Electromagnetic spectrum and uses

Question 1

What are all electromagnetic waves?

Answer 1

Transverse waves that travel at the same speed (or velocity) in a vacuum

Question 2

What is the order of electromagnetic waves from highest frequency to lowest?

Answer 2

Gamma
X-ray
Ultraviolet
Visible
Infrared
Microwave
Radio

Question 3

As you move from gamma rays to radio waves what happens to the wavelengths?

Answer 3

Wavelengths increase

Question 4

As you move from the gamma rays to radio waves, what happens to the frequencies?

Answer 4

Frequencies decrease

Question 5

What do electromagnetic waves transfer?

Answer 5

They transfer energy from the source of the wave to an absorber of the wave.

Question 6

Gamma rays carry the most ____ of all the electromagnetic waves.

Answer 6

Energy

Question 7

What are gamma rays used for?

Answer 7

Medical imaging and therapy, astronomy, sterilisation and food preservation.

Question 8

What are the risks of gamma ray usage?

Answer 8

Gamma rays are extremely penetrating and damaging to living tissues and cells.

Question 9

What can we use gamma rays to destroy?

Answer 9

Bacteria and tumours

Question 10

What can X-rays penetrate?

Answer 10

Soft materials (like body tissue).
- Bones are dense materials that absorb X-rays. We can use X-rays to build a shaded image of bones and body tissue.

Question 11

What are X-rays used for?

Answer 11

Medical and industrial imaging, to treat cancer and for security purposes to detect weapons in airports (and other places)

Question 12

X-rays are highly _____?

Answer 12

Ionising

Question 13

What does highly ionising mean?

Answer 13

Can damage body cells

Question 14

What are the safety precautions when dealing with X-rays?

Answer 14

Minimum exposure, appropriate shielding

Question 15

Where is ultraviolet light on the spectrum?

Answer 15

Between X-rays and visible light

Question 16

What happens atomically in UV lamps?

Answer 16

In lamps, UV photons excite (gives energy to) atoms. The atoms then release visible light

Question 17

What are the risks of UV light?

Answer 17

Exposure to too much ultraviolet light can cause skin burns, skin cancer and cataract formations in the eye.

Question 18

What is Ultraviolet light used for?

Answer 18

medical and forensic photography, air purification, disinfection and medical therapy and to detect fake bank not

Question 19

What are the risks of Infra-red radiation?

Answer 19

serious skin burns if emitted from high-intensity sources

Question 20

What is infra-red radiation used for?

Answer 20

TV controls, security purposes –> intruder alarms by detecting body heat.

Question 21

How is infra-red used to cook food?

Answer 21

The frequency is high enough to excite particles in food. This increases their temperature.

Question 22

What are microwaves used for?

Answer 22

Satellite communications, transmit signal from a nearby phone mast to a mobile phone.

Question 23

Why are microwaves useful for cooking food?

Answer 23

Microwaves are absorbed by water, heating up the water in the process. This makes microwaves useful for cooking food because food contains lots of water.

Question 24

How to microwaves travel through the atmosphere?

Answer 24

In straight lines. This makes them good for transmitting signals.

Question 25

Microwaves have a high enough frequency to…

Answer 25

penetrate the Earth’s atmosphere and to reach satellites.

Question 26

Why are microwaves dangerous to humans?

Answer 26

Humans are largely made up of water, exposure to microwaves could have a harmful effect.

Question 27

What safety precautions can we take to reduce any exposure to microwaves?

Answer 27

Always have some sort of shielding between the source of microwaves and living tissue.
An example of this is the protective shielding on microwave ovens.

Question 28

What are radio waves used for?

Answer 28

RAdio waves are used for radio and TV communications.

Question 29

Radio waves have ____ wavelengths?

Answer 29

Long, they can therefore be sent around the Earth’s surface and around buildings without interference.

Question 30

Why are radio waves potentially harmful?

Answer 30

At high intensities, radio waves can cause internal heating of living tissue.

Question 31

How can electromagnetic waves be produced?

Answer 31

By electrical circuits and by changes in atoms.

Question 32

How do gamma rays originate?

Answer 32

From changes in the nucleus of an atom

Question 33

What is visible light used for?

Answer 33

To see the world around and in fibre optics

Question 34

Why do we use visible light in optical fibres?

Answer 34

because it can be totally internally reflected. This means that we can transmit signals along optical fibres without the signal getting lost.

Question 35

If an object reflects all wavelengths equally, what colour is the object?

Answer 35

White