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