igcse物理考136卷15年前真题

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Paper3(ExtendedTheory),

umrawmark80

CAMBRIDGEINTERNATIONALEXAMINATIONS

InternationalGeneral ofSecondaryEducation

MARKSCHEMEfortheOctober/November2013series

Thismarkschemeispublishedasanaidtoteachersandcandidates,toindicatetherequirementsoftheexamination.ItshowsthebasisonwhichExaminerswereinstructedtoawardmarks.ItdoesnotindicatethedetailsofthediscussionsthattookceatanExaminers’meetingbeforemarkingbegan,whichwouldhaveconsideredtheacceptabilityofalternativeanswers.

MarkschemesshouldbereadinconjunctionwiththequestionpaperandthePrincipalExaminerReportforTeachers.

Cambridgewillnotenterintodiscussionsaboutthesemarkschemes.

CambridgeispublishingthemarkschemesfortheOctober/November2013seriesformostIGCSE,GCEAdvancedLevelandAdvancedSubsidiaryLevelcomponentsandsomeOrdinaryLevelcomponents.

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NOTESABOUTMARKSCHEMESYMBOLS&OTHERMATTERS

Mmarksaremethodmarksuponwhichfurthermarksdepend.ForanMmarktobescored,thepointtowhichitrefersmustbeseeninacandidate'sanswer.IfacandidatefailstoscoreaparticularMmark,thennoneofthedependentmarkscanbescored.

Bmarksareindependentmarks,whichdonotdependonothermarks.ForaBmarktoscored,thepointtowhichitrefersmustbeseenspecificallyinthecandidate’sanswers.

AmarksIngeneralAmarksareawardedforfinalanswerstonumericalquestions.Ifafinalnumericalanswer,eligibleforAmarks,iscorrect,withthecorrectunitandanacceptablenumberofsignificantfigures,allthemarksforthatquestionarenormallyawarded.Itisveryoccasionallypossibletoarriveorrectanswerbyanentirelywrongapproach.Intheserarecircumstances,donotawardtheAmarks,butawardCmarksontheirmerits.However,correctnumericalanswerswithnoworkingshowngainallthemarksavailable.

Cmarksarecompensatorymarksingeneralapplicabletonumericalquestions.Thesecanbescoredevenifthepointtowhichtheyreferarenotwrittendownbythecandidate,providedsubsequentworkinggivesevidencethattheymusthaveknownit.Forexample,ifanequationcarriesaCmarkandthecandidatedoesnotwritedowntheactualequationbutdoescorrectsubstitutionorworkingwhichshowsheknewtheequation,thentheCmarkisscored.ACmarkisnotawardedifacandidatemakestwopointswhichcontradicteachother.Pointswhicharewrongbutirrelevantareignored.

Brackets()aroundwordsorunitsinthemarkschemeareintendedtoindicatewordingusedtoclarifythemarkscheme,butthemarksdonotdependonseeingthewordsorunitsinbrackets,e.g.10(J)meansthatthemarkisscoredfor10,regardlessoftheunitgiven.

Underliningindicatesthatthismustbeseenintheansweroffered,orsomethingverysimilar.

OR/or indicatesalternativeanswers,anyoneofwhichissatisfactoryforscoringthemarks.

e.e.o.o. means"eacherrororomission".

o.w.t.t.e. means“orwordstothateffect”.

c.a.o. means“correctansweronly”.

SpellingBegenerousaboutspellinganduseofEnglish.However,donotallowambiguities,e.g.spellingwhichsuggestsconfusionbetweenreflection/refraction/diffractionorthermistor/transistor/transformer.

Not/NOTindicatesthatanincorrectanswerisnottobedisregarded,butcancelsanotherotherwisecorrectalternativeofferedbythecandidatei.e.rightpluswrongpenaltyapplies.

Ignore indicatesthatsomethingwhichisnotcorrectorirrelevantistobedisregardedanddoesnotcausearightpluswrongpenalty.

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e.c.f. meaning"errorcarriedforward"ismainlyapplicabletonumericalquestions,butmayinparticularcircumstancesbeappliedinnon-numericalquestions.Thisindicatesthatifacandidatehasmadeanearliermistakeandhascarriedanincorrectvalueforwardtosubsequentstagesofworking,marksindicatedbye.c.fmaybeawarded,providedthesubsequentworkingiscorrect,bearinginmindtheearliermistake.Thispreventsacandidatebeingpenalisedmorethanonceforaparticularmistake,butonlyappliestomarksannotatede.c.f.

SignificantFigures

Answersarenormallyacceptabletoanynumberofsignificantfigures≥2.Anyexceptionstothisgeneralrulewillbespecifiedinthemarkscheme.

Units Deductonemarkforeachincorrectormissingunitfromafinalanswerthatwouldotherwisegainallthemarksavailableforthatanswer:um1perquestion.

Arithmeticerrors

Deductonemarkiftheonlyerrorinarrivingatafinalanswerisclearlyanarithmeticone.

Transcriptionerrors

Deductonemarkiftheonlyerrorinarrivingatafinalanswerisbecausegivenorpreviouslycalculateddatahasclearlybeenmisreadbutusedcorrectly.

Fractions Onlyacceptthesewherespecifiedinthemarkscheme.

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1 (a)measurearea(undercurve)

B1

[1]

(b)drawstangentatsteepestpartbyeye,withinthicknessoflines

accepttriangle/linestoindicatevaluesonstraightsteepestpartofcurve

B1

finds∆vand∆tfromtangentoratstraightsteepestpartofcurve

B1

anyvdividedbyanytorinequation

B1

2

3.0–4.2m/s

B1

[4]

(c)uses62and10 NOT2×62

6.2m/s

C1A1

[2]

[Total:7]

2

(a)

evidenceofdivisionof12mmby0.080s

C1

(v=)0.15m/sor150mm/s

C1

usest=his(∆)v/ainanyform

C1

(t=[0.15–0]/0.03=0.15/0.03)=5(.0)saccept1sig.fig.

allowe.c.f.fromclearlyidentifiablewrongspeed

A1

[4]

(b)useofF/aORF=mainanyform,numbersorsymbols,ignoreg

C1

(0.06/0.03=)2(.0)kgaccept1significantfigure

A1

[2]

(c)greater

M1

becausemassisless,ignorecommentsabout

A1

[2]

[Total:8]

3 (a)(i)(bothhave)magnitudeo.w.t.t.e. B1(only)vectorhasdirection B1 [2]

(ii)validexampleofvector ty

e.g.discement,weight, ,velocity B1

validexampleofscalarty

e.g.distance,length,time,pressure,mass,energyacceptheight B1 [2]

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(b)eachvectortoscaleandcorrectangle,

largervectorclockwisebyacuteanglefromsmaller B1

parallelogramorcorrecttwosidesoftriangle B1resultantdrawncorrect,fromhisparallelogramorhiesoftriangle M1

4

4

magnitude4.5–5.4×104N,accept1sig.fig.ifexact

ANDdirection4–12°from3×10NOR8–16°from2×10N

acceptvaluesfromdiagram A1 [4]

[Total:8]

4 (a)irregular/random/haphazardmovement

B1

anymentionofdifferentdirectionsorclearlydescribed

B1

[2]

(b)smokeparticlescondoneatoms,moleculesetc.AND(invisible)airmolecules

B1

airandsmoke/dotscollideignoreothercollisions

B1

[2]

(c)dotsmoveinoroutoffocus/disappearORappearbrighter/dimmer

B1

[1]

[Total:5]

5 (a)blackcan/Blosesheatenergyquicker/coolsfaster

ORpolishedcanlosesheatenergyslower/coolsslower M1

blackradiates/emitsmoreORpolishedradiates/emitsless

ignoreanythingaboutabsorption A1 [2]

(b)(i)anyfourfrom: B4

viableexperimente.g.pourinwandmeasuretemperatureignoremethodswithexternalthermometers(forthispointonly)

pour(hot)waterintobothcanstosamelevel/sameamount

cethermometersinsamepositionrelativetoeachcan/detailrelatingtostirring

thermometersnottouchingthemetalofcanobservechangeoftemperature

correctdetailoftiming

repeatreadings [4]

(ii)usetilesaslids

reduceconvection/evaporation(toroom)

M1

A1

ORalternativemethodputtilesundercans

(M1)

reduce,ignoreprevent,conduction(tobench)

(A1)

forbothmethods,ignoreothermodesofheattransfer,ignorearoundcan

cetiles

[2]

(c)blackcan/B

M1

blackabsorbs(radiation)better,ignoreanythingaboutemission

A1

[2]

[Total:10]

6

(a)

lightinairsoundinairsoundinwater

BOX5 3×108m/s

BOX2 300m/s

BOX3 1500m/s

B1B1

B1

[3]

(b)distance=speed×timeinanyformNOTspeed=2d/t

C1

tair=120÷valueforspeedofsoundinair

C1

trail(=120/5000)=0.024s

C1

(timedifference=)candidate’stair–candidate’strailcorrectlyevaluated(expect0.400–0.024=0.376s)

A1

[4]

[Total:7]

7

(a)

(i)

BOX2ticked

virtual

B1

(ii)

BOX3ticked

ABcircled

magnified

B1

B1

[3]

(i)normalatMtowardsC B1 [1]

40°≤angleofreflection≤50° B1 [1]

anyclearindicationthatOPisalsothereflectedray B1 [1]

line tendedbackfromMandPtomeettotherightofmirror

ANDindicationofintersectionasimageposition M1

imagewithin25mmofrighthandmarginline

ANDhigherthanPbutwithin16mm A1 [2]

[Total:8]

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8

(a)(onethirdlengthso)onethirdR,acceptanydivisionby3

C1

(halfareaso)twiceR,acceptanydoubling,includingdivideby½

C1

( =0.45×2/3)=0.3(0)Ωaccept1sig.fig.

A1

[3]

(b)(i)1(Ω)and3(Ω)usedincorrectparallelformula

C1

2(Ω)addedtocandidate’sparallel

C1

2.7or2.8or2.75Ω

A1

[3]

(ii)any2from:

I1=I4ORI1=I2+I3ORI4=I2+I3

ORothercorrectrelevantequation/inequalitye.g.I4=4I3,I4>I3

B2

[2]

(iii)any2from:

V1=V4ORV1=V2+V3ORV4=V2+V3

ORcorrectrelevqualitye.g.V1>V3

B2

[2]

[Total:10]

9 (a)(i) currenectricitycouldflowthrough