ElectroMagnegnetic Waves

Question 1

Recite the electromagnetic spectrum in order of decreasing wavelength

Answer 1

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

Question 2

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

Answer 2

Radio waves

Question 3

What is the wave speed equation

Answer 3

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

Question 4

What do electromagnetic waves form

Answer 4

A continuous spectrum

Question 5

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

Answer 5

A vacuum (space)

Question 6

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

Answer 6

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

Question 7

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

Answer 7

White light contains all the colours of the physical spectrum

Question 8

What do we use infrared radiation for

Answer 8

Carrying signals from remote handsets and inside optical fibres

Question 9

What do we use microwaves for

Answer 9

Carrying satellite TV programmes and mobile phone calls

Question 10

What do we use radio waves for

Answer 10

Radio and TV broadcasting, radio communications and mobile phone calls

Question 11

What are the hazards of micro waves and radio waves

Answer 11

They can heat the internal parts of our bodies

Question 12

What is a danger with infrared radiation

Answer 12

Infrared radiation can cause skin burns

Question 13

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

Answer 13

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

Question 14

Are mobile phones safe to use?

Answer 14

Further research is needed to evaluate this

Question 15

What are optical fibres

Answer 15

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

Question 16

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

Answer 16

Ultraviolet radiation has a shorter wavelength than visible light

Question 17

What does ultraviolet radiation harm

Answer 17

The skin and the eyes

Question 18

What are x rays used for

Answer 18

To make x Ray images in hospitals

Question 19

What are gamma rays used for

Answer 19

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

Question 20

What and when do x rays and gamma rays damage

Answer 20

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

Question 21

What are x rays used for in hospitals

Answer 21

To make images and CT scans

To destroy tumours at or near the body surface

Question 22

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

Answer 22

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

Question 23

What do CT scans distinguish between

Answer 23

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

Question 24

What is the frequency range of the normal human ear

Answer 24

From about 20Hz to 20,000Hz

Question 25

What are sound waves

Answer 25

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

Question 26

What are echoes caused by

Answer 26

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

Question 27

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

Answer 27

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

Question 28

What increases the loudness of a sound

Answer 28

Increasing the amplitude of the sound wave

Question 29

What produces sound waves

Answer 29

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

Question 30

What are ultrasound waves

Answer 30

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

Question 31

What are ultrasound waves used for in medicine

Answer 31

Ultrasound scanning and destroying kidney stones

Question 32

When are ultrasound waves partly reflected

Answer 32

At a boundary between two different types of body tissue

Question 33

Why is an ultrasound scan safer than an x Ray

Answer 33

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