P12: Electro Magnetic Waves

Question 1

What is the order of waves in the electromagnetic spectrum in order of increaing frequency?

Answer 1

Radio waves
Micro waves
Infrared radiation 
Visible light 
Ulta violet
X rays 
Gamma rays

Question 2

Can electromagnetic waves travel through a vaccum?

Answer 2

Yes

Question 3

What is the speed of all the electromagnetic waves?

Answer 3

3 x 10 to the power of 8

Question 4

How does the wavelength of visible light vary?

Answer 4

400nm-700nm

Question 5

What do electromagnetic waves transfer?

Answer 5

Hey transfer energy to a source to an absorber

Question 6

What is the wave speed equation?

Answer 6

Frequency x wavelength

Question 7

What is light from the sun called?

Answer 7

White light

Question 8

What does white light contain?

Answer 8

All the colours of the visibile spectrum

Question 9

How does the heat of an object affect the amount of infrared radiation it emits?

Answer 9

The hotter an object the more infrared infrared radiation it emits

Question 10

What can infrared radiation do to the body?

Answer 10

• it can be absorbed by the skin

- it can damage, burn or kill the cells because it heats them up

Question 11

What do optical fibres in communications systems usually do and why?

Answer 11

They usually use infrared radiation instead of visible light

This is because infrared radiation is absorbed less than visible light in glass fibres

Question 12

What are optical fibres

Answer 12

It is a flexible transparent filter made by drawing glass

Question 13

What are microwaves used for?

Answer 13

-to carry satellite TV programmes and mobile phone calls.

Question 14

What are radiowaves used for?

Answer 14

-radio and TV broadcasting, radio communications and mibile phone calls.

Question 15

What can ionising radiation do?

Answer 15

Makes uncharged atoms become charged

Question 16

How is ultraviolet waves harmful?

Answer 16

They can harm the skin and eyes

Question 17

What are gamma rays used for?

Answer 17

• kill bacteria in food
• sterilise surgical equiptment
• kill cancer cells

Question 18

What are x rays absorbed by?

Answer 18

More bones and teeth than soft tissues

Question 19

Whyare x-rays harmful because________

Answer 19

X rays are ionising radiation

Question 20

What are carrier waves?

Answer 20

Waves used to carry any type of signal

Question 21

What type of wave to carry signals does it depend on?

Answer 21

• how much info is in the signal

- how far the signal has to travel

Question 22

The shorter the wavelength of a wave

Answer 22

• the more info they carry
• the shorter their range(absorbed by the atmosphere(

-the less they spread out

Question 23

What are optical fibres

Answer 23

Very thin glass fibres, used to transmit singnals carried by light or infrared radiation

• light rays can’t escape the fibre, when they reach the surface they are reflected back
• optical fibres carry a lot more infomation as light has a shorter wavelength than radio waves

Question 24

What can ultraviolet waves do to the body?(3 answers)

Answer 24

• can cause blindness
• sun burn
• skin cancer

Question 25

What do gamma rays and x-rays have in common?(3answers)

Answer 25

- travel straight into and through substances if they are not to dense or thick - have short wavelengths - both carry a lot of energy per second

Question 26

What are the differances between x-rays and gamma rays?(3 ways)

Answer 26

- gamma rays have a shorter wavelength so they can penatrate some substances that x-rays can't - gamma raysbare produced by radioactive substances - x-rays are produced when electrons moving at high speeds are stopped

Question 27

Benifits of gamma rays(2 things):

Answer 27

- kill cancer cells | - kill harmful bacteria

Question 28

What is ionisation

Answer 28

X-rays and gamma rays pass througg substances and knock electrons out of an atom -atoms become charged because they lose electrons

Question 29

What happens if ionising radiation happens in a living cell?

Answer 29

The cell can be damaged or killed. Low doses of x-rays and gamma rays can cuase gene mutation and canerous growth

Question 30

X-rays can do what to help us?

Answer 30

- make images of internal body parts | - desteoy tumor near the body surface

Question 31

Xxrays are absorbed by

Answer 31

Bones and teeth more than soft tissue

Question 32

Radio waves have the highest______

Answer 32

Wavelength

Question 33

Gamma rays have the highest______

Answer 33

Frequency

Question 34

What is the equation for wave speed(m/s)?

Answer 34

Frequency(Hz) X wavelength (m)

Question 35

What is the speed of all the waves in the electromagnetic spectrum?

Answer 35

3 x 10 to the power of 8

Question 36

What is white light?

Answer 36

Light from the sun(it has all the colours of the visible spectrum in it)

Question 37

As the frequency of a wave increases………

Answer 37

Tne energy of a wave increases

Question 38

The hotter an object is………

Answer 38

The more radiation it emits

Question 39

How can infrared radiation harm the body?

Answer 39

-absorbed by the skin, it can damage burn or heat the skin cells because the cells are heated

Question 40

What divices are infrared radiation used in?(4answers)

Answer 40

- optical fibres - heaters - remote control - infrared cameras

Question 41

What are microwaves used for? (3 answers)

Answer 41

- satellite communications (because they can pass through the atmosphere) - carry mobile phone signals - microwave ovens heat food quickly

Question 42

What are radio waves used for?(2 answers)

Answer 42

- to carry TV,radio and mobile phone signals | - can be used instead of cables to connect a computer (Bluetooth)

Question 43

List the radiations in order of ionising power?

Answer 43

- alpha radiation-most ionising power - beta-2nd most ionising power - gamma-least ionising power

Question 44

What is Beta radiation stopped by?

Answer 44

A thin sheet of metal

Question 45

What is gamma radiation stopped by?

Answer 45

Thick lead(gamma radiation has an unlimited range in air)

Question 46

What is the range of alpha radiation in air?

Answer 46

A few cm

Question 47

What is the range of beta radiation in air?

Answer 47

1 metre

Question 48

What can ionising a living cell do?

Answer 48

Damage or kill the cell