IV. Match (21-30) with their definitions (A-L). There are two definitions that you do not need to use.

21. to attract A. rate of recurrence
22. to search B. to exert a force on a body that tends to cause an approach
23. to cause C. easily recognized
24. power D. to link or be linked together
25. invisible E. to examine something closely
26. familiar F. to change into another physical state
27. separate G. concealed from sight
28. to connect H most recent
29. current I. considered independently
30. to convert J. a particular form of energy
    K. to be the reason for
    L. to make or become greater in size

Supplementary Tasks :

I. For statements (1-10) choose the best alternative (A, B or C) to replace the expressions in italics:

1.Although electricity was known to the ancient Greeks … (line 1)

A. recent B. novel C. old

2.… objects "charged" with electricity either attracted or … (line 3)

A. pulled B. dragged C. trailed

3.Scientists soon began to search for a connection … (line 6)

A. account B. look C. hunt

4.… they can attract or repel other objects. (line 9)

A. drive back B. push away C. turn down

5.… invisible forces of magnetism had puzzled people … (line 12)

A. baffled B. clarified C. messed

6.… experimenters were familiar with ... (line 14)

A. acknowledged B. recognized C. acquainted

7.… causing the attractions and repulsions people had observed. (line 17)

A. understood B. realized C. noticed

8.... two coils were not actually connected to each other … (line 21)

A. attached B. united C. joined

9.… they could be converted one to the other. (line 27)

A. transformed B. modified C. reconstructed

10.The discoveries of electromagnetism were very important ... (line 30)

A. consequent B. essential C. pompous

II. Determine the key message of the text. Choose the best alternative (A, B, C, D or E):

A. Electricity and magnetism are two most important notions in Physics since ancient times.

B. Electromagnetism is believed to be one of the main branches of Physics.

C. The study of electricity and magnetism has become important since the sixteenth century.

D. Many discoveries were held to understand the interrelation between electricity and magnetism.

E. Energy transformation suggested scientists one of the main Laws in Physics.

TEXT 3

ELECTROMAGNETISM

                    (1)Although conceived as distinct phenomena until the 19th century, electricity and magnetism are now known to be components of the unified field of electromagnetism. Particles with electric charge interact by an electric force, while charged particles in motion produce and respond to magnetic forces as well. (2) Many subatomic particles, including the electrically charged electron and proton and the electrically neutral neutron, behave like elementary magnets. On the other hand, in spite of systematic searches undertaken, no magnetic monopoles, which would be the magnetic analogues of electric charges, have ever been found. (3)The field concept plays a central role in the classical formulation of electromagnetism, as well as in many other areas of classical and contemporary physics. Einstein’s gravitational field, for example, replaces Newton’s concept of gravitational action at a distance. The field describing the electric force between a pair of charged particles works in the following manner: each particle creates an electric field in the space surrounding it, and so also at the position occupied by the other particle; each particle responds to the force exerted upon it by the electric field at its own position. (4)Classical electromagnetism is summarized by the laws of action of electric and magnetic fields upon electric charges and upon magnets and by four remarkable equations formulated in the latter part of the 19th century by the Scottish physicist James Clerk Maxwell. The latter equations describe the manner in which electric charges and currents produce electric and magnetic fields, as well as the manner in which changing magnetic fields produce electric fields, and vice versa. (5)From these relations Maxwell inferred the existence of electromagnetic waves – associated electric and magnetic fields in space, detached from the charges that created them, traveling at the speed of light, and endowed with such “mechanical” properties as energy, momentum, and angular momentum. The light to which the human eye is sensitive is but one small segment of an electromagnetic spectrum that extends from long-wavelength radio waves to short-wavelength gamma rays and includes X-rays, microwaves, and infrared (or heat) radiation.