Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

physics > p12 - waves > Flashcards

p12 - waves Flashcards

You may prefer our related Brainscape-certified flashcards:
Physics 101 flashcards AP® Physics flashcards
1
Q

two different types of waves

A

transverse and longitudinal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what do waves transfer?

A

energy (not matter)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what causes waves?

A

vibrations and oscillations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

transverse waves

A

when the displacement is at right angles (up and down) to the direction of the wave (horizontally) so they cross at a perpendicular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

longitudinal waves

A

when the direction of energy transfer is parallel to the direction of the wave

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

examples of transverse waves

A

UV, electromagnetic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is it called when longitudinal waves are close together?

A

compressions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is it called when longitudinal waves are further apart?

A

rarefactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

wavelength

A
  • lambda
  • the distance between two identical points on the wave
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

frequency

A
  • hertz
  • the number of waves per second
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

1 wave per second =

A

1 hertz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

amplitude

A

the maximum displacement from the rest position/equilibrium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

equation for frequency

A

number of waves/time(s)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

wave equation

A

wave speed (m/s) = frequency (Hz) x wavelength (m)
v = fA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

1 hertz =

A

1/second

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

time period

A

time needed for the wave to complete one full vibration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

equation for period

A

period (s) = 1/ frequency (Hz)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

speed of sound:

A

330 m/s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

calculating frequency (period equation)

A

frequency (Hz) = 1/period (s)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

reflected

A
  • waves will reflect off a flat surface
  • the smoother the surface, the stronger the reflected wave is
  • rough surfaces scatter the light in all directions, so they appear matt and not reflective.
  • angle of incidence = angle of reflection
  • light will reflect if the object is opaque and is not absorbed by the material
    > the electrons will absorb the light energy, then reemit it as a reflected wave
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

transmitted

A
  • waves will pass through a transparent material
  • the more transparent, the more light will pass through the material
  • it can still refract, but the process of passing through the material and still emerging is
    transmission
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

specular reflection

A

type of reflection we get from smooth, shiny surfaces

23
Q

diffuse reflection

A

type of reflection we get from rough, matt surfaces

24
Q

REQUIRED PRACTICAL: how does increasing the angle of incidence affect the ray of reflection?

A
25
Q

three things that can happen when a wave meets an interface of a material

A

refection, refraction or transmission

26
Q

what is the ray going into a mirror called?

A

incident ray

27
Q

name of the angle to the normal before it is reflected

A

angle of incidence

28
Q

law of reflection

A

angle of incidence = angle of reflection

29
Q

refraction

A

when waves are transmitted from one medium to another and there’s a difference in the optical density of the two media
- only occurs if the wave approaches the light at an angle
- if the wave approaches straight on (along the normal) the wave may change speed but NOT direction

30
Q

optically dense

A
31
Q

normal

A
32
Q

wave fronts

A
33
Q

if it’s going from less optically dense to MORE optically dense:

A

the light will bend towards the normal (refracts more)

34
Q

if the light is going from a more optically dense material to a LESS optically dense material:

A

then it bends the other way (away from normal)

35
Q

REQUIRED PRACTICAL: investigating the refraction of light

A
36
Q

speed of sound

A
37
Q

human hearing range

A

20Hz - 20,000Hz

38
Q

what are sounds above the human hearing range classified as?

A

ultrasound

39
Q

ultrasound

A
40
Q

what can happen when waves arrive at a boundary/material?

A
  • reflected or partially reflected
  • transmitted
  • absorbed
  • refracted
41
Q

two common purposes for waves

A
  • ultrasound
  • seismic waves
42
Q

when are soundwaves partially reflected?

A

when an ultrasound wave meets a boundary between two different materials

43
Q

pulse of an ultrasound

A

when directed at an object, some of the wave is reflected back

44
Q

uses of ultrasound

A
  • medical imaging
  • industrial imaging
  • echo sounding
45
Q

ultrasound in industrial imaging

A
  • ultrasound waves enter the material
  • usually then partially reflected back by the far side of the material
  • if there’s a crack inside the material then it will be reflected sooner, indicating a flaw
  • the depth of each feature of a flaw can be calculated using s = vt, which allows us to form an image of the flaw
46
Q

ultrasound in medical imaging (pre-natal scanning of a foetus)

A
  • ultrasound waves enter and pass through the body
  • some of the wave is reflected back (echoes) each time it meets a boundary (PARTIAL REFLECTION)
  • reflections from different boundaries at different depths return at different times
  • the depth (distance) of each structure/boundary can be calculated using s = vt and can be used to construct an image
47
Q

why is a gel added?

A

to avoid the ultrasound wave being reflected back at the skin surface, a gel is placed between the patient’s skin and the ultrasound probe

48
Q

seismic waves

A
  • shock waves that are produced whenever there is an earthquake
  • can be detected using a seismometer
49
Q

two different types of seismic waves

A

S-waves and P-waves

50
Q

primary waves (P-waves)

A
  • longitudinal waves
  • can travel through solids and liquids and can therefore pass through all of the earth’s layers
  • the density of the earth increases with depth so as the waves pass through the earth, they change speed and refract gradually
  • when the waves experiences dramatic changes in the earth’s structure there is also a dramatic refraction of the wave
51
Q

secondary waves (S-waves)

A
  • transverse waves
  • can ONLY travel through solids, so can’t pass through all layers of earth
  • they are SLOWER than p-waves
  • the density of the earth increases with depth, so as the s- waves pass through the mantle, they change speed and gradually refract
52
Q

importance of seismic waves

A
  • allow scientists to determine where the properties of the earth change dramatically
  • helps comprehend the internal structure of the earth (depending on where there is a major refraction)
53
Q

comparing p-waves and s-waves

A

P-waves are longitudinal whilst S-waves are transverse

P-waves can go through both solids and liquids but S- waves can only go through solids (the earth’s mantle) therefore they are much slower

Therefore p-waves can travel through all internal structures of the earth while s-waves are absorbed once they travel through the liquid

Both types of waves gradually refract when they encounter a dramatic change in the earth’s structure

Both are seismic waves that are produced when there are earthquakes

physics (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions