magnetism

Question 1

What are the 2 ends of a bar magnet called?

Answer 1

south pole and north pole

Question 2

name two magnetic materials

Answer 2

iron and cobalt

Question 3

What happens if you arrange 2 magnets with their north poles close to each
other?

Answer 3

they repel

Question 4

How can you arrange 2 magnets so they attract each other?

Answer 4

place the opposite poles close together

Question 5

What is a magnetic field?

Answer 5

The area around a magnet where magnetic objects feel a force

Question 6

How can you find the shape of a magnetic field?

Answer 6

Use iron filings or plotting compasses

Question 7

Name 2 electrical devices that use magnets.

Answer 7

generators and loudspeakers

Question 8

why do compasses point north?

Answer 8

It’s in the earths magnetic field

Question 9

Describe the shape of the Earth’s magnetic field.

Answer 9

Similar to the field around a bar magnet

Question 10

Why are compass needles weighted at one end?

Answer 10

In most places the Earth’s magnetic field is not parallel to the surface

Question 11

Which part of the Earth is responsible for its magnetic field?

Answer 11

the outer core

Question 12

What is the difference between the North Pole and the north magnetic pole of the Earth?

Answer 12

earth spins around the north pole, compasses point to the magnetic north

Question 13

What is an induced magnet?

Answer 13

an object that only turns into a magnet when it’s in a magnetic field if another magnet

Question 14

Which way does a plotting compass’ needle point when being used to plot the magnetic field around a bar magnet

Answer 14

towards south
away from north

Question 15

How does a magnetic field diagram show where the field is strongest?

Answer 15

where the lines are closest together

Question 16

What is a uniform magnetic field?

Answer 16

A magnetic field with the same strength everywhere

Question 17

how can you produce a uniform magnetic field?

Answer 17

using two flat magnets

Question 18

What shape is the magnetic field around a wire with a current flowing through
it?

Answer 18

circular around the wire

Question 19

What is an electromagnet?

Answer 19

a magnet made when current flows through a coil of wire

Question 20

How can you create a magnetic field around a wire?

Answer 20

pass a current through it

Question 21

Where is the magnetic field around a wire strongest?

Answer 21

closest to the wire

Question 22

How can you increase the strength of the magnetic field around a wire?

Answer 22

increase the current

Question 23

How can you change the direction of the magnetic field around the wire?

Answer 23

reverse the current

Question 24

What is a solenoid?

Answer 24

A coil of wire with a current flowing in it / Another name for an electromagnet

Question 25

Why is an electromagnet called a temporary magnet?

Answer 25

It's only magnetic when a current is flowing: you can turn it off!

Question 26

Describe the magnetic field inside a solenoid.

Answer 26

Strongest place, uniform, goes along the centre of the coil

Question 27

Why is the magnetic field of a solenoid stronger along the middle than outside it?

Answer 27

The **field from the two halves of the coil** reinforce each other in the middle and oppose each other outside.

Question 28

Describe the magnetic field between two flat magnets.

Answer 28

uniform

Question 29

What is the motor effect?

Answer 29

A force produced when a current flows inside a magnetic field

Question 30

How can we MAKE a magnetic field that can be turned on and off (temporary magnet)?

Answer 30

flow a current through a wire

Question 31

In terms of poles, which way does a magnetic field go?

Answer 31

n to s

Question 32

What is the name of the effect of a wire feeling a force if it has a current in it and it is in a magnetic field?

Answer 32

the motor effect

Question 33

How is the wire with the current arranged compared to the magnetic field for it to feel the greatest force?

Answer 33

at right angles

Question 34

What connects the motor to the external circuit?

Answer 34

split ring commutator

Question 35

What are on the ends of the wires that touch this?

Answer 35

carbon brushes

Question 36

Give 2 ways of increasing the strength of the motor effect.

Answer 36

increase current increase strength of magnetic field

Question 37

What does magnetic flux density measure?

Answer 37

strength of magnetic field

Question 38

What are the units of magnetic flux density?

Answer 38

tesla

Question 39

What happens when you move a wire in a magnetic field?

Answer 39

a current or voltage induced in the wire