Учебные задания по английскому языку для студентов 2 курса специальности «Электроэнергетика и электротехника», 3 семестр

The force with which magnetic poles attract or repel each other depends on the strength of the poles and the distance between them. This relationship is similar to the

Coulomb’s inverse square law for electric charges.

The similarities between electric and magnetic phenomena indicate that electricity and magnetism are related. Electricity produces magnetic effects and magnetism produces electric effects. The relationship between electricity and magnetism is called electromagnetism.

Magnetic Effects of Electricity

It has been noted that an electric field exists around any electric charge. If electric charges are moving, they constitute an electric current. The magnetic effect of electricity is demonstrated by the fact that a magnetic field exists around any electric current. The field can be detected when a magnet is brought close to the currentcarrying conductor.

The magnetic field around an electric current can be thought of as lines of magnetic force that form closed circular loops around the wire that carries the current. The direction of the magnetic field can be determined by a convenient rule called the right-hand rule. To apply this rule, the thumb of the right hand is pointed in the direction in which the current is flowing and the fingers are curled around the wire. The direction of the fingers then indicates the direction of the lines of magnetic force. (The right-hand rule assumes that current flows from positive to negative.)

Motor Effect

As already stated, a magnetic field exists around a wire carrying an electric current, and a magnetic field exists between the two poles of a magnet. If the wire is placed between the poles, the magnetic fields interact to produce a force that tends to push the wire out of the field. This phenomenon, known as the motor effect, is used in electric motors.

VOCABULARY PRACTICE

1. Find English equivalents to the following words and word combinations.

a. составлять;

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b. круговые линии;

c. противоположные полюса;

d. выталкивать проводник (из поля); e. существовать;

f. сходство, сходные характеристики; g. окружать (проводник);

h. явление;

i. магнитный эффект;

j. магнитные силовые линии.

2. Write out the passage using the correct form of the verbs in brackets.

SOLENOIDS

If a wire (1)________(bend) into many continuous loops to form a long spiral coil, then the magnetic lines of force tend (2)______(go) through the center of the coil from one end to the other rather than around the individual loops of wire. Such a coil,

(3)_______(call) a solenoid, (4)________(behave) in the same way as a magnet and

(5)____(be) the basis for all electromagnets. The end from which the lines

(6)______(exit) (7)____(be) the north pole and the end into which the lines

(8)_______(reenter) (9)___(be) the south pole. The polarity of the coil can (10)___________(determine) by (11)________(apply) the left-hand coil rule. If the left hand (12)______(grasp) the coil in such a way that the fingers (13)______(curl) around in the direction of the electron current, then the thumb (14)______(point) in the direction of the north pole.

3. Fill in the correct preposition.

MAGNETISM

Magnetism is an aspect ___ electromagnetism, one ___ the fundamental forces ___

nature. Magnetic forces are produced ___ the motion ___ charged particles such as electrons, indicating the close relationship ___ electricity and magnetism. The

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unifying frame ___ these two forces is called electromagnetic theory. The most familiar evidence ___ magnetism is the attractive or repulsive force observed to act

___ magnetic materials such as iron. More subtle effects ___ magnetism, however, are found ___ all matter. ___ recent times these effects have provided important clues

___ the atomic structure ___ matter.

4. Complete the text using one of the words from the box.

Hans Christian Oersted (1)__________ in 1813 that a (2)____________would be

(3)__________between electricity and (4)_____________. In 1819 he

(5)___________a compass near a current-carrying wire and observed that the compass needle was (6)___________. This (7)___________demonstrated that electric currents produce magnetic fields.

6.Complete each sentence with one of the endings.

a.Compass is an instrument that…

b.Compass enables mariners and navigators…

c.Two fundamental types of compass are used:…

d.In the magnetic compass, directions are obtained by means of…

e.The gyrocompass is…

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f.The magnetic compass…

g.The gyrocompass was…

1.…one or more magnetic needles.

2.…to get from one place to another.

3.…unaffected by the magnetism of the earth.

4.…indicates direction.

5.…developed at the beginning of the 20th century.

6.…originated in ancient China.

7.…the magnetic compass and the gyrocompass.

SPEAKING

Make a presentation on magnetic effects of electricity. Pay special attention to the texts of the module. Use additional information and add your own ideas. WRITING

You are running a firm producing various compasses. Write an advertisement for a specialized magazine introducing new products.

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