Waves

Level 3 Physics Study!

when waves are produced from a _______ source, f is the same at the detector and at the source

stationary

f is the same for the detector and at the source if there is no _______ _______ between the two

relative motion

when a sound wave is produced, it spreads out in all directions in _______ circles

concentric

when detected in front of a moving source, v_w _______ (increases / decreases / stays the same)

stays the same

when detected behind a moving source, v_w _______ (increases / decreases / stays the same)

stays the same

when detected in front of a moving source, f _______ (increases / decreases / stays the same)

increases

when detected in front of a moving source, λ _______ (increases / decreases / stays the same)

decreases

when detected behind a moving source, λ _______ (increases / decreases / stays the same)

increases

when detected behind a moving source, v_w _______ (increases / decreases / stays the same)

stays the same

when detected behind a moving source, f _______ (increases / decreases / stays the same)

decreases

the _______ effect explains that when a source _______ while producing waves, it will move closer to the _______ during the time waves are _______ out, so crests arrive _______ together and the observed wavelength is _______

doppler, approaches, detector, spreading, closer, shorter

the _______ of the wave is a property of the _______ so stays the same, even for a moving source

velocity, medium

when detected in front of a moving source, the _______ frequency is _______ than the _______ frequency

observed, higher, generated

the doppler shift calculation is used to measure the _______ velocity of the source and reciever

f’ = f × v_w / (v_w ± v_s)

relative

f’ = f × v_w / (v_w ± v_s), where…

• f’ is the apparent _______ to the _______

• f is the _______ frequency

• v_w is the velocity of the _______

• v_s is the velocity of the _______

frequency, detector, original, wave, source

when the source is receding, f’ __ f, so v_w and v_s must be _______ for a _______ denominator

f’ = f × v_w / (v_w ± v_s)

<, added, large

when the source is approaching, f’ __ f, so v_w and v_s must be _______ for a _______ denominator

f’ = f × v_w / (v_w ± v_s)

>, subtracted, smaller

when a source is directly approaching, there is _______ (greatest / lower) relative _______ between the source and _______ due to the _______ (perpendicular / parallel) motion

greatest, velocity, detector, perpendicular

when a source is directly approaching, the change from approaching to receiving occurs _______ (instantaneously / gradually)

instantaneously

when a source is approaching at an angle, there is _______ (greatest / lower) relative _______ between the source and _______ due to the component of _______ (perpendicular / parallel) motion

lower, velocity, detector, parallel

when a source is approaching at an angle, the change from approaching to receiving occurs _______ (instantaneously / gradually)

gradually

_______ occur for an observer when 2 waves with slightly different _______ arrive

beats, frequencies

when beats occur, the _______ of each wave adds to form the _______ wave

displacement, resultant

when beats occur, waves travel through the same _______ and therefore at the same _______, so there is no _______ movement between the waves

medium, velocity, relative

a large amplitude makes a _______ sound

loud

a small amplitude makes a _______ sound

quiet

the beat _______ is how rapidly the _______ amplitude _______

frequency, resultant, varies

f_beat is the _______ (sum / difference) of the frequencies of the contributing waves, because the closer the frequencies of each contributing wave are, the _______ (more / fewer) times they will be in phase per second

difference, fewer

T is the _______ over which the _______ of a beat varies from quiet to loud to quiet

T = 1 / f

period, amplitude

if a mass is added onto a tuning fork, this makes it _______ (harder / easier) for the fork to vibrate, since rotational inertia, __, _______, therefore the amplitude, __, _______ and the frequency, __, _______

harder, I, increases, A, decreases, f, decreases

if a mass is added onto the _______ of a tuning fork, the change in sound is small

bottom

if a mass is added onto the _______ of a tuning fork, the change in sound is significant

top

a _______ wave is created when two waves travel in _______ directions with the same f_______, a_______ and w_______; or when a single wave is _______ at a _______

standing, opposite, frequency, amplitude, wavelength, reflected, boundary

each position in a standing waves vibrates at a _______ amplitude, which is _______ from the amplitudes at positions around it

constant, different

the resulting wavefront of a standing wave appears _______

stationary

in a travelling wave, each particle along the wave vibrates with _______ (the same / a different) amplitude; in a standing wave, each particle along the wave vibrates with _______ (the same / a different) amplitude

the same, a different

within each _______ _______ _______, all positions along a standing wave vibrate _______

half wave envelope, in phase

unlike a standing wave, each position in a travelling wave vibrates _______ with that alongside it

out of phase

_______ positions along a standing wave are where the medium vibrates at maximum amplitude, which is the _______ of the amplitudes of the two contributing waves

antinodal

_______ positions along a standing wave are where there is no movement of the medium as the two contributing waves _______ _______

nodal, cancel out

the two contributing waves _______ with each other to create regions of maximum displacement, _______, and minimum displacement, _______

interfere, antinodes, nodes

a crest reflects from an open boundary as a _______

crest

a crest reflects from a closed boundary as a _______

trough

a string has _______ at either end, since they are both anchored and cannot move

nodes

the _______ wave is the standing wave created with the longest _______ and the lowest _______

fundamental, wavelength, frequency

in a/an _______ pipe, air is free to vibrate at either end so they are _______

open, antinodes

in a/an _______ pipe, air is free to vibrate at one end which forms a/an _______, and one end prevents vibrations which forms a/an _______

closed, antinodes, node

waves have to reflect _______ as far to fit within a _______ pipe, as the requirement for a node at one end and an antinode at the other severely _______ the standing wave shapes possible

twice, closed, restricted

only certain _______ fit in strings and pipe to set up standing waves, as the _______ of the generated wave must be consistent with v = fλ at a _______ frequency

wavelengths, frequency, resonant

a standing wave is the _______ of all _______ travelling back and forth through each other due to _______ at each end, rather than the sum of just __ waves, meaning its _______ is much larger

sum, waves, reflection, 2, amplitude

the 1st _______ is the next longest wavelength after the fundamental, and is equal to the 2nd _______

overtone, harmonic

the 1st _______ is equal to the fundamental

harmonic

the _______ of each harmonic is a _______ of that of the fundamental, meaning that the _______ is _______ proportional to the multiple of that of the harmonic

frequency, multiple, wavelength, inversely

for the 1st harmonic in a string and open pipe, λ = __L / __

2, 1

for the 2nd harmonic in a string and open pipe, λ = __L / __

2, 2

for the 3rd harmonic in a string and open pipe, λ = __L / __

2, 3

for the 1st harmonic in a closed pipe, λ = __L / __

4, 1

for the 3rd harmonic in a closed pipe, λ = __L / __

4, 3

for the 5th harmonic in a closed pipe, λ = __L / __

4, 5

closed pipes only produce _______ harmonics

odd

when a string on a guitar is _______ in the _______, waves _______ to either end of the string and are _______. these then _______ each other and _______, creating a _______ wave.

the frequency of the _______ wave is one of the many possible _______ frequencies of the string, which depend on the _______ of the string and the _______ of the wave through it, to be consistent with v_w = fλ.

the lowest possible frequency is the _______, which corresponds to the _______ possible wave that can fit on the string. all standing waves are constrained by the fact that they must have a _______ on each end as these positions are _______, causing the wavelength of the standing wave to be __. all other possible standing waves have _______ that are _______ of the _______.

plucked, middle, travel, reflected, cross, superimpose, standing, standing, resonant, length, velocity, fundamental, longest, node, fixed, 2L, frequencies, multiples, fundamental

the resonant frequencies required to set up standing waves in a closed pipe are restricted by the requirement to have a _______ at one end and an _______ at the other. the _______ possible wavelength that can fit is the _______, which is __. the next longest standing wave has a wavelength of __ of this. even _______ of the _______ of the fundamental do not fit in the closed pipe to form standing waves, as they would not form a ________ at one end and an _______ at the other, so only odd _______ can exist as standing waves.

node, antinode, longest, fundamental, 4L, ⅓, multiples, frequency, node, antinode, harmonics

speed of sound in a _______ can be calculated using v = √(T / μ), where…

• T = _______ of the rope, or the _______ pulling on it

• μ = _______ per _______ _______

rope, tension, force, mass, unit, length

waves travel fastest in a rope when it is _______ (loose / tight) and has _______ (low / high) density

tight, low

_______ the density, or mass per unit length, of a rope increases the speed of a wave through it

decreasing

_______ the tension of a rope increases the speed of a wave through it

increasing

speed of sound through any _______ can be calculated using v = √(B / ρ), where…

• B = _______ _______ of the medium

• ρ = _______ per _______ _______

medium, bulk modulus, mass, unit, volume

the bulk modulus of a medium measures how hard it is to _______ it; the tension is a rope measures how hard it is to s_______/d_______ it

compress, stretch, displace

a _______ wave must first be produced to set up a _______ wave

travelling, standing

travelling waves of different resonant frequencies are all _______ set up in a string/pipe

simultaneously

f of the resultant standing wave in a musical instrument determines _______, and is equal to that of the _______ wave, since λ_resultant = λ_fundamental

pitch, fundamental

the shape of the resultant wave determines the _______, or sound

timbre

the timbre depends on the _______ of overtones present and the _______ strengths, or _______, of these

number, relative, amplitudes

when 2 or more _______ waves of the same t_______ and f_______ are produced only a few _______ apart and travel through each other, waves _______

circular, type, frequency, wavelengths, interfere

constructive interference occurs when waves arrive _______ (in phase / out of phase), (_______)λ apart

in phase, n

destructive interference occurs when waves arrive _______ (in phase / out of phase), (_______)λ apart

out of phase, n + ½

constructive interference produces a/an _______

antinode

destructive interference produces a/an _______

node

for _______ interference, the crest and trough _______ out

destructive, cancel

for _______ interference, crests _______ to create a point/line of _______ displacement

constructive, add, maximum

the central antinodal line is labelled as __

0

2 waves are produced in phase if the _______ of the _______ is the same at either _______

displacement, medium, source

2 waves arrive in phase if, at that _______, they have the same changing _______ in the specific position

instant, displacement

if waves are produced out of phase, then a path difference of (n + ½)λ will causes waves to arrive _______

in phase

interference requires waves to be _______, where the behaviour of the _______ field of each source is the same and they are produced with a constant _______ _______

coherent, electromagnetic, phase difference

diffraction is the _______ out of waves as they pass through a narrow _______ or _______ around an obstacle

spreading, gap, spreading

interference requires waves to be _______, with the same _______

monochromatic, frequency

interference requires the _______ of each set of waves to be similar

amplitude

_______’s _______-slit experiment produces formulae to make diffraction calculations

young, double

to calculate the _______ between adjacent _______ _______, tanθ = x / L

angle, bright fringes

the small angle _______ can be used to equate θ to x / L, if θ is very _______ or __ is much smaller than __, resulting in the formula nλ = dx / L

approximation, small, d, L

the formula nλ = dx / L should only be used for _______, not _______

discussions, calculations

nλ = dsinθ and tanθ = x / L, where…

• n = _______ of bright fringes out from the _______ antinodal line

• d = distance between _______

• θ = angle from the _______ _______ _______

• x = distance between adjacent _______ _______

• L = distance from _______ to _______

number, central, slits, central bright fringe, bright fringes, slits, screen

the edges of the slits act as _______ _______

point sources

most light travels _______ through a slit, and _______ around the edges

straight, diffracts

a wider slit allows _______ light through so the fringe is _______

more, brighter

_______ _______ is there area either side of a bright fringe where two sources strike approximately in phase

partial reinforcement

a narrower slit causes more _______, so light strikes the screen more _______ in or out of _______, causing less _______ _______

diffraction, distinctly, phase, partial reinforcement

the _______ fringes and the most _______ occurs when d = λ

sharpest, diffraction

more slits causes more waves to be _______, which will strike the screen more _______ in or out of _______

interfering, distinctly, phase