ElectroMagnegnetic Waves COPY Flashcards Preview

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Flashcards in ElectroMagnegnetic Waves COPY Deck (40):
1

Recite the electromagnetic spectrum in order of decreasing wavelength

Radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, x rays and gamma rays

2

What type of wave has the lowest frequency and energy, but largest wavelength

Radio waves

3

What do electromagnetic waves form

A continuous spectrum

4

Where do all types of electromagnetic waves travel at the same speed

All types of electromagnetic waves travel at the same speed through a vacuum (space)

5

What is the range of the wavelengths of the electromagnetic spectrum?

From 10^(-15) to 10^(4) metres

6

What type of light contains all the colours of the visible spectrum

White light contains all the colours of the physical spectrum

7

What do we use infrared radiation for

Carrying signals from remote handsets and inside optical fibres

8

What do we use microwaves for

Carrying satellite TV programmes and mobile phone calls

9

What do we use radio waves for

Radio and TV broadcasting, bluetooth

10

What is a danger with infrared radiation

Exposure can cause skin burns

11

What can exposure to ultraviolet cause

Skin cancer and blindness

12

What are x rays used for

Medical imaging

13

What are gamma rays used for

To kill harmful bacteria in food, to sterilise surgical equipment and to kill cancer cells

14

What and when do x rays and gamma rays damage

X rays and gamma rays damage living tissue when they pass through it

15

What are x rays used for in hospitals

To diagnose some medical conditions, for examiner in computed tomography (CT) scanning, bone fractures and dental problems. X rays are also used to treat some conditions, for example in killing cancer cells

16

What do CT scans distinguish between and how does this happen

Different types of soft tissue as well as between bone (or teeth) and soft tissue. This is because X rays are absorbed more by bones and teeth than by soft tissue

17

What is the frequency range of the normal human ear

From about 20Hz to 20,000Hz

18

What are sound waves

Sound waves are longitudinal waves and cause vibrations in a medium, which are detected as sound. They can be reflected (echoes) and diffracted

19

What are echoes caused by

Echoes are caused by sound waves reflected from a smooth, hard surface

20

The pitch of a note increases if the ............ Increases

The pitch of a note increases of the frequency of the sound waves increases

21

What increases the loudness of a sound

Increasing the amplitude of the sound wave

22

What produces sound waves

Vibrations created in a musical instrument when it is played produce sound waves

23

What is ultrasound

Ultrasound is acoustic (sound) energy, in the form of waves with a frequency above the human hearing range (20,000Hz)

24

What are ultrasound waves used for in medicine

Pre-natal scanning and the removal of kidney stones

25

What happens when ultrasound waves meet a boundary between two different media

Ultrasound waves are partially reflected when they meet a boundary between two different media

26

Why is an ultrasound scan safer than an x Ray

An ultrasound scan is non ionising, so it is safer than an X-ray

27

What type of wave has the smallest wavelength

Gamma rays

28

What types of waves can be used for communication

Radio waves, microwaves, infrared and visible light

29

Whats the hazard of exposure to microwaves

Heating of body tissue

30

What is a use of visible light

Photography

31

What is a use of ultraviolet

Security marking

32

What is the hazard of exposure to X rays

High doses kill cells

33

What can exposure to gamma rays cause

Genetic mutations

34

Characteristics of X rays

They have a very short wavelength, high energy and cause ionisation

35

What do properties of X rays include

-They affect a photographic film in the same way as light -They are absorbed by metal and bone -They are transmitted by soft tissue

36

What are the problems with the use of high energy ionising radiation, and what precautions therefore need to be taken

The use of high energy ionising radiation can be dangerous, and precautions need to be taken to monitor and minimise the levels of radiation that people who work with it are exposed to

37

How can you use ultrasound to determine how far away a boundary is

Ultrasound waves are partially reflected when they meet a boundary between two different media. They time taken for the reflections to reach a detector can be used to determine how far away such a boundary is (distance = [wave] speed x time)

38

What is the pitch of a sound determined by

Its frequency

39

What is the loudness of a sound determined by

Its amplitude

40

What can be used to produce ultrasound waves

Electronic systems