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Flashcards in Abeka Science Chapter 14 Deck (60):
0

What did the Vikings use to navigate when clouds covered the sun and stars?

Lodestone

1

What is an object capable of attracting materials such as iron or steel by magnetic force?

A magnet

2

What is the property of attracting objects by the magnetic force?

Magnetism

3

What did Pélerin call the pole that points northward?

The north pole

4

What did Pélerin call the pole that points south?

The south pole

5

What law states that unlike poles attract each other, but like poles repel each other?

The law of magnetic poles

6

What is the region surrounding a magnet in which other objects are affected by magnetism?

The magnetic field

7

What imaginary lines indicate the direction and strength of the magnetic field?

Lines of flux

8

What law states that the force between two magnetic poles is directly related to the product of the pole strengths and inversely related to the square of the distance between the poles?

The law of magnetic force

9

What is this Greek letter called? κ

kappa

10

The extent to which a material can be absorbed or channel lines of magnetic flux is called _______.

permeability

11

True or False:
Magetic fields are produced by the motion of electrons (and other charged particles)

True

12

What is the most important cause of magnetism in magnetic materials?

electron spin

13

By what can the two types of motion be described?

quantum numbers

14

What is a group of aligned atoms having a single magnetic field called?

a domain

15

What does MRI mean?

magnetic resonance imaging

16

What does NMR mean?

nuclear magnetic resonance

17

What do chemists use to help determine the structure of organic molecules?

NMR spectroscopy

18

What idea does our understanding of what makes a magnet work depend on?

The domain theory

19

True or False:
The magnetic field of a magnet is the sum of the fields of thousands of magnetic domains.

True

20

True or False:
A magnetic substance forms a magnet onlu if is domains are mostly aligned.

True

21

What are substances with no unpaired electrons known as?

diamagnetic substances

22

What word describes a material weakly attracted to a magnet?

paramagnetic

23

What word describes substances that have several unpaired electrons per atom, making them strongly attracted to magnets?

ferromagnetic

24

What are substances that can be quickly magnetized even in a weak magnetic field considered to be?

magnetically soft

25

What is a magnet made from a magnetically soft material called?

temporary magnet

26

What are materials whose domains strongly resist changes in the direction of their magnetic fields known as?

magnetically hard

27

What are magnets made from magnetically hard materials called?

permanent magnets

28

What process occurs when a steel needle is made into a magnet by stroking it with another magnet?

Magnetization by contact.

29

Is magnetization by contact permanant or temporary?

It can be both.

30

What is temporary magnetization caused by placing an object within a magnetic field called?

Magnetizing by induction.

31

True or False:
Whenever electricity flows through a wire, a magnetic field is produced around the wire.

True

32

What kind of magnetization did Hands Christian Oersted discover that had to do with electricity?

Magnetization by electricity.

33

How may the direction of the lines of flux be determined?

Through the left hand rule.

34

What is a device that produces a strong magnetic field when electricity passes through it?

An electromagnet

35

What is the manetically soft material placed within the coils of an electromagnet in order to strengthen its field?

core

36

How is the strength of the magnetic field produced by an electric current related to the square of the current?

directly related

37

True or False: The strength of an electromagnet is also proportional to the number of loops of wire in the coil.

True

38

What are materials called that allow tremendous quantities of electricity to flow through them unhindered?

Superconductors

39

True or False:
Permanent magnets cannot lose their magnetism.

False. Although they do not easitly lose their magnetism, under certain conditions they can lose their strength or even become demagnetized altogether.

40

What is the temperature at which ferromagnetic material's domains dissappear?

Its Curie point

41

What is the force existing in a magnetic field that causes a moving electric charge to deviate from its original path called?

deflecting force

42

What is the piece of permeable metal called that channels the lines of flux and preserves the poles of a horshoe magnet?

the keeper

43

What is a navigational device consisting of a magnet free to swing horixontally so that it always points north?

a magnetic compass

44

Who discovered that a compass always points north because it is guided by the earth's magnetic field?

William Gilbert

45

What book did William Gilbert write on his findings?

De Magnete

46

What pole is located off the coast of Wilkes Land in Antarctica?

The south magnetic pole

47

True or False:
The earth's geographic and magnetic poles are the same.

False: The earth's poles are named after their geographic locations, but the magnetic poles are actually opposite.

48

What is the deviation called when a compass needle is off a few degrees from pointing to true north?

angle of declination

49

What is the deviation called when a compass needle is off a few degrees from pointing to true north?

angle of declination

50

What lines on a map can show the angle of declination for the entire earth?

isogonic lines

51

What is the line connecting all points where the compass needle points true north called?

The agonic line

52

What is the phenomenon called when a dipping needle points downward toward the earth in the northern hemisphere?

inclination, or magnetic dip

53

What are the horizontal (east-west) lines that connect locations having equal inclination called?

isoclinic lines

54

What imaginary line circles the earth halfway between the two magnetic poles?

The magnetic equator

55

What is the extent of a planet's magnetic field in space?

magnetosphere

56

By what is the magnetosphere distorted? It is a stream of plasma that emanates from the sun.

solar wind

57

What is the outer boundary of the magnetosphere?

the magnetopause

58

What are to vast, doughnut-shaped belts of high-speed charged particles?

Van Allen radiation belts

59

What is the fantastic display of shimmering lights known as?

The aurora