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Дидактичнi розробки для студентiв 4 курсу РТФ.doc
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VIII. Complete the following sentences, using active vocabulary:

1. The radio waves travel in a straight line, but they … 2. Elec­tricity could pass through the air as well as… 3. Radio transmit­ters can also send out… 4. A modern broadcast transmitting station has an…5. Valves inside radio sets oscillate the current from… 6. The valves amplify the very small amount of…7. Radio waves are sent out by…

IX. Match terms with the proper definitions:

1.Signal

a) the increase in signal power in transmission from one point to another under stated conditions

2.Gain

b) the number of periods per unit time

3.Frequency

c) a path along which signal can be sent

4.Channel

d) A visual, audible or other indication used to convey information.

X. Give the definitions to the terms:

Radio broadcasting. Radio frequency. Radio interference. Oscillating current. Signal.

Automatic system.

XI. Which of the following statements are true or false? If the statement is wrong, correct it:

1. The men realized that elec­tricity could not pass through the air as well as along a wire. 2. Bell constructed a coherer detector for the study of lightning discharges. 3. Long waves are reflected by the higher ceiling, called the "Appleton layer". 4. Radio transmit­ters can also send out ultra-short waves. 5. Sound waves pass through both layers in the sky but are useful for communicat­ing with spaceships and can even be used to send sound to very short distances when they are reflected from satellites in space. 6. The valves are used to keep the electric circuits oscillating. 7. Radio waves are sent out by direct current. 8. Valves inside your radio set change direct current into alternating current. 9. The valves disseminate the very small amount of electrical energy received from the transmitter.

XII. Translate the following sentences paying attention to the word "broadcast". State what part of speech this word belongs to:

1. The station is broadcasting on ultra-short waves. 2. Men wanted to broadcast the sound of voices and music by wire­less. 3. A modern broadcast transmitting station has an aerial for transmitting sound waves. 4. You may "tune in" to the desired broadcast. 5. Brentwood broadcasting station is one of the largest receiving stations in England. 6. Nowadays broadcasting is spreading fast. 7. Direct-broadcast systems have been constructed. 8. Kyiv broadcasts over four radio programs.

XIII. Answer the following questions:

1. Why messages were sometimes sent to the wrong person? 2. What happens to ra­dio waves when they go into the sky? 3. What is the aim of the “Heaviside layer”? 4. What is the aim of the “Appleton layer”? 5. What waves can pass through both layers? 6. How do satellites in space help us to broadcast? 7. What decides the wave-length? 8. What are the main uses of the valves inside the radio set? 9. Why was constructed the first coherer detector? 10. What makes the centre of the loud speaker vibrate?