P1.6 Electromagnetic Waves

Question 1

Name the electromagnetic waves from shortest wavelength to longest.

Answer 1

Gamma
X-rays
Ultra-violet
(Visible) Light
Infrared
Microwaves
Radio

Question 2

What are the features of gamma waves on the em spectrum?

Answer 2

High frequency
Short wavelength
High energy

Question 3

What type of of wave are all electromagnetic waves?

Answer 3

Transverse

Question 4

What is the speed of electromagnetic waves?

Answer 4

3 X 10 to the power 8 m/s

Question 5

How do you work out the frequency of a wave?

Answer 5

Speed / wavelength

Question 6

What are the uses of radio waves?

Answer 6

Connects devices like Bluetooth or wireless connections

Wifi, radio and to

Question 7

What are the uses of microwaves?

Answer 7

Communications
Beam signals (can heat food)

Question 8

What are the uses of infrared?

Answer 8

Optical fibres to transmit signals like a remote

Can see people in darkness

Question 9

What are the uses of visible light?

Answer 9

Cameras - digital and film

Produce pixels

Question 10

What are the dangers of radio waves?

Answer 10

Very high frequencies in radar towers

Question 11

What are the dangers of microwaves?

Answer 11

Cooks through tissues and can dry out your body

Internal tissue bleeding

Question 12

What’s the danger of infrared?

Answer 12

Can burn you

Question 13

What’s the danger of visible light?

Answer 13

Blindness

Question 14

What can’t radio waves travel through?

Answer 14

The atmosphere

Question 15

What’s the Doppler effect?

Answer 15

As an ambulance travels forward: the wave front is compressed, decreasing its wavelength and increasing the frequency.
The wave behind is stretched out, increasing its wavelength and decreasing its frequency.

Question 16

What waves can be the Doppler effect?

Answer 16

Light
Sound
Microwaves

Question 17

What’s red shift?

Answer 17

Light from galaxies is shifted towards the red end of the spectrum, increasing wavelength.
This proves they’re moving away from us and is a huge piece of evidence to show the universe is expanding.

Question 18

What’s the Big Bang theory?

Answer 18

The universe started at a very small single point (singularity). Nothing else anywhere. This contained all the matter and energy.
There was a big explosion and the matter expanded outwards in all directions.
As it began to cool stars and planets began to form.
The universe has been expanding ever since.

Question 19

What’s CMBR?

Answer 19

Cosmic microwave background radiation
Key piece of evidence for the Big Bang. CMBR is electromagnetic radiation remaining from the Big Bang explosion and fills the whole of the universe.

Question 20

Why are optical fibres useful?

Answer 20

They carry much more information and are more secure than radio waves and microwave transmissions.

Question 21

What’s blue-shift?

Answer 21

Indicates a galaxy is moving towards us

Question 22

How do we know the universe is expanding?

Answer 22

Red shift proves all galaxies are moving away from each other meaning the universe must be expanding.

Question 23

What is the range of wavelength of electromagnetic waves?

Answer 23

10 to the -15 m
To
10 to the 4 m (10000m)