waves Flashcards

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1
Q

what type of waves are p-waves

A

p-waves are longitudal

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2
Q

what type of waves are s-waves

A

s-waves are transverse

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3
Q

what is a progressive wave

A

an oscillation that travels through matter and transfers energy, not matter

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4
Q

what happens to particles when a progressive wave moves to a new mdian

A

they move from their original position to a new position

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5
Q

what happens to a displaced particle once a wave enters a nwe mdian

A

it experiences a restoring force from its neighbours that pull it back to its original position

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6
Q

what are peaks and troughs

A

this is when the oscillating particles are at a maximum displacement from their equillibrium position

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7
Q

what happens to particles as sound waves move through the air

A

air particles are displaced and bounce off their neighbours causing collisions which provide a restoring force

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8
Q

amplitude

A

maximum displacement from the equilibrium position

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9
Q

wavelength

A

minimum distance between two points in phase on adjacent waves

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10
Q

period

A

the time taken for one oscillation

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11
Q

frequency and period equation

A

f = 1/T

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12
Q

phase difference

A

phase difference describes the difference between the displacements of particles along a wave or the displacements of particles on different waves

measured in degrees or radians

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13
Q

what degree means particles are in antiphase

A

pi radians

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14
Q

equation for phase difference between two points on a wave

A

phi = (x(distance) / wavelength)*360

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15
Q

two types of graphs to show waves

A

-displacemet distance graphs
-displacement time graphs

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16
Q

what can be used to determine the frequency of a wave

A

oscilloscope

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17
Q

what does each horizontal square on an oscilloscope represent

A

timebase

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18
Q

what is reflection

A

reflection occurs when a wave changes direction at a boundery between two different media, while remaining in the same medium

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19
Q

law of angle of reflection

A

angle of incidence = angle of reflection

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20
Q

what is rarefraction

A

rarefraction occurs when a wave changes direction as it changes speed when it passes from one median to another

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21
Q

what happens when a rarefracted wave slows down

A

the wave bends towards the normal

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22
Q

what happens when a rarefracted wave speeds up

A

the wave bends away from the normal

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23
Q

what is affected when a wave rarefracts

A

wavelength and wave speed

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24
Q

what happens to the wavelength of a refracted wave when it speeds up

A

wavelength increases and vice versa

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25
Q

what is diffraction

A

the way a wave spreads out as it passes through a gap or goes around an obstacle

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26
Q

what changes when diffraction occurs

A

nothing, speed wavelength and frequency remain constant

27
Q

when are diffraction effects most significant

A

they are most significant when the size of the gap or obstacle is about the same as the wavelength of the wave.

28
Q

what is polarisation

A

polarisation is when a particle oscillates in one direction and is confined to a single plane

29
Q

when is a wave said to be plane polarised

A

when the wave is confined to a single plane and only oscillates in one direction

30
Q

can longitudinal waves be polarised

A

no as the oscillations are always confined to one plane

31
Q

what happens when a transverse wave frelects off a surface

A

they become partially polarised meaning there are more waves oscillating in one particular plane but the wave is not completelyt plane polarised

32
Q

instensity definition

A

the radiant power passing through a surface per unit area

33
Q

instensity equation

A

I = P/A

34
Q

relation between amplitude and intensity

A

intensity is directly proportional to (amplitude)^2

35
Q

what are EM waves

A

EM waves can be thought off as electric and magnetic fields oscillating at right angles to each pther

36
Q

how are gamma and x-rays identified in the overlap region

A

they are identified by their origin
x-rays are identified by fast moving electrons whearaas gamma rays come from unstable atomic nuclei

37
Q

refractive index

A

a material property that describes how the material affects the speed of light travelling through it

38
Q

refractive index equation

A

n = c/v

39
Q

two refraction law equations

A

nsin(theta) = K
n1sin1(theta) = n2sin2(theta)

40
Q

principle of superposition

A

when two waves meet at a point the resultant displacement at that point is equal to the sun=m of the displacemts of the original waves

41
Q

what is interferacne

A

when two progressive waves continously pass through each other they superpose and produce a resultant wave

42
Q

what is constructive interferance

A

when two waves are in phase there is maxiumum positive displacement from wach wave line up

43
Q

what is coherence

A

waves that are emitted from two sources and have a constant phase difference

44
Q

what do interference patterns contain a series off?

A

they contain a series of maxima and minima

45
Q

what happens at maxima in interference patterns

A

the waves interfere constructivley

46
Q

what happens at minima in interference patterns

A

the waves interfere destructivley

47
Q

what is path difference between two waves

A

the differnce between the distance travelled between two waves from their sources to a point

48
Q

what condition is needed for two coherent waves to arrive at a point in phase

A

they waves will arive in phase if the path differnce is 0 or a whole number of wavelengths. this results in constructive interfernce and a higher amplitude

49
Q

what condition is needed for two coherent waves to arrive at a point in antiphase

A

the waves will arive in antiphase if the pth difference to a point is an odd number of half wavelengths

50
Q

what light source must be used in youngs double slit experiment

A

monochromatic light so that only a specifc frequency of light can pass through

51
Q

explain the first bit of youngs

A

monochromatic light enters the first single slit. it diffracts and arrives at the double slit in phase. it diffracts again from the double slit which acts as a source of two coherent waves which spread from each slit, overlapping and forming an interfernce pattern that can be seen on the screen as a pattern off bright and dark regions called fringes

52
Q

what did youngs double slit show

A

the experiment displayed the wave nature of light

53
Q

one equation for youngs

A

wavelength = seperation between two slits*seperation between fringes / distance to the screen

54
Q

approx wavlength of radio

A

10^-1 to 10^6

55
Q

approx wavlength of micro

A

10^-3 to 10^-1

56
Q

approx wavelgnth of IR

A

(10^-7 to 10^-3)

57
Q

approx wavelength of visable light

A

(410^-7) to (710^-7)

58
Q

approx wavlength of uv

A

(10^-8) to (10^-7)

59
Q

approx wavlength of x-rays

A

10^-13 to 10^-8

60
Q

approx wavelength of gamma

A

10^-16 to 10^-10

61
Q

what is a stationary wave

A

a stationary wave is the superposition of two progressive waves with the same wavelength moving in opposite directions

62
Q

what differs between progressive waves and stationary

A

no energy is transmitted by a stationary wave

63
Q
A