4E Phy Prelim 2021 P2

BOONLAYSECONDARYSCHOOL PRELIMINARYEXAMINATION 2021 Name ( ) Class Subject : PHYSICSPaperNo : 2SubjectCode : 6091/02Level : SECONDARYFOUREXPRESSDate/Day : 16SEPTEMBER/THURSDAYTime : 0815–1000Duration : 1HOUR45MINUTES READTHESEINSTRUCTIONSFIRST Donot openuntil youaretoldtodoso. Beforeyoustart your exam, checkthat youhavereceivedthecorrect paperandthenumberofprintedpagesarecorrect.Writeyournameandindexnumberonalltheworkyouhandin.Donotusestaples,paperclips,glueorcorrectionfluid. Theuseofanapprovedscientificcalculatorisexpected,whereappropriate.Youmaylosemarksifyoudonotshowyourworkingsorifyoudonotuseappropriateunits. INFORMATIONTOCANDIDATES SectionAAnswer allquestions.Writeyouranswersinthespacesprovided. SectionBAnswer allquestions.Writeyouranswersinthespacesprovided.Question12hasachoiceofpartstoanswer. Attheendofexamination,fastenallyourworksecurelytogether.Thenumberofmarksisgiveninbrackets[ ]attheendofeachquestionorpartquestion.

2 Thisquestionpaperconsistsof19printedpages. SectionA[50marks]Answer allthequestions. ForExaminer’sUse 1 Fig.1.1showsabungeeridewhichlaunchespeopleupwardsusingelasticcords.Eachcordappliesaforceof1000Nandthecordsareat60 o fromeachother. Drawasuitablescalediagramtodeterminethemagnitudeanddirectionof theresultantofthesetwoforces. BLS/Prelim/2021/4E/Physics/6091/02

3 scale=……………………………..resultantforce=…………………………….directionofresultantforce=……………………………. [5]2 AuniformrodABof length3.0mweighs10N.Itissuspendedbytwoidenticalstringsat pointsXandYasshowninFig. 2.1. T1 and T2 arethetensioninthestrings. ForExaminer’sUse Fig. 2.1 Twoweights,20Nand40N,arehungfromtherodatpointAand1.6mfromXrespectively. (a) DrawtheweightoftherodinFig.2.1andlabelitW.IndicateclearlyitsdistancefrompointA. [1] (b) DetermineT2 ,thetensionofthestringatY. T2 =……………………………. [2] (c) Hence,orotherwise,determineT1 ,thetensionofthestringatX. T1 =……………………………. [2] BLS/Prelim/2021/4E/Physics/6091/02

4 3 Astudentmeasuresthepressureinsideabicycletyreusingapressuregaugehehasconstructed.Fig.3.1showstheapparatusheuses.Thepistonandrodmovealongthesmoothcylindricaltube. Thechangeinlengthofthespringisproportionaltotheforceappliedtothespring.Aforceof2.8Ncompressesthespringby2.0cm. Thestudentconnectsthepressuregaugetothetyre.Airfromthetyreexertsaforceonthepiston.Asthepistonmoves,thespringiscompressed.Thepistonmoves10cmtotherightandthenstops. ForExaminer’sUse (a) Calculatetheforceexertedonthepistonbythespring. forceexerted=……………………………. [1] (b) Thecross-sectionalareaofthepistonis3.0×10 –5 m 2 .Calculatethepressureoftheairinsidethetyre. pressure=……………………………. [2] (c) Suggestonechangetotheapparatussothatthepistonisabletomeasureawiderrangeofpressurewithoutchangingthelengthoftheapparatus. ………………………………………………………………………………………….. [1] (d) Eachtimethat thepressuregaugeisused, thepressureinthetyrefallsslightly.Thevolumeofthetyreandtemperaturestayconstant.Describe,usingideasaboutmolecules,whythepressurefalls. …………………………………………………………………………………………..…………………………………………………………………………………………..…………………………………………………………………………………………..…………………………………………………………………………………………..………………………………………………………………………………………….. [2] BLS/Prelim/2021/4E/Physics/6091/02

5 4 (a) Fig.4.1showsthearrangementofatomsinasolidblock.EndXoftheblockisheated.EnergyisconductedtoendY,whichsoonbecomeswarm. Fig. 4.1 Theblockisheatedandbecomesaliquid.Describethechangesthatoccurtothearrangementandthemotionoftheatoms.…………………………………………………………………………………………..…………………………………………………………………………………………..…………………………………………………………………………………………..…………………………………………………………………………………………..………………………………………………………………………………………….. [1] (b) Explainthemaindifferencebetweenconductionandconvectionbymakingreferencetothedifferentmechanisminvolvedfortheheattransferprocesses.…………………………………………………………………………………………..…………………………………………………………………………………………..…………………………………………………………………………………………..…………………………………………………………………………………………..…………………………………………………………………………………………..…………………………………………………………………………………………..…………………………………………………………………………………………..………………………………………………………………………………………….. [2] BLS/Prelim/2021/4E/Physics/6091/02

6 5 (a) Fig.5.1showstheheatingcurveofasubstanceX. Theamount of Xusedintheexperimentwas400g.Theheaterusedwasratedat200W.Calculate ForExaminer’sUse (i) theamountofenergyrequiredformeltingsubstanceX, amountofenergy=……………………………. [2] (ii) thespecificlatentheatofvaporisationforsubstanceX. specificlatentheatofvaporisation=……………………………. [2] BLS/Prelim/2021/4E/Physics/6091/02

7 (b) Fig.5.2belowshowsaliquid-in-glassthermometerthatisnotcalibrated. Fig. 5.2 Describestepstoobtainthelowerfixedpointforthethermometer.Youmayincludeadiagraminyouranswer. ForExaminer’sUse …………………………………………………………………………………………..…………………………………………………………………………………………..…………………………………………………………………………………………..………………………………………………………………………………………….. [2] BLS/Prelim/2021/4E/Physics/6091/02

8 6 (a) Aparallel beamof light makinganangleof 30°withtheprincipal axisisincidentonthelensasshownintheFig.6.1. ForExaminer’sUse (i) CompletetheraydiagraminFig.6.1tolocatetheimageofthetree. [2] (ii) Definethetermfocallengthofthelens.………………………………………………………………………………….. [1] (b) Fig.6.2showsthreelightraysemittedfromaraybox.Thelightraysfromtheslit of the box shines on the liquid surface XY at different angles. [2] (i) Iftherefractiveindexofliquidis1.43,calculatethecriticalanglefortheliquid. criticalangle=……………………………. [2] BLS/Prelim/2021/4E/Physics/6091/02

9 (ii) Complete the ray diagramusing the above diagramto showthesubsequentpathofthethreelightraysaftermeetingtheliquidsurfaceXY.ShowyourworkingandindicatealltheanglesclearlyinFig.6.2. [3]7 WhenmovingfrompositionGtoL,ashipsendspulsesofultrasonicwavesatafrequencyof45000GHzcontinuouslytowardsthebottomofthesea.Thevariationof thetimeinterval, t, betweentheemissionof apulseandthereceptionof itsreflectionisshowninFig.7.1.Takethespeedofsoundinwateras1350m/s. ForExaminer’sUse (a) Calculate (i) thedepthdifferencebetweenpositionJandL depthdifference=……………………………. [2] (ii) thewavelengthoftheultrasoundwavesinwater. wavelength=……………………………. [2] (b) StateonereasonwhythedepthoftheseabedchangesabruptlywithinafewmetresfromItoJ. …………………………………………………………………………………………..………………………………………………………………………………………….. [1] (c) Stateoneotherapplicationofultrasound. ………………………………………………………………………………………….. [1] BLS/Prelim/2021/4E/Physics/6091/02

10 8 Fig. 8.1belowshowsanunchargedmetal spherehungonaninsulatedthreadbetweentwometalplatesXandY,whichareconnectedtoacircuit. ThesphereisbroughttotouchplateXmomentarilyandthenreleased. ForExaminer’sUse (a) Statewhetherthemetal sphereispositivelychargedornegativelychargedafteritwasfirstbroughttotouchX. ………………………………………………………………………………………….. [1] (b) Describe and explain the subsequent motion of the sphere after beingreleased. …………………………………………………………………………………………..…………………………………………………………………………………………..…………………………………………………………………………………………..…………………………………………………………………………………………..………………………………………………………………………………………….. [3] (c) Explainwhytheammetershowsaperiodiccurrentwiththesubsequentmotionofthesphere. …………………………………………………………………………………………..…………………………………………………………………………………………..………………………………………………………………………………………….. [1] BLS/Prelim/2021/4E/Physics/6091/02