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Physics > Magnetism and Electromagnetism > Flashcards

Magnetism and Electromagnetism Flashcards

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1
Q

Two magnets are brought very close together but do not touch. Do they exert a force on each other?

A

yes

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2
Q

The two poles on a bar magnet are called the north and the __________ pole.

A

south

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3
Q

Which of these materials is magnetic?

A

cobalt

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4
Q

Which type of magnet would you use to hold up a picture on a fridge door?

A

permanent magnet

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5
Q

In a magnet, the magnetic field is strongest at the points called the __________.

A

poles

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6
Q

In a bar magnet we can say that unlike poles do what?

A

attract

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7
Q

Iron usually forms only an __________ magnet that loses its magnetism when moved away from a magnetic source.

A

induced

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8
Q

The needle of a compass points towards the Earth’s… what?

A

geographic north pole

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9
Q

A magnet that keeps its magnetism after being moved away from a magnet is referred to as which type of magnet?

A

permanent magnet

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10
Q

In a bar magnet we say that like poles do what?

A

repel

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11
Q

When a piece of iron is placed next to a magnet it also becomes magnetised. This type of magnetism is called __________ magnetism.

A

induced

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12
Q

The magnetic field around a bar magnet is strongest at its poles. We can see this on the diagram below, where the magnetic field lines are more __________ at the ends of the magnet.

A

concentrated

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13
Q

The region around a magnet where a force acts on another magnet is called the magnetic __________.

A

field

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14
Q

If two bar magnets are brought together will the north pole of the first magnet attract or repel the south pole of the second magnet?

A

attract

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15
Q

If two bar magnets are brought together will the south pole of the first magnet attract or repel the south pole of the second magnet?

A

repel

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16
Q

When we show the direction of a magnetic field at a certain point, we are showing the direction of the force that would act on a __________ pole placed at that point.

A

north

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17
Q

What is the direction of the magnetic field line in a magnet?

A

north pole to south pole

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18
Q

A magnet has a magnetic __________ around it.

A

field

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19
Q

What type of force exists between a magnet and a magnetic material?

A

attraction

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20
Q

Induced magnetism always causes a force of ___________.

A

attraction

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21
Q

A magnet’s __________ are where its magnetic forces are the strongest.

A

poles

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22
Q

Steel usually forms a __________ magnet that keeps its magnetism when moved away from a magnetic source.

A

permanent

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23
Q

Which of these is a reason electromagnets are sometimes more useful than permanent magnets?

A

electromagnets can be switched off and on

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24
Q

What shape will the magnetic field around a straight wire carrying an electric current be?

A

circular

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25
Q

True or false? Electric currents always produce magnetic fields.

A

true

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26
Q

True or false? Electromagnets are a type of permanent magnet.

A

false

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27
Q

True or false? A cable that connects an electrical appliance to the mains will have a magnetic field around it when the appliance is being used.

A

true

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28
Q

An electromagnet is a __________ with an iron core.

A

solenoid

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29
Q

An advantage of electromagnets over bar magnets is that you can easily vary the __________ of the magnetic field.

A

strength

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30
Q

True or false? The magnetic field around a solenoid is the same shape as the magnetic field around a bar magnet.

A

true

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31
Q

A __________ is a long coil of wire.

A

solenoid

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32
Q

A solenoid is a…

A

long coil of wire

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33
Q

The _________ of the magnetic field depends on the direction of the current.

A

direction

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34
Q

The direction of the ____________ _______ depends on the direction of the current.

A

magnetic field

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35
Q

The direction of the magnetic field depends on the ___________ of the current.

A

direction

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36
Q

The direction of the magnetic field depends on the direction of the ________.

A

current

37
Q

The ________ of the magnetic field depends on the direction of the current.

A

direction

38
Q

The direction of the ____________ _______ depends on the direction of the current.

A

magnetic field

39
Q

The direction of the magnetic field depends on the direction of the _________.

A

current

40
Q

What name is given to a magnet produced by an electric current?

A

electromagnet

41
Q

A straight wire and a solenoid each have a current of 6 amperes running through them. Which will have a weaker magnetic field?

A

straight wire

42
Q

Wrapping a _____ into a solenoid (coil) will make the magnetic field stronger

A

wire

43
Q

Wrapping a wire into a _________ (coil) will make the magnetic field stronger

A

solenoid

44
Q

Wrapping a wire into a solenoid (coil) will make the __________ _____ stronger

A

magnetic field

45
Q

Wrapping a wire into a solenoid (coil) will make the magnetic field __________

A

stronger

46
Q

__________ a wire into a solenoid (coil) will make the magnetic field stronger

A

wrapping

47
Q

What will happen to the magnetic field strength of a solenoid if an iron core is added to it?

A

it will increase

48
Q

A wire with a current running through it can be shaped into a tightly wound coil in order to increase the magnetic field it creates. What is the name of the tightly wound coil shape?

A

solenoid

49
Q

what is a solenoid?

A

a coil of wire

50
Q

what is a coil of wire called?

A

solenoid

51
Q

True or false? Electromagnets are often used to lift iron and steel scrap in scrapyards.

A

true

52
Q

True or false? A solenoid always has a magnetic field around it, even when it is not carrying an electric current.

A

false

53
Q

Which type of magnets can be turned on and off using electricity?

A

electromagnets

54
Q

The motor effect happens because the current-carrying wire produces a __________ __________ that interacts with the field of the magnet.

A

magnetic field

55
Q

True or false? When using Fleming’s left-hand rule, the thumb and fingers must be at right-angles to one another.

A

true

56
Q

What units are used for force?

A

newton

57
Q

What units are used for current?

A

ampere

58
Q

Which equation connects force, magnetic flux density, current and length together?

A

force = magnetic flux density x current x length

59
Q

______ = magnetic flux density x current x length

A

force

60
Q

force = __________ ____ _______ x current x length

A

magnetic flux density

61
Q

force = magnetic flux density x ________ x length

A

current

62
Q

force = magnetic flux density x current x ______

A

length

63
Q

When using Fleming’s left-hand rule, the first finger points in the direction of the… what?

A

magnetic field

64
Q

What effect would increasing the strength of the magnetic field have on the force caused by the motor effect?

A

increase it

65
Q

True or false? When using Fleming’s left-hand rule, the direction of the magnetic field is taken to be from south to north.

A

false

66
Q

Loudspeakers and headphones use the __________ effect to make pressure variations in sound waves.

A

motor effect

67
Q

Will there be a force on a current-carrying wire in a magnetic field if the current and fields are parallel?

A

no

68
Q

The ________ and the magnetic field lines need to be at right angles to produce a force.

A

current

69
Q

The current and the ________ ______ lines need to be at right angles to produce a force.

A

magnetic field

70
Q

The current and the magnetic field lines need to be at _____ ________ to produce a force.

A

right angles

71
Q

The current and the magnetic field lines need to be at right angles to produce a ______.

A

force

72
Q

If a wire carrying an electric current is placed in a magnetic field, a force is produced. What name is given to this effect?

A

motor effect

73
Q

When using Fleming’s left-hand rule, the second finger points in the direction of the __________.

A

current

74
Q

Would increasing the strength of the magnetic field have an effect on the direction of the force caused by the motor effect?

A

no

75
Q

A wire carries a current of 2A through a magnetic field. The wire experiences a force. What will happen to the size of this force if the current is reversed?

A

stays the same

76
Q

When using Fleming’s left-hand rule, the thumb points in the direction of the… what?

A

force

77
Q

Loudspeakers receive energy through __________ and transfer it into the surroundings in sound.

A

electricity

78
Q

What units are used for magnetic flux density?

A

tesla

79
Q

__________’s Left Hand Rule is used to predict the direction of the force on a current-carrying wire.

A

Fleming

80
Q

Louis is studying a current-carrying wire in a magnetic field. Name the rule that he can use to work out the direction of the force from the direction of the current and the magnetic field.

A

Fleming’s left hand rule

81
Q

Will there be a force on a current-carrying wire in a magnetic field if the current and fields are at right-angles to one another?

A

yes

82
Q

A wire carries a current through a magnetic field. A force on the wire makes it move left. In which direction would the wire move if the direction of the magnetic field was reversed?

A

right

83
Q

Name an example of an everyday application that does NOT contain a motor?

A

kettle

84
Q

The diagram shows a wire carrying an electric current. This wire is made from copper, which is not a magnetic material. Will the wire still move?

A

yes

85
Q

A wire carries a current of 2A through a magnetic field. The wire experiences a force. What will happen to the size of this force if the current is changed to 1A?

A

decrease

86
Q

True or false? A current-carrying straight wire placed in a magnetic field can move because it experiences a force.

A

true

87
Q

Loudspeakers and headphones convert changes in the __________ of electrical circuits into pressure variations in sound waves.

A

current

88
Q

Which hand would you use to work out the direction of the force from the direction of the current and magnetic field for a current-carrying wire in a magnetic field?

A

left

89
Q

A wire is carrying an electric current through a magnetic field. A force on the wire makes it move to the right. In which direction would the wire move if the current in the wire changed direction?

A

left

Physics (7 decks)

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