Magnetism and Electromagnetism Flashcards
Two magnets are brought very close together but do not touch. Do they exert a force on each other?
yes
The two poles on a bar magnet are called the north and the __________ pole.
south
Which of these materials is magnetic?
cobalt
Which type of magnet would you use to hold up a picture on a fridge door?
permanent magnet
In a magnet, the magnetic field is strongest at the points called the __________.
poles
In a bar magnet we can say that unlike poles do what?
attract
Iron usually forms only an __________ magnet that loses its magnetism when moved away from a magnetic source.
induced
The needle of a compass points towards the Earth’s… what?
geographic north pole
A magnet that keeps its magnetism after being moved away from a magnet is referred to as which type of magnet?
permanent magnet
In a bar magnet we say that like poles do what?
repel
When a piece of iron is placed next to a magnet it also becomes magnetised. This type of magnetism is called __________ magnetism.
induced
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.
concentrated
The region around a magnet where a force acts on another magnet is called the magnetic __________.
field
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?
attract
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?
repel
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.
north
What is the direction of the magnetic field line in a magnet?
north pole to south pole
A magnet has a magnetic __________ around it.
field
What type of force exists between a magnet and a magnetic material?
attraction
Induced magnetism always causes a force of ___________.
attraction
A magnet’s __________ are where its magnetic forces are the strongest.
poles
Steel usually forms a __________ magnet that keeps its magnetism when moved away from a magnetic source.
permanent
Which of these is a reason electromagnets are sometimes more useful than permanent magnets?
electromagnets can be switched off and on
What shape will the magnetic field around a straight wire carrying an electric current be?
circular
True or false? Electric currents always produce magnetic fields.
true
True or false? Electromagnets are a type of permanent magnet.
false
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.
true
An electromagnet is a __________ with an iron core.
solenoid
An advantage of electromagnets over bar magnets is that you can easily vary the __________ of the magnetic field.
strength
True or false? The magnetic field around a solenoid is the same shape as the magnetic field around a bar magnet.
true
A __________ is a long coil of wire.
solenoid
A solenoid is a…
long coil of wire
The _________ of the magnetic field depends on the direction of the current.
direction
The direction of the ____________ _______ depends on the direction of the current.
magnetic field
The direction of the magnetic field depends on the ___________ of the current.
direction
The direction of the magnetic field depends on the direction of the ________.
current
The ________ of the magnetic field depends on the direction of the current.
direction
The direction of the ____________ _______ depends on the direction of the current.
magnetic field
The direction of the magnetic field depends on the direction of the _________.
current
What name is given to a magnet produced by an electric current?
electromagnet
A straight wire and a solenoid each have a current of 6 amperes running through them. Which will have a weaker magnetic field?
straight wire
Wrapping a _____ into a solenoid (coil) will make the magnetic field stronger
wire
Wrapping a wire into a _________ (coil) will make the magnetic field stronger
solenoid
Wrapping a wire into a solenoid (coil) will make the __________ _____ stronger
magnetic field
Wrapping a wire into a solenoid (coil) will make the magnetic field __________
stronger
__________ a wire into a solenoid (coil) will make the magnetic field stronger
wrapping
What will happen to the magnetic field strength of a solenoid if an iron core is added to it?
it will increase
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?
solenoid
what is a solenoid?
a coil of wire
what is a coil of wire called?
solenoid
True or false? Electromagnets are often used to lift iron and steel scrap in scrapyards.
true
True or false? A solenoid always has a magnetic field around it, even when it is not carrying an electric current.
false
Which type of magnets can be turned on and off using electricity?
electromagnets
The motor effect happens because the current-carrying wire produces a __________ __________ that interacts with the field of the magnet.
magnetic field
True or false? When using Fleming’s left-hand rule, the thumb and fingers must be at right-angles to one another.
true
What units are used for force?
newton
What units are used for current?
ampere
Which equation connects force, magnetic flux density, current and length together?
force = magnetic flux density x current x length
______ = magnetic flux density x current x length
force
force = __________ ____ _______ x current x length
magnetic flux density
force = magnetic flux density x ________ x length
current
force = magnetic flux density x current x ______
length
When using Fleming’s left-hand rule, the first finger points in the direction of the… what?
magnetic field
What effect would increasing the strength of the magnetic field have on the force caused by the motor effect?
increase it
True or false? When using Fleming’s left-hand rule, the direction of the magnetic field is taken to be from south to north.
false
Loudspeakers and headphones use the __________ effect to make pressure variations in sound waves.
motor effect
Will there be a force on a current-carrying wire in a magnetic field if the current and fields are parallel?
no
The ________ and the magnetic field lines need to be at right angles to produce a force.
current
The current and the ________ ______ lines need to be at right angles to produce a force.
magnetic field
The current and the magnetic field lines need to be at _____ ________ to produce a force.
right angles
The current and the magnetic field lines need to be at right angles to produce a ______.
force
If a wire carrying an electric current is placed in a magnetic field, a force is produced. What name is given to this effect?
motor effect
When using Fleming’s left-hand rule, the second finger points in the direction of the __________.
current
Would increasing the strength of the magnetic field have an effect on the direction of the force caused by the motor effect?
no
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?
stays the same
When using Fleming’s left-hand rule, the thumb points in the direction of the… what?
force
Loudspeakers receive energy through __________ and transfer it into the surroundings in sound.
electricity
What units are used for magnetic flux density?
tesla
__________’s Left Hand Rule is used to predict the direction of the force on a current-carrying wire.
Fleming
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.
Fleming’s left hand rule
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?
yes
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?
right
Name an example of an everyday application that does NOT contain a motor?
kettle
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?
yes
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?
decrease
True or false? A current-carrying straight wire placed in a magnetic field can move because it experiences a force.
true
Loudspeakers and headphones convert changes in the __________ of electrical circuits into pressure variations in sound waves.
current
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?
left
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?
left
