ElectroMagnegnetic Waves Flashcards Preview

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Flashcards in ElectroMagnegnetic Waves Deck (33):
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 is the wave speed equation

Wavelength (m) = speed (m/s) / frequency (Hz)

4

What do electromagnetic waves form

A continuous spectrum

5

All types of electromagnetic waves travel at the same speed through........

A vacuum (space)

6

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

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

7

........ Contains all the colours of the visible spectrum

White light contains all the colours of the physical spectrum

8

What do we use infrared radiation for

Carrying signals from remote handsets and inside optical fibres

9

What do we use microwaves for

Carrying satellite TV programmes and mobile phone calls

10

What do we use radio waves for

Radio and TV broadcasting, radio communications and mobile phone calls

11

What are the hazards of micro waves and radio waves

They can heat the internal parts of our bodies

12

What is a danger with infrared radiation

Infrared radiation can cause skin burns

13

Radio waves of different frequencies are used for different purposes because wavelength (and therefore frequency) of waves effect:

How far they can travel
How much they can spread
How much information they can carry

14

Are mobile phones safe to use?

Further research is needed to evaluate this

15

What are optical fibres

Optical fibres are very thin transparent fibres that are used to transmit signals by light and infrared radiation

16

Ultraviolet radiation has a ............. Wavelength than visible light

Ultraviolet radiation has a shorter wavelength than visible light

17

What does ultraviolet radiation harm

The skin and the eyes

18

What are x rays used for

To make x Ray images in hospitals

19

What are gamma rays used for

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

20

What and when do x rays and gamma rays damage

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

21

What are x rays used for in hospitals

To make images and CT scans
To destroy tumours at or near the body surface

22

X rays are absorbed more by........than by........

X rays are absorbed more by bones and teeth than by soft tissue

23

What do CT scans distinguish between

Different types of soft tissue as well as between bone (or teeth) and soft tissue

24

What is the frequency range of the normal human ear

From about 20Hz to 20,000Hz

25

What are sound waves

Sound waves are vibrations that travel through a medium (or substance). They cannot travel through a vacuum (outer space)

26

What are echoes caused by

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

27

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

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

28

What increases the loudness of a sound

Increasing the amplitude of the sound wave

29

What produces sound waves

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

30

What are ultrasound waves

Ultrasound waves are the sound waves of frequency above 20,000Hz

31

What are ultrasound waves used for in medicine

Ultrasound scanning and destroying kidney stones

32

When are ultrasound waves partly reflected

At a boundary between two different types of body tissue

33

Why is an ultrasound scan safer than an x Ray

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