Physics AS Revision Notes - Excluding materials

Ive condensed a couple of text books into a small booklet! Great for revision seeing as the exams are very close

If there is anything I could improve on, or change please comment and tell me!

I AM VERY SORRY FOR ANY SPELLING MISTAKES!!!

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  • Created by: arbi_h
  • Created on: 29-04-16 19:27
Preview of Physics AS Revision Notes - Excluding materials

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2016
PhysicsRevision
AS­REVISION(EXCLUDINGMATERIALS)
ARBI

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Waves
- Cycle=Onecompletevibrationofawave
- Displacement=Howfarapointonthewavehasmovedfromitsundisturbedposition
(metres)
- Amplitude=Maximummagnitudeofdisplacement
- Wavelength,=lengthofonewholewavecyclefromtwosimilarpoints
- Period(T),s=Timetakenforawholecycletocompleteortopassagivenpoint
- Frequency=Thenumberofcyclespersecondpassingagivenpoint
- Phase=Ameasurementofthepositionofacertainpointalongthewavecycle
- Phasedifference=Amountthatonewavelagsbehindanotheràmeasuredinangles
(degreesorradian)orasfractionsofacycle
- Reflection=Waveisbouncedwhenithitsaboundary
- Refraction=Wavechangeddirectionasitentersadifferentmediumàspeedingupor
slowingdown
- Frequencyistheinverseofperiod
#
- = f=frequency-T=period Units=1Hz=1s-1
$
- Speedofawave=wavelengthxfrequency
- = 3x108forlightinavacuum
- Longitudinalwavesvibratealongthedirectionofenergytransferàconsistsof
compressionsandrarefactionsofthemediumittravelsthrough(sound)
- TransversewavesvibrateatrightanglestothedirectionofenergytransferàallEM
wavesaretransverse
- Apolarisedwaveonlyvibratesinonedirectionàonlytransversewavesbehavelike
thissoproofthatEMaretransverse
- Polarisingfiltersonlytransmitvibrationsinonedirection…read more

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Polarisingglassesusesthiseffect
àblocksunwantedglareatacertain
angle
TelevisionandRadiosignalsarepolarised
- Aerialrodsarehorizontalsotheylineupwiththereceivingaerialotherwisethe
strengthofthesignalwillbelower
- Sameforradiosàaligningaerialtotransmitsandreceive
- Superposition=onethingontopoftheother
àtwoormorewavescross,theresultant
displacementequalsthevectorsumofthe
individualdisplacement
Interferencecanbeconstructiveordestructive(diagram)
- Ifcrestandtrougharen'tsamesize,thendestructiveinterferenceisn'ttotal.…read more

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Togetinterferencepatternsthetwosourcesmustbecoherent
- Canstillhappenifthere'sadifferentwavelengthandfrequency,itsjustthatitsalla
jumbleàtwosourcesarecoherentiftheyhavethesameWAVELENGTH,FREQUENCY
andaFIXEDPHASEDIFFERENCE
- Cangetdestructive
interferencewhenthereis
ap.dofhalfawavelength,
oneandahalfwavelength
twoandahalfetc.=outof
phase
- Amountbywhichthepathtravelledbyonewaveislongerthanthepathtravelled
()*# + #
- ConstructivewhenP.D=n D.I= = +
( (
StationaryWaves:Progressivewavesreflectedataboundaryàstationary(standing)wave
isthesuperpositionoftwoprogressivewaveswiththesamefrequency(wavelength),
movinginoppositedirection
- Noenergyistransmittedbyastationarywaveàdemonstratedbysettingupadriving
oscillatoratoneandofastretchedstringwiththeotherendfixedàwavegenerated
buttheoscillatorisreflectedbackandforth
- Mostfrequencytheresultantpatternisajumbleàbutifoscillatorsproduceanexact
numberofwavesinthetimeittakesforthewavetogettotheendandback
- Atthese`resonantfrequencies'yougetastationarywavewherethepatterndoesnot
move.Itjustbobsupanddown
Stationarywavesformoscillatingloopsseparatedbynodes
- Eachparticlevibratesatrightanglestothestring.Nodeswhereamplitudeiszero
- Firstharmonic:
o
o Vibratingatlowestpossibleresonant
frequency.…read more

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Twicethefrequencyofthefirst
harmonic.Therearetwo"loops"withanodein
themiddleandoneateachend
-
(.
- =
)
- Whichmodeitsin
- Microwavesreflectedoffametalsurface/platesetupastationarywaveàFirstnodes
andanti-nodes
- PowdercanshowstationarywavesinatubeofairàLycopodiumpowderlaidalong
thebottomandthepowderisshakenawayfromtheantinodesbutleftundisturbedat
thenodes
Corepractical:investigatefactorsaffectingtheresonantfrequenciesofastring
1. Measuremass(M)andlength(L)ofdifferentstringtypesusingamassbalanceand
0
ruler.Thenfindthemassperunitlengthà =
.
2. Setupapparatusasshownindiagram.Recordµ,measureandrecordLandworkout
thetension(T)àT=mg màtotalmassofthemassesinkg
3. Turnonthesignalgeneratorandverythefrequencytillyoufindthefirstharmonic
- Theninvestigatehowthelength,tensionormassperunitlengthofthestringaffects
theresonantfrequency
- Showedthat:
1. Longestthestring=lowertheresonantfrequencyàhalfthewavelengthatthe
resonantfrequencyislonger
2. Theheavierthestring=lowerresonantfrequencyàwavestravelslower
makingfrequencylower
3.…read more

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Diffraction
- Amountofdiffractiondependsonthewavelengthcomparedtothesizeofthegap
o Gapgreaterthanthewavelength=diffractionunnoticeable
o Noticeablediffractionwhengapseveralwavelengthwide
o Mostdiffraction=samesizewavelength
o Gapsmaller=wavesreflectedback
- Lightshonethroughanarrowslitcanformdiffractionpatterns
o Needmonochromatic[samewavelengthandfrequency],coherentlightsource
samecolour
o
o Centralbrightfringe(centralmaximum),withdarkandbrightfringesalternating
oneitherside.Thedarkandbrightfringesarecausedbydestructiveand
constructiveinterferenceoflightwaves
- Diffractionofwhitelightcreatesaspectrum
o Centralmaxima=white
o Theblackfringesareclosertogetherandconstructivefringescreatedifferent
colours(spectra)
Intensityoflightmeansnumberofphotons
- Centralmaximaarethebrightestduetohavingthehighestintensity
6789:
- Intensity=
;:7<<<9=>?7)@1@:9@
- Formonochromaticlight,photonshavethesameenergy,soanincreaseintheintensity
meansanincreaseinthenumberofphotonspersecond
- Morephotonsperunitareahittingthecentralmaximumpersecondthantheother
brightfringes
àIncreasingslitwidthdecreasestheamountofdiffractionmeaningcentralmaximumis
narrowandtheintensityishigher
àIncreasingthewavelengthincreasestheamountofdiffractionmeaningthecentral
maximumiswider,andtheintensityofthecentralmaximumislower
Twosourceinterferenceinwaterandsounds
- Needcoherentsourcesàsamewavelengthandfrequency
- Needtousethesameoscillator
TwosourceinterferenceinlightàThomasYoung'sDoubleSlit
1.…read more

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Dangerofworkingwithlasers/prevent:
o Damageretina,warningsignsoutside,wearsafetygoggles,turnofflaserwhen
notneeded
Young'sDoubleSlitformula
+B
Fringespacing- = D=distancefromslittoscreen
<
S=Slitspacing
Fringespacing­Distancefromthecentreofoneminimumtothecentreofthenext
minimumorfromonecentralmaximumtotheother
Young'sexperiment:EvidenceofwavenatureofEMradiation
- Lightcouldrefract/diffractandinterfere
- Lightmadeupoftinycorpuscles
Diffractiongradient
- CanrepeatYoung'sdoubleslitexperimentwithmorethantwoequallyspacedslits
àsamepatternbutthebrightbandsarebrighterandnarrowerandthedarkbecomes
darker
- Monochromaticlightispassedthroughagratingwithhundredsofslitspermmsothe
interferencepattersissharpàmoreaccuratemeasurement
Monochromaticlightonadiffractiongratinggivessharplines
1. Monochromaticlightàallthemaxima'saresharplines
2. There'salineofmaximumbrightnessatthecentrecalledthezeroorderline
3. Linesjusteithersideofthecentralonearecalled1storders
4. Foragratingwithslitdistancedapart,theangle
betweentheincidentbeamandthenthorder
maximum =
Derivingtheequation:
1. Ateachslit,incomingwavesarediffracted.Thesediffractedwavesinterferewith
eachothertoproduceaninterferencepattern
2. Considerthefirstmaximum,happensattheanglewhen
thewavefromoneslitline-upwiththewavesfromthe
nextslitthatareexactlyonewavelengthbehind
3. Anglebetweenfirstordermacandincominglight
4. Angle(usinggeometry),distheslitspacingandthe
pathdifferenceis
5.…read more

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Sincan'thavegreaterthan1thereforeyou'llgettoacertainthereisnomoreorders
thatexist
DiffractionGratingshelptoidentifyelementsandcalculateatomicspacing
1. Whitelightisamixtureofcolours,ifyoudiffractwhitelightyougetaspectradueto
allthedifferentwavelengthsàspreadoutbydifferentamounts
2. Eachorder=spectrum,redontheoutsideandvioletontheinside.Thezeroorder
maximumstayswhitebecauseallpassthrough
3.…read more

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OpticalFibresuseTotalInternalReflection
1. Step ­ index optical fibres themselves have a high ­ refractive index but are
surroundedbycladdingwithalowerrefractiveindextoallowtotalinternalreflection
+protectsfibrefromscratches(lightcouldescape)
2. Light shone in at one end of the fibres, its narrow so light always hits a boundary
betweenthefibreandcladdingatananglebiggerthanthecriticalangle àalllight
T.I.Rfromboundarytoboundary
Dispersion&Absorption:Causesignaldegradation
- Absorptioncauseslossinamplitude,someenergyisfromwhatthematerialismadeup
ofàcausinglossof(A)ofsignalbeingreduced
z
Dispersioncausespulsebroadening
- Twotypes:
1. Modaldispersion­lightraysenterfibreatdifferentanglescausingdifferentpaths.
Rayswilltakelongertotravel.Singlemodefibreonlylighttakeonepathà
stoppingmodaldispersion
2.…read more

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Mechanics
- Scalaràmagnitudebutnodirection(mass,temperature,time,speed,energy)
- VectoràBothmagnitudeanddirection
- Representingvectors:
1. Lengthofthearrowrepresentsmagnitude
2. Directionofthearrowrepresentsthedirectionofthevector
Vectoraddition F1
- Vectorsalongthesamestraightline F2
- Resultant=F1+F2 Resultant
Combiningperpendicularvectors
- Tofindtheresultantoftwovectors(X,Y)actingat90°toeachotherwedrawvectorsas
adjacentsidestoeachother.Thisisduetothehorizontalandverticalcomponents
beingindependent
Y
- MagnitudeofRcanbeworkedoutbyR2=Y2+X2
T
- Directionoftheangleisworkedoutbytan =
U
X
Vectorsubtraction
- Whatistheboxesinspeed?
10m/s
o Changeinspeed=new­old
6m/s
à10­6=4ms-1
- What'sitschangeinvelocity?
o inV=newvelocity­old
o 10m/s(up)­6m/sdown
o thereforeà10­(-6)=16m/sasdownisnegative
· Vectorsubtractionisthesameastheadditionofavectorofthesamesizeactingin
theoppositedirection
Combiningonperpendicularvectorsbycalculations
6N X=60°
3N
x
2N
1. Resolvethe3Nlikeitshorizontalandvertical
Horizontalà3xcos30=2.6N
Verticalà3xcos60=1.5N
2. Replace3Ncomponent
2.6N
6N 1.…read more

Comments

LouiseG

ARBI my ******** computer crashed and saved the rating as 4* when I meant to press 5 b/c i was doing it on my phone and my fat fingers got in the way :(

I'm so sorry I I wanted to change it but I can't !!

Brilliant resource :D 5*

LouiseG

Good to see you got it back up to 5* :D

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