Magnetism and Electromagnetism

Question 1

Where on a magnet are the magnetic forces strongest?

Answer 1

At the poles

Question 2

What happens when two opposite poles are brought together?

Answer 2

They attract

Question 3

What happens when two like poles are brought together?

Answer 3

They repel

Question 4

Is magnetism a contact or non-contact force?

Answer 4

Non-contact

Question 5

What is a permanent magnet?

Answer 5

A material that produces its own magnetic field

Question 6

What is a temporary magnet?

Answer 6

A material that is only magnetic when placed in a magnetic field, will lose its magnetism when removed

Question 7

When does a wire generate a magnetic current?

Answer 7

When current is flowing through it

Question 8

For the right hand rule, what does the thumb represent?

Answer 8

The direction of the current

Question 9

For the right hand rule, what do the fingers represent?

Answer 9

The direction of the magnetic field

Question 10

What does the strength of the magnetic field around a wire depend on?

Answer 10

The size of the current, distance from the wire

Question 11

What is a solenoid?

Answer 11

A coil of wire

Question 12

What is an electromagnet?

Answer 12

A coil of wire with an iron core

Question 13

How can an electromagnet be made stronger?

Answer 13

More coils, increased current, soft iron core

Question 14

What is the motor effect?

Answer 14

When a conductor carrying a current is placed in a magnetic field, the conductor and magnet exert a force on each other

Question 15

For Fleming’s left hand rule, what does the thumb represent?

Answer 15

The direction of movement/motion

Question 16

For Fleming’s left hand rule, what does the first finger represent?

Answer 16

The direction of the magnetic field

Question 17

For Fleming’s left hand rule, what does the second finger represent?

Answer 17

The direction of the current

Question 18

What equation links current, length, force and magnetic flux?

Answer 18

Force = Magnetic flux x Current x Length

Question 19

What are the units for magnetic flux?

Answer 19

Tesla, T

Question 20

What are the units for current?

Answer 20

Amps, A

Question 21

What are the units for force?

Answer 21

Newtons, N

Question 22

What is a compass?

Answer 22

A small, suspended bar magnet which points North

Question 23

What is a compass used for?

Answer 23

Navigation using the Earth’s magnetic field

Question 24

Why does the Earth have a magnetic field?

Answer 24

The liquid iron and nickel outer core moves around the solid iron and nickel core

Question 25

What is a pole reversal?

Answer 25

When the location of the magnetic North and South pole are reversed

Question 26

Where is the magnetic North pole located?

Answer 26

The geographic South pole

Question 27

Where is the magnetic South pole located?

Answer 27

The geographic North pole

Question 28

What are the consequences of a pole reversal?

Answer 28

Changes in animal migration, compasses point in the wrong direction

Question 29

What evidence is there for pole reversals?

Answer 29

Sea floor spreading

Question 30

What is an electric motor?

Answer 30

A coil or wire rotating within a magnetic field

Question 31

What is the function of a split ring commutator?

Answer 31

Swaps the direction of the current every half turn to allow 360 degree rotation

Question 32

How can the speed of an electric motor be increased?

Answer 32

Increase the number of coils, use a stronger magnet, increase the current

Question 33

What is a magnetic field?

Answer 33

The area around a magnet where the magnetic force can be felt

Question 34

Name four magnetic materials

Answer 34

Iron, nickel, cobalt, steel

Question 35

How can you tell the difference between a permanent and a temporary magnet?

Answer 35

Permanent magnets can both attract and repel other magnets, temporary magnets can only attract other magnetic materials

Question 36

In what direction do magnetic field lines run?

Answer 36

From North to South