P12 Wave Properties (paper 2) Flashcards
1
Q
Define waves
A
Waves transfer energy with out transferring matter
2
Q
What are all waves casued by
A
oscillating particles
3
Q
What is the equation for frequency
A
Frequency = velocity / wavelength
4
Q
What are transverse waves
A
Waves where the particles oscillate perpendicular to the direction of energy transfer
5
Q
What direction are transverse waves
A
Up and Down
6
Q
What are examples of transverse waves
A
- tidal wave
- electromagnetic wave
- Seismic S wave
7
Q
What is a
A
wavelength
8
Q
what is b
A
peak or creast
9
Q
what is c
A
trough
10
Q
what is d
A
amplitude
11
Q
what is e
A
direction of energy transfer
12
Q
what is f
A
direction of oscillations
13
Q
What are logitudinal waves
A
Waves where the particles oscillate parallel to the direction of energy
14
Q
what direction are the osscillations of a logitudinal wave
A
forward and backward / side to side
15
Q
What are examples of logitudinal waves
A
- sound waves
- ultra-sound waves
- seismic P waves
16
Q
what is a
A
wavelength
17
Q
what is b
A
amplitude
18
Q
what is c
A
rarefaction
19
Q
what is d
A
compression
20
Q
what is e
A
direction of energy transfer
21
Q
what is f
A
direction of oscillation
22
Q
When does sound travel fastest and why
A
in solids becuase the particles are closer together so the vibraions are easily transfered
23
Q
Do sound waves need a medium to travel through and why
A
yes becuase in a vacuum there are no particles to transfer energy to
24
Q
What are the two methods to measure the speed of time
A
- clap-echo method
- microphones and data-logger method
25
what is the boundary for sound
20Hz - 20,000Hz
26
what is the boundary for ultra-sound
20,000Hz +
27
what is the boundary for infrasound
>20Hz
28
What are the uses of ultrasound
- clean jewelery
- pre-natal scan
- detect cracks inside metal structures
- detect is gold is real
29
what is the equation for distance
distance = speed x time
30
explain the method of the clap-echo method
- stand 50m away from a wall
- measure the time taken for a clap to echo from the wall
- speed = (distance / time)/2
31
explain the microphone and data-logger method
- you have 2 microphones and 1 data-logger
- data-logger measure and records time taken for sound to reach the microphones
- speed = distance/time
32
What are the benefits of the microphones and data-logger method
- higher resolution and therefore more accuracy
- no chance for human error
33
What is the equation relating time period and frequency
time period = 1 / frequency
34
What do you use to measure the speed of sound
oscilloscope
35
Can all waves be reflected
yes
36
What are the three things that can happen when a wave arrives at a boundary
- absorbed by the material
- trasmittedd through the material [leading to refraction]
- reflected off the material
37
how does the angle of incidence relate to the angle of reflection
angle of incidence = angle of reflection
38
what is the angle of incidence
the angle between the incoming wave and the normal
39
what is the angle of reflection
the angle between the reflected wave and the normal
40
What is the normal
an invisable line that is perpendicular to the surface at the point of incidence
41
What is a
the normal
42
what is b
the reflected ray
43
what is c
the incoming ray
44
What is d
the angle of incidence
45
what is e
the angle of reflection
46
What are the two different way waves can be reflected
- specular
- diffuse
47
what is specular reflection
when a wave is reflected in a single direction by a smooth surface
48
what is diffuse reflection
when a wave is reflected by a rough surface and the reflected rays are scatted in lots of different directions
49
What types of waves are electromagnetic waves
transverse
50
What is refraction
when a wave crosses a boundary between materials at an angle and it changes direction because it changes speed
51
What will happen to a wave if it crosses a boundary and slows down
it will bend towards the normal
52
what will hapen is the wave crosses into a material and speeds up
the wave will bend away from the normal
53
What happens to the wave physically when it is refracted
- the wavelength changes but the frequency stays the same so the waves speed up when the wavelength grows etc
54
if the wave is travelling along the normal will it refract
no but it will chnage speed
55
if the optial density is higher in a material then how does speed of the wave change
it will get slower
56
how do the angle of incidence and the angle of refraction relate
angle of incidence > angle of refraction
57
How do we measure the layers of the earth
with Seismic waves
58
What are the two types of seismic waves
- primary waves
- secondary waves
59
what are seismic waves
the energy transferred when forces inside the earth increas and become strong enough to break rock
60
what are P-waves
they are logitudinal waves that cause intitial termours that are refracted when they enter the outer core
61
what are S-waves
they are transverse waves that cannot travel through the outer core
62
what happens when seismic waves travel through the mantle
- bend
- speed changes gradually ewith depth
- therefore so does direction
63
What is the shadow zone
a zone where no P or S waves are recorded becuase P waves are refracted and S waves cannot travel through liquid
64
How do you convert something to a milli (m)
x1,000
x10^3
65
How do you convert something to a micro (μ)
x1,000,000
x10^6
66
how do you convert something to a kilo (k)
/1,000
x10^-3
67
How do you convert something to a mega (M)
/1,000,000
x10^-6
68
How do you convert something to a giga (G)
x1,000,000,000
x10^-9
69
If the refracted index is lower with the wave speed up or slow down
speed up
70
What angle must the angle of incidence be between
0 - 90 degrees
71
describe how ultrasound is used in pre-natal scans
- the ultrasound waves pass through the body
- they reach the boundary between the fuild in the womb and the feotus' skin
- wave is reflected and detected and then processed by a computer
- an image is created
