Make up situations using the English equivalents of the words given above. 39. Give Russian equivalents to the following word combinations:

39. Give Russian equivalents to the following word combinations:

repulsive forces; stationary structure; particular direction; in order to...; angular acceleration; permanent magnets; familiar shape; resistive energy; induction motor; alternating current; changing magnetic poles; electromagnetic doorbell; to complete a circuit; coil of wire; inside the solenoid; a weak spring; to twist a rotor; to push a carriage; to rotate around the rotor; magnetic environment; to transfer power; to reverse the direction

40. Work in pairs, think of some questions to review the contents of the text and ask each other. Use the word combinations below:

41. Read Text 10D once more. In pairs, discuss the statements below. Say what you think about them and ask your partner if he/she agrees or disagrees with you. Use the following phrases to help you:

1. An electric motor uses only repulsive force between magnetic poles to twist a rotating object (the rotor) around in a circle.

2. An electric current is itself magnetic — it creates a structure in the space around it that exerts forces on any magnetic poles in that space.

3. If current flows around the loop in the direction of the fingers of your right hand, then your thumb points to the north pole that develops at one end of the coil.

4. The magnetic interaction between the stator and the rotor is not repulsive.

5. A fan motor is an induction motor, with an aluminum rotor that spins inside a framework of stationary electromagnets.

6. When you press the button of an electromagnetic doorbell, you complete a circuit that includes a source of electric power.

7. Linear electric motors are not like rotary electric motors — they do not use the forces between magnetic poles to push one object relative to another.

8. To keep the center component or «rotor» of an electric motor spinning, the magnetic poles of the electromagnets surrounding the rotor must rotate around it.

42. Fill in the gaps with the words from the box:

The genius of George Westinghouse and Nikola Tesla in the late 1800's was to realize that producing alternating current made it 1 ___ to transfer power easily from one electric circuit to another with the help of an electromagnetic 2 ___ called a transformer. When an alternating electric current passes through the primary wire coil of a transformer, the changing magnetic and electric fields that this current produces transfer power from that primary current to the current passing through another coil of wire — the secondary coil of the 3 ___. While no electric 4 ___ move between these two wires, electric power does. With the help of a transformer, it's possible for a generating 5 ___ to move power from a large current of relatively low energy electric charges — low voltage charges — to a small current of relatively high-energy electric charges — high voltage charges. This small current of high voltage electric charges can move with relatively little power loss through miles and miles of high voltage transmission lines and can go from the generating plant to a 6 ___ city without wasting much power.

Upon arrival at the city, this current can pass through the primary coil of another transformer and its power can be 7 ___ to a large current of relatively low voltage charges flowing through the secondary coil of that transformer. The latter current can then deliver this electric power to your neighborhood. A transformer can’t transfer power between two circuits if those circuits operate with 8 ___current. Edison tried to use direct current in his power 9 ___ systems. Edison even invented the electric chair to «prove» that alternating current was much more 10 ___ than direct current. Still, Westinghouse and Tesla won out in the end because they had the better idea.

Check your answers on p. 280.