Radiophysics. Халюшева Г.Р. - 46 стр.

the two ends of the wire are maintained at a difference of potential, the electric current will flow through a conductor. 4.
What would happen if a freely suspended needle were brought near a conductor carrying a current? In this case the needle
would tend to place itself at right angles to the conductor. 5. It has been calculated that if a giant Atlantic liner could be
constructed of light weight alloys, it would require engines of only 100,000 horse power instead of about 160,000 horse
power to maintain the same speed. 6. Had there been no Earth's gravitation the artificial satellites would nave moved
through airless space in a straight line at a uniform speed. 7. If the satellite's speed were much less than the necessary one, it
might drop and enter the denser layers of the atmoshere. 8. It would have been impossible to launch space satellites and
space rockets provided we had not had the necessary polymeric materials and synthetic fuels. 9. If the Earth were a small
ball, 3 sentimetres in diameter, the Sun would be a globe (ball) 274 cm in diameter. 10. Unless the temperature rises, the
speed of the motion of the molecules will not increase. 11. Were the temperature increased, the velocity of the molecular
motion would also be increased. 12. If you were asked: "How can electric charges be made to flow and what factors
influence their flow?" what would you answer?

            11.3.7     Reproduce the text "What is an electric current"

            11.3.8     Read and translate the text:


         There exist several methods of producing electricity for practical purposes:
       1. Chemical, as represented by the various types of batteries, where producing
electricity takes place due to purely chemical actions.
        2. Electromagnetic, forming the basis of operation of generators in which electricity is produced by conductors
moving through a magnetic field. This is the method utilized in practice for generators of various sizes.
        3. Thermo–electric, in which the heating of the junction between two different metals leads to producing a very
small voltage which may be used for measuring temperature and as a source of power.
        4. Piezo–electric, in which a very small voltage is produced across certain surfaces of a crystal by applying
mechanical pressure.
        5. Electronic, characterized by the flow of electrons through vacuum – or gas–filled tubes.
        In general the purpose determines the nature of the method used to generate energy.

         11.3.9 Do you know...

           ...that M.V.Lomonosov (1711–1765) was the first in Russia to make experiments with atmospheric electricity and
to equip a laboratory for investigating electrical phenomena?
           ...that V.V.Petrov (1761–1834) discovered the electric arc and indicated the possibilities of its utilization as a
source of heat and light?
           ...that P.N.Yablochkov (1847–1894) invented the "Russian candle" (known abroad as "Russian light") which was
the first source of electric light?
           ...that A.N.Lodygin (1847–1923) is the inventor of the incandescent lamp, the most common source of the electric
lamp?
           ...that it was A.S.Popov (1859–1906) who invented the radio in 1895? His work laid the foundation for further
inventions and improvements in the field of radiotelegraphy, broadcasting, television, radiolocation and so on.