Chapter 17, Magnetism

10. Electric current from a generating plant is

alternating current transmitted at high voltages, but usually used at low voltages.

15. What device transforms electrical energy into mechanical energy?

an electric motor

42. What common electrical device is shown in diagram C?

an electric motor

37. To generate electricity at an electric company, a turbine is attached to the ____________________ of a generator.

armature

29. When placed near each other, unlike magnetic poles ____________________ each other.

attract

3. Magnetic poles that are unlike

attract each other

8. As Earth's magnetic poles move, the magnetic declination in a given location will

change

35. The distance that the pointer of a galvanometer moves depends on the amount of ____________________ in the loops of the armature.

current

24. A galvanometer is a device that measures small ____________________.

currents

36. A current consisting of charges that flow in one direction only is called a(n) ____________________ current.

direct current

6. The type of current produced by a battery is

direct current

13. A solenoid with a ferromagnetic core is called a(n)

electromagnet

27. A(n) ____________________ is a strong magnet that can be turned on and off.

electromagnet

18. A magnetic pole is the part of a magnet where the magnetic effect is weakest. ____________________

false Strongest

34. A solenoid with a(n) ____________________ core is called an electromagnet.

ferromagnetic field

32. Magnetic ____________________ spread out from one pole, curve around the magnet, and return to the other pole.

field lines

14. A device used to measure small currents is a(n)

galvanometer

49. If the number of loops in the secondary coil of transformer A is reduced, what will happen to the voltage in the secondary coil?

it will decrease

38. According to diagram A, in which direction will the upper loop of the wire move?

it will move downard

39. In which direction would the wire move in diagram A if the direction of the current were reversed?

it will move upward

28. A(n) ____________________ is any material that attracts iron and materials that contain iron.

magnet

31. A(n) ____________________ is the region of magnetic force around a magnet.

magnetic field

33. A(n) ____________________ is produced around a wire through which a current flows.

magnetic field

9. An electric current produces a(n)

magnetic field

When a wire moves up or down repeatedly in a ________, an alternating current is induced in the wire.

magnetic field

30. The attraction or repulsion between magnetic poles is called ____________________.

magnetic force

45.Which pair of magnets is arranged so that like poles are placed near each other?

magnetic pair b

46.Which pair of magnets is arranged so that opposite poles are placed near each other?

magnetic pair c

2. Every magnet, regardless of its shape, has two

magnetic poles.

16. A generator transforms

mechanical energy into electrical energy

44.Based on the diagram, where is the magnetic force around magnet A the strongest? How can you tell?

near the poles

12. The two ends of a solenoid act like

poles of a magnet

11. Magnetic poles that are alike

repel each other

41. Describe two ways of causing the loop to rotate in the opposite direction in diagram B.

reverse the direction of the current or reverse the direction of the magnet

1. Magnetic field lines around a bar magnet

spread out from one pole and curve around to the other

47.What type of transformer is transformer B?

step up transformer

48.Identify the parts labeled C and D.

step up transformer

43. What is each curved line around magnet A called?

the magnetic field lines are closer together in those areas

40. Look at the circular arrow in diagram B. Which side of the loop is moving up?

the side close to the magnetic pole

50. What would the voltage be in the secondary coil of transformer A if the number of loops in the secondary coil were made to be the same as the number of loops in the primary coil?

the voltage in the secondary coil would be the same as the voltage in the primary coil

5. To reverse the direction of current in a motor, current is conducted

through the brushes to the commutator

17. A device that increases or decreases voltage is called a(n)

transformer

20. A DC generator is like an AC generator, except that it contains a(n) commutator instead of slip rings. ____________________

true

22. Magnets attract iron. ____________________

true1

7. You can increase the strength of an electromagnet's field by

using a stronger ferromagnetic material for the core

26. A step-up transformer is a transformer that increases ____________________.

voltage

19. A compass behaves as it does because the moon acts as a giant magnet. ____________________

False, Earth

21. Increasing the number of loops in a solenoid will cause the strength of its magnetic field to decrease. ____________________

False, increase

4. What is one difference between a galvanometer and an electric motor?

In an electric motor, the armature spins continuously

23. A maglev train floats above its rails due to ____________________.

Magnetism