7.1GeneralWaveProperties1.notebook

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7.1GeneralWaveProperties

Whatisawave?

Awaveisanoscillationthatmovesthroughspace,transferringenergyfromoneplacetoanother.

Wave1.mp4

Water(themedium)ismovedupanddown,butisnotmovedinthedirectionofthewave.

Whichoftheseisnotanexampleofawave?

Alltruewavesmoveorpropagatethroughspace,thereforetheripplesonasanddunearenotwaves.

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7.1GeneralWaveProperties

Vibration Awaveisaperiodicdisturbanceinamaterial(medium)orspace.

Eachparticleofthemediumvibrates,oroscillates,aboutafixedposition.Energyistransferredoutwardsfromthesourceofthewave.

Wavesthatmoveoutwardsfromtheirsourcearecalledtravellingwaves.Thetwotypesofprogressivewavearetransverseandlongitudinal.

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7.1GeneralWavePropertiesWaveCharacteristics

Period

Amplitude

A

Wavelength

WavelengthThedistancebetween2consecutivepointsinphase

FrequencyThenumberofcyclesofthewavepersecond.Thebiggerthe

frequencythehigherthepitchofthenoteorthebluerthelight

AmplitudeThemaximumdistancethatanypointonthewavemovesfrom

itsmeanposition.Thebiggertheamplitudethelouderthesound,therougherthesea,orthebrighterthelight

Period(T)Thetimeittakesforonecompletecycleofthewave.

Displacement(x)Howfartheparticlehastravelledfromitsmeanposition.

Wavespeed(v)Thespeedatwhichthewavefrontspassastationaryobserver

Frequencyf=1/T

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Wavesintimeandspace7.1GeneralWaveProperties

Thesetwowaveformslookthesame,buttheyeachgivedifferentinformationaboutthewavetheyrepresent.

Thisgraphrepresentshowychangeswithtime.Itcouldbeanoscillationofvoltage,displacement,pressure,oranyothersuitablevariable,dependingonthecontext.

Thisgraphrepresentshowychangesalonganaxisxinspace.Itcouldbeawaveofdisplacementorpressure,oranyothersuitablevariable,dependingonthecontext.

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7.1GeneralWavePropertiesTheSpeedofaWaveThesewavesaretravellingacrossthesurfaceofapond.Thelengthofeachwaveis0.25m.

Twowavespasstheduckeachsecond,sothefrequencyis2Hz.

Thismeansthatthewavestravel0.5meachsecond,sothespeedofthewavesis0.5m/s.

speed=frequencywavelength0.5m/s=2Hz 0.25m

v=f

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7.1GeneralWavePropertiesElectromagnetic(EM)WavesElectromagneticwavestravelat300,000,000m/s(3x108m/s)throughavacuum.Thisvalueisapproximatelytheirspeedthroughair.

Atypicalradiostationmaybroadcastatafrequencyof98MHz.Calculatethewavelengthofthisradiowave.

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Transversevs.longitudinalwaves

7.1GeneralWaveProperties

Transversewavesarewhenthedisplacementisatrightanglestothedirectionofthewave

Longitudinalwavesarewhenthedisplacementisparalleltothedirectionofthewave

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7.1GeneralWaveProperties

Waveswillalwaysreflectinsuchawaythattheangleatwhichtheyapproachabarrierequalstheangleatwhichtheyreflectoffthebarrier.

LawofReflection

LawofRefraction

Refractionisaccompaniedbyachangeinspeedandwavelengthofthewaves.

Diffraction

Diffractionisthespreadingoutofawave.

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7.1GeneralWaveProperties

Homework

Page125#1HandoutQuestionsPage127#1&2

Attachments

Wave1.mp4

SMART Notebook

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