III. After-text Exercises:

1. Agree or disagree with the next statements:

1. Radio waves consist of magnetic and electrostatic fields at right angles to each other and also at right angles to the direction of travel.

2. The radio waves produced by alternating current will not vary in intensity with the frequency of the current and will not therefore be alternately positive and negative:

3. The distance occupied by one complete cycle of such an alternating wave is equal to the velocity of the wave divided by the number of cycles that are sent out each second and is called the wave length.

4. The quantity 200 000 000 is the velocity of light in meters per second.

5. The frequency is ordinary expressed in kilocycles or in megacycles.

2. Find the information about:

1) the velocity of radio waves;

2) the form of existence of the electrical energy in the wave;

3) the essential properties of a radio wave;

4) the relation between wave length in meters and frequency in cycles per second;

5) the expression of frequency.

3. Put questions to each other.

4. Summarize the general ideas of the text. Use the following plan:

1. Forms of existence of electrical energy contained in the radio wave.

2. The essential properties of a radio wave.

3. Measuring of the strength of a radio wave.

4. Main characteristics of radio wave travelling.

5. The direction of polarization of the wave.

5. Put the verbs in brackets into the correct form using Passive:

1. This experiment (to insist)________on by our engineers yesterday.

2. Several types of lasers (to develop)_________every year.

3. The apparatus (to check)________at the lab by our engineers next week.

4. Automation (to use widely)________in space research now.

5. While the experiment (to carry out)_________nobody left the lab.

6. Now different types of radio devices (to study)________by a lot of research groups.

7. The apparatus used in our research (to describe)________recently.

8. After a new device (to test)________it was installed in our laboratory.

9. The construction of this television centre (to complete)________by the end of the next year.

10. The information (to base)________on the data received from a computer.

11. A new type of computing equipment (to produce)________at this plant now.

12. This experiment (to carry out)________under low pressure when the engineers decided to change the conditions of the work.

13. lt is well-known fact that the computer must (to take)________ care of.

14. Future engineers (to give)_________practical training at the best laboratories of our institute.

15. This new measuring device (to design)_________by the end of the next year.

16. The engineer (to ask)________to test the apparatus yesterday.

17. A new device for measuring pressure (to design)__________now.

18. Your invention (to speak)________of at the last meeting.

19. The magnetron is a vacuum tube whose current (to influence) _________by a magnetic field.

20. At this time tomorrow a new magnetic gear (to install)________.

21. The new device (to test)________for two hours when the chief engineer came and stopped the experiment.

22. The scientist (to offer)________ new theme for research.

23. Another useful metal is tungsten which (to use widely)________in industry.

24. The engineer was shown a new device which (to construct) _________by the scientists and engineers of their laboratory.

25. A new type of electronic equipment (to give)________much attention to.