JG Chapter 16 - Magnetism

Question 1

Which poles attract?

Answer 1

North and South

Question 2

How do magnets work?

Answer 2

A compass has a freely moving needle that is a magnet. The North Pole of the needle is attracted to the South Pole of the Earth’s internal magnet, indicating direction.

Question 3

What can all materials on earth be classified into?

Answer 3

Magnetic and non-magnetic materials

Question 4

What is a magnetic material?

Answer 4

a material that can be attracted by magnets and can be magnetised

Question 5

Define soft magnet and give an example

Answer 5

a material that once magnetised, is easy to demagnetise

e.g. iron

Question 6

Define hard magnet and give an example

Answer 6

a material that once magnetised is difficult to demagnetise

e.g. steel

Question 7

What are hard magnets used for?

Answer 7

• permanent magnets
• compass needles
• loudspeakers

Question 8

What are soft magnets used for?

Answer 8

• core of electromagnets (because they can be switched on and off)
• transformers

Question 9

What does it mean for a material to be magnetised?

Answer 9

it means that the material is able to attract

to be magnetised = to be able to attract

Question 10

What are non-magnetic materials? Give an example

Answer 10

materials that are not attracted by magnets and cannot be magnetised

e.g. plastic, rubber

Question 11

Define induced magnetism

Answer 11

when a magnetic material is only magnetised when placed in a magnetic field