Magnetism and the Motor effect

Question 1

What are the Two poles in a magnet?

Answer 1

North and South Pole.

Question 2

What is a Magnetic Field?

Answer 2

A region where other magnets or magnetic materials experience a force.

Question 3

Where do the Magnetic field lines go from?

Answer 3

North to South.

Question 4

The closer together the lines are…

Answer 4

The stronger the magnetic field.

Question 5

The further away from a magnet you get…

Answer 5

The weaker the field is.

Question 6

Where is the magnetic field the strongest?

Answer 6

At the poles of a magnet.

Question 7

Between two magnets, if the poles are the same what will happen?

Answer 7

It will repel each other.

Question 8

What would two unlike poles do?

Answer 8

Attract each other.

Question 9

What does it create by placing the north and south poles of two bar magnets near each other?

Answer 9

A uniform field between the two poles.

Question 10

What is inside a compass?

Answer 10

A tiny bar magnet called a needle.

Question 11

What does a compass needle always do when near a magnet?

Answer 11

Line up with the magnetic field it’s in and Point towards the South Pole of a magnet.

Question 12

What happens when a compass is not near a magnet?

Answer 12

Always points towards the Earth’s North Pole. This is because the earth generates its own magnetic field. This shows the inside of the Earth must be magnetic.

Question 13

What are the 3 main magnetic elements?

Answer 13

Iron, Nickel and Cobalt.

Question 14

What happens when you put a magnetic material near a magnet?

Answer 14

It is attracted to that magnet.

Question 15

The magnetic force between a magnet and a magnetic material is…

Answer 15

Always attractive.

Question 16

What are Permanent Magnets?

Answer 16

Produce their own magnetic field all the time.

Question 17

What are Induced Magnets?

Answer 17

Only produce a magnetic field while they’re in another magnetic field. If you put any magnetic material into a magnetic field, it becomes an induced magnet.

Question 18

What does magnetic induction explain?

Answer 18

Why the force between a magnet and magnetic material is always attractive.

Question 19

What happens when you take away the magnetic field?

Answer 19

Induced magnets return to normal and stop producing a magnetic field.

Question 20

What does how quickly they lose their magnetism depend on?

Answer 20

The material they’re made from.

Question 21

What are permanent magnets made from?

Answer 21

Magnetically hard materials.

Question 22

Magnetically soft materials lose their magnetism very…

Answer 22

Quickly.

Question 23

What happens when current flows through a long, straight conductor?

Answer 23

A magnetic field is created around it.

Question 24

What is the field made up of?

Answer 24

Concentric circles perpendicular to the wire, with the wire in the centre.

Question 25

What happens when changing the direction of the current?

Answer 25

Changes the direction of the magnetic field.

Question 26

What rule is used to work out which way the direction of the magnetic field goes?

Answer 26

Right hand thumb rule.

Question 27

The larger the current through the wire, or the closer to the wire you are...

Answer 27

The stronger the field is.

Question 28

What is the Motor Effect?

Answer 28

A current carrying wire in the presence of a Magnetic Field will experience a force.

Question 29

What has to happen to experience the full force?

Answer 29

The wire has to be at 90 degrees to the magnetic field.

Question 30

How do we find the direction of the force?

Answer 30

Find the direction of the magnetic field and the direction of the current. By using Fleming's left hand rule.

Question 31

How do you use Fleming's left hand rule?

Answer 31

Using your left hand, point your First finger in the direction of the magnetic field and your seCond finger in the direction of the Current. Your thumb will then point in the direction of the force.

Question 32

How do we calculate the strength of the force?

Answer 32

F = B * I * L

Question 33

What is the Magnetic Flux density?

Answer 33

How many field lines there are in a region.

Question 34

What is I in the formula, F = B * I * L

Answer 34

Size of the current.

Question 35

What is a Solenoid?

Answer 35

A long coil of wire.

Question 36

How can you increase the strength of the magnetic field produced by a length of wire?

Answer 36

By wrapping it into a long coil with lots of loops. (Solenoid)

Question 37

What is the field like inside the solenoid?

Answer 37

You get lots of field lines pointing in the same direction. The magnetic field is strong and almost uniform.

Question 38

What is the field like outside the solenoid?

Answer 38

The overlapping field lines cancel each other out so the field is weak apart from at the ends of the solenoid.

Question 39

The direction of the field depends on...

Answer 39

The direction of the current.

Question 40

What is an Electromagnet?

Answer 40

A magnet with a magnetic field that can be turned on and off using an electric current.

Question 41

How can you increase the strength of the solenoid even more?

Answer 41

By putting a block of iron in the centre of the coil. This iron core becomes an induced magnet whenever current is flowing.

Question 42

What is Electromagnetic induction?

Answer 42

The induction of a potential difference in a wire which is experiencing a change in magnetic field.