Download CHAPTER 18 - QUESTIONS 1-3

CHAPTER 18 - QUESTIONS 1-3
1. Describe the properties of magnets. 2 poles, exert magnetic force,
surrounded by magnetic field
2. Explain why some materials are magnetic and some are not. The
arrangement of the atoms (called domains) determine whether an
object is magnetic or not.
3. Describe 4 kinds of magnets.
Ferromagnets – made of iron, nickel, cobalt, etc.
Electromagnets – magnet made by an electric current
Temporary Magnets – made from materials that are easy to
magnetize –
lose magnetism easily
Permanent Magnets – difficult to magnetize, but keep magnetism
indefinitely
CHAPTER 18 - QUESTIONS 4-6
4. Give 2 examples of the effect of Earth’s magnetic
field. Poles like a compass needle, Spinning electrons
cause movement ; magnetic field
5. If 2 magnets push each other away, what can you
conclude about their poles? They carry the same
charge.
6. Why are copper and aluminum not magnetic? Their
atomic structure does not allow for it.
CHAPTER 18 - QUESTIONS 7-9
7. Describe 2 ways a magnet can lose its magnetic
properties. Striking it or heating it
8. What are ferromagnets? Magnets made with iron,
nickel, or cobalt
9. What do scientists think causes Earth’s magnetic
field? The movement of electric charges at Earth’s
solid inner core (made of iron and nickel).
CHAPTER 18 - QUESTIONS 10-12
10. Identify the relationship between an electric current and a magnetic
field. A current carrying wire causes a magnet to move.
11. Compare solenoids and electromagnets. Solenoids: a coil of wire with
an electric current running through it. Electromagnet: a magnet that has
an electric current attached that can be switched on and off. A solenoid
is part of an electromagnet.
12. Describe how electromagnetism is involved in the operation of
doorbells, electric motors, and galvanometers. An electric current moves
in a solenoid that is attached to a magnetic material . This allows the
electric current to move so your doorbell rings, motor runs, and
galvanometer to measure the movement.
CHAPTER 18 - QUESTIONS 13-15
13. What is electromagnetism? The interaction between electricity
and magnetism.
14. What happens to the magnetic field of an electromagnet if you
increase the current in the wire? The field gets bigger or
stronger.
15. Why does a current carrying wire cause a compass needle to
move? The electric current creates a magnet field that exerts a
force on the compass needle and causes it to move.
CHAPTER 18 – QUESTIONS 16-18
16. What does a galvanometer measure? Current
17. Explain how a magnetic field can make an electric current. The
movement in a magnetic field induces (makes it move without
touching it) an electric current.
18. Explain how electromagnetic induction is used in a generator.
Electromagnetic induction is used to change mechanical energy
to electrical energy.
CHAPTER 18 – QUESTIONS 19-21
19. Compare step-up and step-down transformers. Stepup increase voltage; Step-down decreases voltage.
20. What was Faraday trying to do in his experiment?
Prove that an electromagnet could induce an electric
current.
21. What energy change happens in an electric
generator? Changes mechanical energy to
mechanical energy.
CHAPTER 18 – QUESTIONS 22-23
22. What are 3 sources of energy that are used to
generate electrical energy? Nuclear reaction, fossil
fuels, and wind.
23. What does a transformer do? Increases or decreases
the voltage of an alternating current.
24. What is AC and DC? AC = Alternating Current –
current travelling in both directions. DC = Direct
Current – current travelling in one direction.