I. Find out the words in the dictionary. Write them down and learn

II. Read the text. Use a dictionary, if necessary.

TEXT: «ELECTRONICS»

Electronics is a general term for the production and processing of electric signals (consisting of moving electrons, hence the name electronics) that convey information – for example, the sound reproduction by a radio or record player and the data output of a computer. Electron ics also includes the production and processing of beams of electrons, used in such devices as cathode-ray oscilloscopes, television sets, and electron microscopes. Electric signals. Electric signals are produced by devices that convert the primary information source (which is in the form of another type of energy – sound or light, for instance) into small electric currents. For example, a microphone converts sound into an electric current, and in input unit of a computer converts data. These currents, which constitute a signal, are then transmitted along wires or, after conversion to radio waves, via radio links. On reaching a suitable receiver, they may be electronically manipulated – to reduce distortion in the signal, for instance – and are than amplified so that they can drive an output device, such as a loudspeaker, television set, or computer printer. There are two types of electric signal: analog and digital. Analog signals vary continuously in voltage or current, corresponding to variations in the primary information source; thus the electric signals produced by a microphone are electrical «copies» of the original sound waves. Digital signals are not continuous but consist of numerous bursts of electric current between two voltage levels (one of which may be zero). A computer uses digital signals. They consist of binary codes that represent the numbers, letters, and symbols in the input data and in the various program instructions. In the computer’s central processor, the data codes are subjected to processes of binary arithmetic or are compared with each other to obtain the results required by the program. In modern electronics, electric signals may be processed in two main ways – by passing them trough semiconductor devices (such as transistors) or by converting them into a beam of electrons, as in the formation of a picture by a television set (which also uses semiconductors). Semiconductors. Semiconductors are substances (such as silicon and germanium) whose electrical resistance lies between that of conductors and insulators. They have this intermediate resistance because they have a few free electrons that can drift from atom to atom – unlike conductors, which have many free electrons, and unlike insulators, which have none. The semiconductors used in electronic devices are «doped» to change their electrical properties. Doping involves introducing minute traces of other elements into the semiconductor’s crystal lattice. Silicon and germanium each have four outer electrons per atom; doping them with an element with five outer electrons, such as phosphorus, frees the fifth electron so that the semiconductor has an electron excess. It is then known as an n-type (negative-type), because electrons have a negative charge. Doping with an element that has only three outer electrons, such as boron, produces a crystal lattice with spaces, known as holes, which free electrons readily fill. This type of semiconductor has a lack of free electrons, which is equivalent to an excess of positive charges, and it is therefore known as p-type. If a piece of n-type semiconductor is joined to a piece of p-type, the resulting device is called a p/n junction diode. If the diode is then connected to a battery so that the negative terminal is joined to the n-type semiconductor and the positive terminal to the p-type, current flows through the junction. Transistors. Transistors are arrangements of semiconductor diodes that act as amplifiers. There are two main types: junction and field-effect transistors.

III. Find the sentences that can’t be found in the text.

1. The subject of electronics should, in its broadest sense, embrace all phenomena that are associated with the electron, the fundamental unit of negative electricity.

2. Electronics also includes the production and processing of beams of electrons, used in such devices as cathode-ray oscilloscopes, television sets, and electron microscopes.

3. There are two types of electric signal: analog and digital.

4. Semiconductors are substances (such as silicon and germanium) whose electrical resistance lies between that of conductors and insulators.

5. Semiconductors are materials which lie between conductors and insulators.

6. If a piece of n-type semiconductor is joined to a piece of p-type, the resulting device is called a p/n junction diode.

7. Transistors are arrangements of semiconductor diodes that act as amplifiers.

V. Find Uzbek equivalents to the following expression in the text.

1. the production and processing of electric signals ______________

2. convey information ____________________________________

3. beams of electrons ____________________________________

4. the primary information source ___________________________

5. small electric currents __________________________________

6. are transmitted along wires _____________________________

7. via radio links _______________________________________

8. a suitable receiver ____________________________________

9. may be electronically manipulated ________________________

10. numerous bursts of electric current ______________________

11. binary codes _______________________________________

12. minute traces _______________________________________

13. act as amplifiers ____________________________________

VI. Fill in the missing words.

1. Electronics is a general term for the _____ and _____ of electric signals that convey information.

2. Electric signals are produced by devices that the primary information _____ into small electric _____.

3. Digital signals consist of _____ codes that represent the numbers, letters, and symbols in the input data and in the various program instructions.

4. In modern electronics, electric signals may be processed in two main ways: by passing them through _____ _____ or by converting them into a _____ of _____.

5. Semiconductors are substances whose electrical resistance lies between that of _____ and _____.

6. Doping involves introducing minute traces of other elements into the semiconductor’s _____ _____.

7. Transistors are arrangements of semiconductor diodes that act as _____.

VII. Fill in the preposition, if necessary.

1. Electronics also includes ___ the production and processing ___ beams ___ electrons.

2. Analog signals vary continuously ___ voltage or current, corresponding ___ variations ___ the primary information source.

3. Digital signals are not continuous but consist ___ numerous bursts ___ electric current between two voltage levels.

4. ___ the computer’s central processor, the data codes are subjected ___ process ___ binary arithmetic or are compared ___ each other to obtain the results required ___ the program.

5. If the diode is then connected ___ a battery so that the negative terminal is joined ___ the n-type semiconductor and the positive terminal ___ the p-type, current flows ___ the junction.

VIII. Define whether the sentences are true or false.

1. Electric signals are produced by devices that convert the primary information source into small electric currents

2. Digital signals vary continuously in voltage or currant, corresponding to variations in the primary information source.

3. Analog signals are not continuous but consist of numerous bursts of electric current between two voltage levels.

4. In the computer’s central processor the data codes are subjected to process of binary arithmetic or are compared with each other to obtain the results required by the program.

5. Semiconductors are substances whose electrical resistance lies between that of conductors and insulators.

6. Doping with an element that has only three outer electrons produces a crystal lattice without any spaces.

IX. Practice with someone asking and answering.

1. What is electronics?

2. What are electric signals produced by?

3. How many types of electric signal are there?

4. What signals does a computer use?

5. What do digital signals consist of?

6. In what ways may electric signals be processed in modern electronics?

7. What is semiconductor?

8. What does doping involved?

9. What is a transistor?

10. How many types of transistors do you know?

X. Put questions to the following sentences.

1. Electronics includes the production and processing of beams of electrons. (General)

2. Electric signals are produced by devices that convert the primary information source into small electric currents. (Disjunctive)

3. There are two types of electric signal. (Alternative)

4. The electrical resistance of semiconductors lies between that of conductors and insulators. (Special)

5. The semiconductors used in electronic devises are «doped» to change their electrical properties. (What ...?)

6. Doping with an element that has only three outer electrons produces a crystal lattice with spaces, known as holes. (Disjunctive)

XI. Dictate the following sentences in English to your fellow-students. Check them together.

1. Electronics is a general term for the production and processing of electric signals that convey information.

2. Electric signals are produced by devices that convert the primary information source into small electric currents.

3. Analog signals vary continuously in voltage or current, corresponding to variations in the primary information source.

4. Digital signals are not continuous but consist of numerous bursts of electric current between two voltage levels.

5. Semiconductors are substance whose electrical resistance lies between that of conductors and insulators.

UNIT 21

I. Find out the words in the dictionary. Write them down and learn.

property, to exhibit, to some extent, minute, diamagnetic, para-

magnetic, ferromagnetic, solenoid, to cancel out, overall, to associ-

ate with, atomic dipoles, at random, inducing field, to align, suscep-

tibility, to overwhelm

II. Read the text. Use the dictionary, if necessary.

TEXT: «MAGNETISM»

Magnetism is one of the fundamental properties of matter. All substances – even those such as glass, plastics, and wood, for example – exhibit magnetic properties to some extent, although most materials do so to such a minute degree that they are generally regarded as nonmagnetic. Only the metallic elements iron, nickel, and cobalt, and certain of their alloys (such as steel) are strongly magnetic; such substances are described as being ferromagnetic. In general all materials can be classed as diamagnetic, paramagnetic, or ferromagnetic. Each behaves in a characteristic way when placed inside a current-carrying solenoid (that is, in a uniform magnetic field), depending on the electronic structure of the atoms and the arrangement of the atoms themselves within the material. In a piece of diamagnetic material (such as bismuth or copper), the electrons in each atom are arranged so that their magnetic effects cancel out each other; hence a diamagnetic substance has no overall magnetic field associated with it. If a bar of the material is placed in an inducing field, however, the electron paths are slightly distorted. As a result, the substance becomes very weakly magnetized, but in the opposite direction to that of the inducing field. Hence the susceptibility (the ratio of the induced to the inducing magnetic field) of diamagnetic materials is very small and negative (typically about – 10 -5 ). If a bar of diamagnetic material is freely suspended in a strong uniform magnetic field, it aligns itself across the field. In a paramagnetic material (such as platinum or aluminum) the magnetic effects of the electrons do not cancel completely and each atomacts like a minute, weak bar magnet. Under normal cumstances, these atomic dipoles are oriented at random and there is no overall magnetic effect. Under the influence of an inducing field, however, the dipoles tend to align with the field. As a result, the magnetic field induced in the substance is in the same direction as that of the inducing field, and a freely-suspended bar of paramagnetic material therefore aligns itself with the inducing field. But the dipole alignment is not complete and so the induced magnetism tends to be weak, although it is still strong enough to overwhelm the diamagnetic effect. The susceptibility of paramagnetic substances is small and positive (in the order of +10 -3 ). Many substances are paramagnetic, but very few exhibit the third and most important form of magnetism – ferromagnetism. Ferromagnetic materials, such as iron and cobalt, display paramagnetic behavior, but much more strongly than most paramagnetic substances because many more atomic dipoles align when in an inducing field. Thus ferromagnetic materials have large, positive susceptibilities (often greater that +10 3 ).

III. Find the words with negative meaning and translate them.

Extent, minute, nonmagnetic, ferromagnetic, uncertain, uniform,

typically, useless, unlimited, uncompleted, dipole, paramagnetic, weak-

ness, unimportant, display, susceptibility, unspecified, induce, regard-

less, decode, ratio, useless, atomic, disadvantage.

IV. Find the sentences that can’t be found in the text.

1. Magnetism is one of the fundamental properties of matter.

2. In fact, all magnetic effects are caused by movements of electric

charges.

3. Only the metallic elements are strongly magnetic.

4. An important concept in magnetism is that of the magnetic pole.

5. A magnetic compass points to the earth’s magnetic north pole

rather than the true, geographical North Pole.

6. A diamagnetic substance has no overall magnetic field associat-

ed with it.

7. The dipole alignment in a paramagnetic material is not complete

and the induced magnetism in this case tends to be weak.

8. Magnetite, a form of iron ore, is the principal naturally-occurring ferromagnetic material.

VI. Find Uzbek equivalents to the following expressions in the text.

1. fundamental properties ________________________________

2. to some extent ________________________________________

3. such a minute degree __________________________________

4. are generally regarded as ________________________________

5. a uniform magnetic field _______________________________

6. has no overall magnetic field ____________________________

7. electron paths _______________________________________

8. as a result ___________________________________________

9. the ratio of the induced to the inducing magnetic field __________

10. to cancel completely __________________________________

11. under normal circumstances ____________________________

12. at random __________________________________________

13. to align with the field _________________________________

14. a freely-suspended bar ________________________________

15. to overwhelm the diamagnetic effect ______________________

16. many more atomic dipoles _____________________________

VII. Fill in the missing words.

1. Magnetism is one of the fundamental _______ of matter.

2. All substances exhibit magnetic properties to some _______,

although most materials do so to such a minute _______ that they are

regarded as _______.

3. Materials can be classed as diamagnetic, _______, or ferromagnetic.

4. Each material behaves in a characteristic way when placed _______

a current-carrying _______.

5. In a piece of _______, the electrons in each atom are arranged so

that their magnetic effects cancel out each other.

6. In a _______ material the magnetic effects of the electrons do not

cancel completely and each atom acts like a minute, weak bar _______.

7. Materials which are _______ have large, positive susceptibili-

ties (often greater than +10 3 ).

VIII. Fill in the prepositions, if necessary.

1. All substances exhibit magnetic properties ____ some extent, although most ____ materials do so ____ such a minute degree that they are generally regarded ____ nonmagnetic.

2. Each material behaves ____ a characteristic way when placed inside a current-carrying solenoid, depending ____ the electronic structure ____ the atoms and the arrangement ____ the atoms themselves within the material.

3. In a piece of diamagnetic material such ____ bismuth or copper, the electrons ____ each atom are arranged so that their magnetic effects

cancel ____ each ____ other.

4. If a bar ____ the diamagnetic material is placed ____ an inducing field, the electron paths are slightly distorted ____.

5. ____ normal circumstances, these atomic dipoles are oriented ____ random and there is no overall magnetic effect.

6. Under the influence ____ an inducing field the dipoles tend ____ align ____ the field.

7. Ferromagnetic materials display ____ paramagnetic behaviour, but much more strongly ____ most paramagnetic substances.

IX. Define whether the sentences are true or false.

1. Magnetism is the only fundamental property of matter.

2. Not all substances exhibit magnetic properties.

3. The metallic elements such as iron, cobalt, bismuth are regarded to be ferromagnetic.

4. In general all materials can be classed as paramagnetic or ferromagnetic.

5. Solenoid can be described as a uniform magnetic field.

6. The behavior of a definite material placed inside a current-carrying solenoid depends only on the electronic structure of the atoms within the material.

7. A diamagnetic substance has no overall magnetic field associated with it.

8. The ratio of the induced to the inducing magnetic field is called the susceptibility of a material.

9. Only diamagnetic materials possess negative susceptibilities.

10. The induced magnetism in a paramagnetic material tends to be very strong, much stronger than that in a ferromagnetic material.

X. Practice with someone asking and answering.

1. What is magnetism?

2. Do all substances exhibit magnetic properties?

3. What substances are generally regarded as nonmagnetic ones?

4. What types of magnetism can you name?

5. What influences the behavior of a material when placed inside a current-carrying solenoid?

6. What materials are called diamagnetic?

7. What kind of magnetism can we observe in a paramagnetic material under the influence of an inducing field?

8. What is the most important form of magnetism?

9. How do atomic dipoles in a ferromagnetic material act when in an inducing field?

10. Can you give the examples of diamagnetic and ferromagnetic materials?

11. What can be said about susceptibilities of different materials?

XI. Put questions to the following statements.

1. The electrons in each atom are arranged so that their magnetic effects cancel out each other.

2. Under the influence of an inducing field the dipoles tend to align with the field.

3. Ferromagnetic materials have large, positive susceptibilities.

XII. Dictate the following statements in English to your fellowstudents.

1. Magnetism is one of the fundamental properties of matter.

2. All substances exhibit magnetic properties to some extent.

3. In general all materials can be classed as diamagnetic, paramagnetic, or ferromagnetic.

4. Each behaves in a characteristic way when placed inside a current-carrying solenoid.

5. A diamagnetic substance has no overall magnetic field associated with it.

6. In a paramagnetic material the magnetic effects of the electrons do not cancel completely and each atom acts like a weak magnet.

7. Very few substances exhibit the most important form of magnetism – ferromagnetism.

UNIT 22

I. Find out the words in the dictionary. Write them down and learn.

mutual, pervasive, to take for granted, measurement, product,

to denote, adequate, weak, to apply to, relativity, according to, cur-

vature, rays of light, wave, indirect, to suffice

II. Read the text. Use a dictionary, if necessary.

TEXT: «GRAVITY»

Gravity is a force of the mutual attraction between objects that have mass. Its influence in everyday life is so pervasive that it is taken for granted. The seventeenth-century mathematician and physicist Isaac Newton was the first to formulate the law of gravitation. He expressed it in mathematical terms that could be used in calculations. It was called Newton’s law of universal gravitation. It states that the gravitational force between two objects is directly proportional to the product of the masses of the two objects, and inversely proportional to the square of the distance between them. To make calculations possible, it is necessary to include a constant, G, which is known as the universal constant of gravitation. Experimental measurements have shown that the gravitational constant G has a value of about 6.67 x 10 - №№ N mІkg - І. Physicists characterize the strength of a gravitational field in terms of the acceleration that a body of a certain mass and radius produces on a falling object. It can be found by equating the force of gravity between the body and a mass of 1kg with Newton’s second law of motion, which gives the acceleration produced by a force acting on a particular mass. The result (the acceleration due to gravity, or the gravitational field strength) is denoted by g, which for the Earth has a value of about 9.8 m s - І. Newton’s mathematical description of gravity is adequate for weak gravitational fields. But it fails when applied to large masses confined to small regions in which the force of gravity is very strong. In this case Einstein’s theory of gravitation (the General Theory of Relativity) has to be used. According to Einstein’s General Theory of Relativity, the mutual attraction between objects is the result of the curving of space and time around them. The curvature has observable effects on rays of light that pass close to massive objects, such as the sun or other stars. Studies of these effects indicate that the idea of space-time curvature is valid. Einstein suggested that gravitation is a curved field in the space-time continuum, rather than a force as Sir Isaak Newton had thought. One prediction of the General Theory is the existence of gravitational waves, a phenomenon produced whenever an object is accelerated. But gravitational waves are so weak that they have not yet been detected directly; at present there is only indirect evidence for their existence. In most situations, however, Newton's law suffices for calculating gravitational forces. A commonplace manifestation of the gravitational attraction between massive bodies is the phenomenon of the tides, which results from the unequal attractions of the moon and sun on the water in the oceans of the earth. Note: 6.67x10 -11 – six point six seven multiplied by ten to the minus eleventh.

III. Give adjectives corresponding to the following nouns and translate them.

Gravitation, attraction, mass, influence, calculation, universe, pro-

portion, experiment, value, object, weakness, region, strength, theory, rel-

ativity, mutuality, validity, prediction, existence, evidence, inequality.