IV. Insert words and expressions:1. The current flow is (выявляется и измеряется) by any of the effectsthat it produces.2. There are three important effects accompanying the motion of (электри-ческие заряды).3. The current which flows through the (нить накала лампы накаливания)heats that filament to a high temperature.4. Heat represents (потерю полезной энергии) at times.5. Electric lamps (освещать) our homes, streets and factories.6. The electric current can (проявлять) magnetic effect.V. Choose the correct translation:The heating effect of the current is found to occur in the electric circuit itself.
1. Установлено, что тепловой эффект электрического тока обнару-живается в самой электрической цепи.2. Тепловой эффект электрического тока может появляться в самойэлектрической цепи.3. Установлено, что тепловой эффект электрического тока долженобнаруживаться в самой электрической цепи.Когда в любом проводнике появляется электрический ток, вокругнего возникает магнитное поле.1. A conductor of any kind carrying an electric current, a magnetic fieldwas set up about that conductor.2. A conductor of any kind have been carrying an electric current, amagnetic field is set up about that conductor.3. A conductor of any kind carrying an electric current, a magnetic fieldis set up about that conductor.Последний эффект, который необходимо рассмотреть – химиче-ский эффект.1. The last effect is considered to be the chemical one.2. The last effect to be considered is the chemical one.3. The last effect would be considered the chemical one.Известно, что химический эффект возникает, когда электриче-ский ток проходит через жидкость.1. The chemical effect is known to occur when an electric current flowsthrough a liquid.2. The chemical effect is famous to occur when an electric current flowsthrough a liquid.3. The chemical effect may be known to occur when an electric currentflows through a liquid.Именно движение электрических зарядов порождает магнитныесилы.1. The motion of the electric charges produces the magnetic forces.2. It is the motion of the electric charges that produces the magnetic forces.3. The motion of the electric charges is certain to produce the magnetic forces.VI. Answer the questions:1. What effects does the current flow produce?2. How is the heating effect detected?3. What does the heat produced depend upon?4. What is called “heat loss”?5. How is the magnetic effect set up?6. What is the main condition of the magnetic effect existence?7. When does the chemical effect occur?VII. Fill in the chart:Electric current effect Practical application1. heating effect …..2. ….. use of electric motor3. chemical effect …..VIII. Speak about the principal effects of an electric current, using thetext and chart aboveUNIT 4I. Read the textElectric CircuitsThe concepts of electric charge and potential are very important in the studyof electric currents. When an extended conductor has different potentials at itsends, the free electrons of the conductor itself are caused to drift from one end tothe other. The potential difference must be maintained by some electric sourcesuch as electrostatic generator or a battery or a direct current generator. The wire
and the electric source together form an electric circuit, the electrons are driftingaround it as long as the conducting path is maintained.There are various kinds of electric circuits such as: open circuits, closedcircuits, series circuits, parallel circuits and short circuits.To understand the difference between the following circuit connections isnot difficult at all. If the circuit is broken or «opened» anywhere, the current isknown to stop everywhere. The circuit is broken when an electric device isswitched off. The path along which the electrons travel must be complete oth-erwise no electric power can be supplied from the source to the load. Thus thecircuit is “closed” when an electric device is switched on.When electrical devices are connected so that the current flows from onedevice to another, they are said «to be connected in series». Under such condi-tions the current flow is the same in all parts of the circuit as there is only asingle path along which it may flow. The electrical bell circuit is considered tobe a typical example of a series circuit. The “parallel” circuit provides two ormore paths for the passage of current. The circuit is divided in such a way thatpart of the current flows through one path and part through another. The lampsin the houses are generally connected in parallel.The “short” circuit is produced when the current can return to the sourceof supply without control. The short circuits often result from cable fault orwire fault. Under certain conditions the short circuit may cause fire because thecurrent flows where it was not supposed to flow. If the current flow is too greata fuse is used as a safety device to stop the current flow.II. Guess the meaning of the following international words:concept, potential, electrostatic generator, aluminum, parallel, typical,control.III. Give the English equivalents for the following words and word combi-nations:1) электрические цепи, 2) электрический заряд, 3) проводник, 4) со-противление, 5) движение электронов, 6) изолятор, 7) короткое замыка-ние, 8) энергия.IV. Say whether these sentences are true or false:1. When an extended conductor has the same potential at its ends, freeelectrons are drifting from one end to another.2. The wire and the electric source together form an electric circuit.3. A path of any material will allow current to exist.4. Silver, copper and gold oppose very strongly.5. The slighter the opposition is, the better the insulator is.6. There is only one type of electric circuit.7. We close the circuit when we switch on our electric device.V. Complete the sentences using the text:1. The potential difference must be maintained by …2. Materials that offer slight opposition are called …3. The best insulators are …4. There are various kinds of electric circuits such as …5. We “open” the circuit when …6. We “close” the circuit when …7. The “short” circuit is produced when …8. A fuse is …VI. Answer the questions:
some most important effects to meet industrial requirements.Some liquids, such as melted metals for example, conduct current withoutany change to themselves. Others, called electrolytes, are found to changegreatly when the current passes through them.When the electrons flow in one direction only, the current is known to bed. c., that is, direct current. The simplest source of power for the direct currentis 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 considera-tion flows first in one direction and then in the opposite one. The a. c. used forpower 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 voltagecan be changed into an almost similar amount of power at high voltage and viceversa. Hence, on the one hand alternating voltage is increased when it is neces-sary for long-distance transmission and, on the other hand, one can decrease it tomeet industrial requirements as well as to operate various devices at home.Although there are numerous cases when d. c. is required, at least 90 percent of electrical energy to be generated at present is a. c. In fact, it finds wideapplication for lighting, heating, industrial, and some other purposes.II. Guess the meaning of the following international words:electric, ampere, symbol, proportional, industrial, metal, electrolyte, bat-tery, generate.III. Give the English equivalents for the words and word combinations below:a. 1) течь, протекать; 2) цепь, схема; 3) единица измерения; 4) про-вод; 5) электродвижущая сила; 6) твердое тело; 7) жидкость; 8) прово-дить (ток); 9) источник энергии; 10) постоянный ток; 11) переменныйток; 12) напряжение.IV. Give Russian equivalents for the following:b. 1) to meet industrial requirements; 2) melted metals; 3) to push in thesame direction; 4) negatively (positively) charged terminal; 5) power and light-ning purposes; 6) long-distance transmission; 7) to operate devices; 8) to findwide application.V. 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 withwhich voltage can be changed.VI. Fill in the blanks, using the words from the box:direct current, solids, conduct, electric current, liquids, voltage,alternating of moving electrons flowing in a circuit is the a) _______ .A quantity current.The current can flow through b) ________ and c) ________ . Some liquidsd) _______ current without any change to themselves. When the electronsflow in one direction only, the current is known to be e) _______ . The currentflowing first in one direction and then in the opposite one is f) _______ . Suchadvantage of alternating current as alternating g) _______ finds wide industrialand household application.VII. State the questions to the underlined words:1. Melted metals conduct current without any change to themselves.2. Alternating voltage can be changed to operate various devices at home.3. A battery pushes the electrons in the same direction.4. The alternating current is used for power and lightning purposes.
5. Alternating current accounts for 90 per cent of electrical energy gener-ated now.VIII. Say some sentences about the types of electric current and its propertiesUNIT 3I. Read the textEFFECTS PRODUCED BY A CURRENTThe current flow is detected and measured by any of the effects that itproduces. There are three important effects accompanying the motion of elec-tric charges: the heating, the magnetic, and chemical effects, the latter is mani-fested under special conditions.The production of heat is perhaps the most familiar among the principaleffects of an electric current. The heating effect of the current is found to occurin the electric circuit itself. It is detected owing to an increase in the tempera-ture of the circuit. This effect represents a continual transformation of electricenergy into heat. For instance, the current which flows through the filament ofan incandescent lamp heats that filament to a high temperature.The heat produced per second depends both upon the resistance of the con-ductor and upon the amount of current carried through it. The thinner the wire is,the greater the developed heat is. On the contrary, the larger the wire is, the morenegligible the heat produced is. Heat is greatly desirable at times but at othertimes it represents a waste of useful energy. It is this waste that is generallycalled "heat loss" for it serves no useful purposes and decreases efficiency.The heat developed in the electric circuit is of great practical importancefor heating, lighting and other purposes. Owing to it people are provided with alarge number of appliances, such as: electric lamps that light our homes, streetsand factories, electrical heaters that are widely used to meet industrial re-quirements, and a hundred and one other necessary and irreplaceable thingswhich have been serving mankind for so many years.The electric current can manifest itself in some other way. It is the motionof the electric charges that produces the magnetic forces. A conductor of anykind carrying an electric current, a magnetic field is set up about that conductor.This effect exists always whenever an electric current flows, although in manycases it is so weak that one neglects it in dealing with the circuit. An electriccharge at rest does not manifest any magnetic effect. The use of such a machineas the electric motor has become possible owing to the electromagnetic effect.The last effect to be considered is the chemical one. The chemical effectis known to occur when an electric current flows through a liquid. Thanks to ita metal can be transferred from one part of the liquid to another. It may also ef-fect chemical changes in the part of the circuit comprising the liquid and thetwo electrodes which are found in this liquid. Any of the above mentioned ef-fects may be used for detecting and measuring current.II. Give the English equivalents for the following words:1. выявлять, обнаруживать; 6. лампа накаливания;2. измерять; 7. прибор;3. заряд; 8. потеря энергии;4. нить накала; 9. освещать;5. тепловой эффект; 10. обнаруживаться, проявляться.III. Guess the meaning of the following international words:transformation, temperature, chemical, magnetic, special, practical, mo-tor, electrode.IV. Insert words and expressions:1. The current flow is (выявляется и измеряется) by any of the effectsthat it produces.2. There are three important effects accompanying the motion of (электри-ческие заряды).3. The current which flows through the (нить накала лампы накаливания)heats that filament to a high temperature.4. Heat represents (потерю полезной энергии) at times.5. Electric lamps (освещать) our homes, streets and factories.6. The electric current can (проявлять) magnetic effect.V. Choose the correct translation:The heating effect of the current is found to occur in the electric circuit itself.
1. Установлено, что тепловой эффект электрического тока обнару-живается в самой электрической цепи.2. Тепловой эффект электрического тока может появляться в самойэлектрической цепи.3. Установлено, что тепловой эффект электрического тока долженобнаруживаться в самой электрической цепи.Когда в любом проводнике появляется электрический ток, вокругнего возникает магнитное поле.1. A conductor of any kind carrying an electric current, a magnetic fieldwas set up about that conductor.2. A conductor of any kind have been carrying an electric current, amagnetic field is set up about that conductor.3. A conductor of any kind carrying an electric current, a magnetic fieldis set up about that conductor.Последний эффект, который необходимо рассмотреть – химиче-ский эффект.1. The last effect is considered to be the chemical one.2. The last effect to be considered is the chemical one.3. The last effect would be considered the chemical one.Известно, что химический эффект возникает, когда электриче-ский ток проходит через жидкость.1. The chemical effect is known to occur when an electric current flowsthrough a liquid.2. The chemical effect is famous to occur when an electric current flowsthrough a liquid.3. The chemical effect may be known to occur when an electric currentflows through a liquid.Именно движение электрических зарядов порождает магнитныесилы.1. The motion of the electric charges produces the magnetic forces.2. It is the motion of the electric charges that produces the magnetic forces.3. The motion of the electric charges is certain to produce the magnetic forces.VI. Answer the questions:1. What effects does the current flow produce?2. How is the heating effect detected?3. What does the heat produced depend upon?4. What is called “heat loss”?5. How is the magnetic effect set up?6. What is the main condition of the magnetic effect existence?7. When does the chemical effect occur?VII. Fill in the chart:Electric current effect Practical application1. heating effect …..2. ….. use of electric motor3. chemical effect …..VIII. Speak about the principal effects of an electric current, using thetext and chart aboveUNIT 4I. Read the textElectric CircuitsThe concepts of electric charge and potential are very important in the studyof electric currents. When an extended conductor has different potentials at itsends, the free electrons of the conductor itself are caused to drift from one end tothe other. The potential difference must be maintained by some electric sourcesuch as electrostatic generator or a battery or a direct current generator. The wire
and the electric source together form an electric circuit, the electrons are driftingaround it as long as the conducting path is maintained.There are various kinds of electric circuits such as: open circuits, closedcircuits, series circuits, parallel circuits and short circuits.To understand the difference between the following circuit connections isnot difficult at all. If the circuit is broken or «opened» anywhere, the current isknown to stop everywhere. The circuit is broken when an electric device isswitched off. The path along which the electrons travel must be complete oth-erwise no electric power can be supplied from the source to the load. Thus thecircuit is “closed” when an electric device is switched on.When electrical devices are connected so that the current flows from onedevice to another, they are said «to be connected in series». Under such condi-tions the current flow is the same in all parts of the circuit as there is only asingle path along which it may flow. The electrical bell circuit is considered tobe a typical example of a series circuit. The “parallel” circuit provides two ormore paths for the passage of current. The circuit is divided in such a way thatpart of the current flows through one path and part through another. The lampsin the houses are generally connected in parallel.The “short” circuit is produced when the current can return to the sourceof supply without control. The short circuits often result from cable fault orwire fault. Under certain conditions the short circuit may cause fire because thecurrent flows where it was not supposed to flow. If the current flow is too greata fuse is used as a safety device to stop the current flow.II. Guess the meaning of the following international words:concept, potential, electrostatic generator, aluminum, parallel, typical,control.III. Give the English equivalents for the following words and word combi-nations:1) электрические цепи, 2) электрический заряд, 3) проводник, 4) со-противление, 5) движение электронов, 6) изолятор, 7) короткое замыка-ние, 8) энергия.IV. Say whether these sentences are true or false:1. When an extended conductor has the same potential at its ends, freeelectrons are drifting from one end to another.2. The wire and the electric source together form an electric circuit.3. A path of any material will allow current to exist.4. Silver, copper and gold oppose very strongly.5. The slighter the opposition is, the better the insulator is.6. There is only one type of electric circuit.7. We close the circuit when we switch on our electric device.V. Complete the sentences using the text:1. The potential difference must be maintained by …2. Materials that offer slight opposition are called …3. The best insulators are …4. There are various kinds of electric circuits such as …5. We “open” the circuit when …6. We “close” the circuit when …7. The “short” circuit is produced when …8. A fuse is …VI. Answer the questions: