Waves

Question 1

What is a wave

Answer 1

A way of transferring energy without transferring matter.

Question 2

What is a medium

Answer 2

The substance a wave travels through

Question 3

What happens to particles in a wave

Answer 3

They oscillate around a fixed position

Question 4

What is a transverse wave

Answer 4

Oscillations that are at right angles to energy transfer

Question 5

What is a longitudinal wave

Answer 5

Oscillations that are parallel to energy transfer

Question 6

Give an example of a longitudinal wave

Answer 6

sound

Question 7

Give examples of transverse waves

Answer 7

Light, water waves, electromagnetic waves

Question 8

What is a crest

Answer 8

The highest point of a wave.

Question 9

What is a trough

Answer 9

the lowest point of a wave

Question 11

What is amplitude

Answer 11

Height of wave from middle to top or bottom

Question 12

What is wavelength (λ)

Answer 12

Distance between two successive crests or troughs.

Question 13

What is frequency (f)

Answer 13

The number of waves passing a point each second

Question 15

What is the unit of frequency

Answer 15

Hertz (Hz)

Question 16

What does 1 Hz mean

Answer 16

1 wave per second

Question 17

What is period (T)?

Answer 17

Time taken for one complete wave to pass a fixed point

Question 18

What is wave speed (v)?

Answer 18

Distance a wave travelled per second

Question 19

Wave speed equation

Answer 19

v = fλ

Question 20

Speed equation

Answer 20

v = d / t

Question 21

Standard unit of time

Answer 21

Seconds (s)

Question 22

Standard unit of distance

Answer 22

Metres (m)

Question 23

Common prefixes

Answer 23

kilo (k) = 10³
milli (m) = 10⁻³
micro (µ) = 10⁻⁶
mega (M) = 10⁶

Question 24

Speed of sound in air

Answer 24

340 m/s

Question 25

Speed of light in vacuum

Answer 25

3 × 10⁸ m/s

Question 26

Do electromagnetic waves need a medium

Answer 26

No

Question 27

What is diffraction

Answer 27

Spreading of waves through a gap or around an obstacle

Question 28

When is diffraction greatest

Answer 28

When gap size ≈ wavelength

Question 29

Frequency equation

Answer 29

f = 1 / T

Question 30

Long vs short wavelength diffraction

Answer 30

Long wavelengths diffract more

Question 31

Order of EM spectrum (low → high frequency)?

Answer 31

Radio → Microwaves → Infrared → Visible → UV → X-rays → Gamma

Question 32

Wave equation for EM waves

Answer 32

v = fλ

Question 33

Relationship between frequency and wavelength

Answer 33

As frequency increases, wavelength decreases

Question 34

Relationship between energy and frequency

Answer 34

Energy is proportional frequency

Question 35

Speed of all EM waves

Answer 35

3 × 10⁸ m/s

Question 36

Gamma source

Answer 36

Radioactive materials

Question 37

Gamma detectors

Answer 37

Geiger muller tube/Photodiodes

Question 38

X ray source

Answer 38

X ray tube

Question 39

X ray detector

Answer 39

Photographic film/Photodiode

Question 40

Ultraviolet source

Answer 40

Sun/UV light

Question 41

Ultraviolet detector

Answer 41

Fluorescent materials

Question 42

Visible light source

Answer 42

Sun/lamp

Question 43

Visible light detector

Answer 43

Eye/ photographic film

Question 44

infrared source

Answer 44

hot objects

Question 45

infrared detector

Answer 45

Thermochromic film / black bulb thermometer / photodiode

Question 46

microwave source

Answer 46

Microwave transmitters / mobile phones

Question 47

microwave detector

Answer 47

aerial

Question 48

radio wave source

Answer 48

radio transmitter

Question 49

radio wave detector

Answer 49

aerial

Question 50

Gamma ray use

Answer 50

treat cancer

Question 51

X rays use

Answer 51

medical imaging

Question 52

UV use

Answer 52

Security marking / skin treatment

Question 53

infrared use

Answer 53

Heat detection / remote controls

Question 54

microwaves use

Answer 54

Cooking / communication

Question 55

Radio waves use

Answer 55

TV and radio signals

Question 56

What is the normal

Answer 56

Line at 90° to the surface

Question 57

Law of reflection

Answer 57

Angle of incidence = angle of reflection

Question 58

What is refraction

Answer 58

Change in direction and speed when light passes into a different medium

Question 59

What happens when light enters glass

Answer 59

Slows down, bends towards normal

Question 60

What happens when light leaves glass

Answer 60

Speeds up, bends away from normal

Question 61

Why does white light split

Answer 61

Different frequencies refract differently

Question 62

Which colour bends most

Answer 62

Violet

Question 63

Which colour bends least

Answer 63

Red

Question 64

Colour order

Answer 64

Red → Orange → Yellow → Green → Blue → Indigo → Violet

Question 65

what is reflection

Answer 65

the bouncing back of light when it hits a surface, into the same medium

Question 66

What changes in refraction

Answer 66

speed and direction

Question 67

When does refraction happen

Answer 67

When light crosses between different materials (e.g. air → water)

Question 68

What stays the same in reflection

Answer 68

Light stays in the same medium (no change in speed).