Waves Flashcards
(43 cards)
1
Q
What is the amplitude?
A
- The maximum displacement of the wave from its rest position
2
Q
What is the wavelength?
A
- The distance from one point in the wave to the identical point on the next wave
- Crest to crest or compression to compression
3
Q
What is the frequency?
A
- The number of complete wave cycles passing a point in one second
- Measured in Hz
4
Q
What is the period?
A
- The time it takes for a wave to travel on wavelength
5
Q
What is the equation for wave speed?
A
v = fλ
6
Q
What is the equation for frequency?
A
frequency = 1/time period
7
Q
What is rarefraction?
A
- Points on a longitudinal wave where particles are spread out most
8
Q
What is compression?
A
- Points on a longitudinal wave where particles are bunched together the most
9
Q
What is a wave?
A
- The transfer of energy and information using vibrations without transferring matter
10
Q
What is a transverse wave?
A
- A wave where the particles oscillates perpendicular to the direction of travel of the wave
11
Q
What is a longitudinal wave?
A
- A wave where the particles oscillates parallel to the direction of travel of the wave
12
Q
Examples of transverse waves?
A
- Water waves
- Wave on a string (musical instrument)
- Electromagnetic waves
13
Q
Examples of longitudinal waves?
A
- Sound
14
Q
What is the speed of all electromagnetic waves in a vacuum?
A
- 3 x 10^8 m/s
15
Q
What is the normal?
A
- The line perpendicular to the surface
16
Q
What is the angle of incidence?
A
- Angle between the incident ray and the normal to the surface
17
Q
What is the angle of reflection?
A
- Angle between the reflected ray and the normal to the surface
18
Q
What is the angle of refraction?
A
- Angle between the refracted ray and the normal to the surface
19
Q
What is the incident ray?
A
- Ray from object going towards the mirror/boundary
20
Q
What is the reflected ray?
A
- Ray coming away from the mirror or boundary
21
Q
What is refraction?
A
- When a wave changes in direction caused by changing speed
- Moving from one medium to another
22
Q
When a wave speeds up (e.g. from glass to air), the refracted ray bends ___ from the normal.
A
AWAY
23
Q
When a wave slows down (e.g. form air to glass), the refracted ray bends ___ from the normal.
A
TOWARDS
24
Q
What electromagnetic waves can our eyes detect?
A
- Visible light
25
What are the seven different types of EM radiation from biggest wavelength to smallest wavelength?
- Radio
- Microwaves
- Infrared
- Visible Light
- Ultraviolet
- X-ray
- Gamma
26
What are the uses and dangers of radio waves?
- TV
- Radio
- No known danger
27
What are the uses and dangers of microwaves?
- Satellite communications
- Cooking food
- Possible heat damage to internal organs
28
What are the uses and dangers of infrared radiation?
- Electrical heaters
- Cooking food
- Infrared cameras
- Skin burns
29
What are the uses and dangers of visible light?
- Fibre optic communications
- Bright light can cause eye damage
30
What are the uses and dangers of ultraviolet radiation?
- Energy efficient lamps
- Sun Tanning
- Eye damage
- Sunburn
- Skin cancer
31
What are the uses and dangers of X-rays and gamma rays?
- Medical imaging
- Cancer treatments because of ionising ability
- Kills (healthy) cells
- Mutations
- Cancer
32
What are the three types of ionising waves in the EM spectrum?
- Gamma
- X-ray
- Ultraviolet
33
What is the range of human hearing?
- 20-20,000 Hz
34
What is an oscilloscope?
- A piece of equipment that displays a graph of how vibrations oscillate with time
35
How do you change the pitch of a wave?
- Higher if frequency increases
36
How do you change the volume of a wave?
- Louder if amplitude increases
37
What is the law of reflection?
- Angle of incidence = angle of reflection
38
What is the critical angle?
- Angle of incidence gives an angle of refraction of 90 degrees (goes along the surface on a diagram)
39
What is Snell's law?
- At the boundary between two given materials, n1 sin(i) = n2 sin(r)
-
40
What is the refractive index?
- Ratio between speed of light in a vacuum to speed of light in a medium
- n = sin(i)/sin(r) (less dense to more dense reverse if else)
- ALWAYS >= 1
41
Refractive index at critical angle?
- n = 1/sin(c)
42
What condition must happen for total internal reflection to occur?
- Incident ray > critical angle
43
What is the doppler effect?
- The APPARENT change in frequency of wave caused by the relative motion between the source of the wave or the observer
- Source moving towards = higher pitch and lower wavelength
- Source away = lower pitch and higher wavelength
