2021 4E Pure Phy 6091 Preliminary Examination - Paper 3 (QP)

Name:…………………………………………….. Indexno:……… Class:…………… NGEEANNSECONDARYSCHOOL O PRELIMINARYEXAMINATION PUREPHYSICS 6091/03 PAPER3 17August2021 1h50min READTHESEINSTRUCTIONSFIRSTWriteyourname,classandindexnumberonalltheworkyouhandin.Writeindarkblueorblackpen.YoumayuseaHBpencilforanydiagramsorgraphs.Donotusestaples,paperclips,glueorcorrectionfluid. SectionAandBAnswer allquestions.Youwillbeallowedtoworkwiththeapparatusforamaximumof55minutesforeachsection.Youareexpectedtorecordallyourobservationsassoonastheyaremade. Candidates are reminded that all quantitative answers shouldincludeappropriateunits.Theuseofanapprovedscientificcalculatorisexpected,whereappropriate.Candidatesareadvisedtoshowalltheirworkinginaclearandorderlymanner, asmoremarksareawardedfor sounduseofPhysicsthanforcorrectanswers. Attheendoftheexamination,fastenallyourworksecurelytogether.Thenumberofmarksisgiveninbrackets[ ]attheendofeachquestionorpartquestion. Checkedbystudent:_____________________Date:__________________ Thisdocumentconsistsof12printedpages(includingthiscoverpage).

2 SectionA(20marks) 1 Inthisexperiment youwill measurethetimetakentoraisethetemperatureof water byaBunsenBurner. Youareprovidedwith:● A250mlbeaker,● athermometer,● a250mlmeasuringcylinder,● astand,bossandclamp,● astopwatch,● aBunsenBurner,● atripodwithwiregauze.(a) Fig1.1hasbeensetupforyou. Usingthemeasuringcylinder,take150mlofwaterandpouritintothebeaker.Thedensityofwateris1.0g/cm 3 .Notethat1.0ml=1.0cm 3 ,recordthemassmofthewaterinkilogram. m=………………………………(b) Notethetemperatureθ1 ofthewater. θ1 =………………………………[1] (c) UsingtheBunsenBurner,lightupthenon-luminousflame(withair-holefullyopenedandmaximumgassupply).Placeitunderneaththetripodstand,heatthebeakerofwaterandstartyourstopwatch.Heatthewaterfor1minute. Waitforafewminutesandrecordthehighest steadytemperatureθ2 reachedbythewater. θ2 =………………………………[1](d) TheheatenergyQ0 givenoutbytheBunsenBurnerisP.twherePisthepoweroftheBunsenBurner,tisthedurationofheatinginseconds.TheheatgainedbythewaterisQ1 =mcΔθ,wheremisthemassofthewaterinthebeakerinkg, c=4200JK -1 kg -1 andΔθ=θ2 -θ1 .QL istheheatlosttothesurrounding.NAS/2021/Prelim/4E/Physics/03/6091

3 Q0 =Q1 +QL P.t=m.c. Δθ+QL CalculatethevalueofQL intermsofPwiththecorrectunit. QL =……………………………..[2] (e) Plan Theequationin(d)canbere-arrangedtotheform Δθ=[P/(m.c)].t–[QL /(m.c)] UsingthesameapparatusprovidedinFig1.1,plananexperimenttoinvestigatetheaboverelationship.Theapparatusprovidedarenotexhaustive,youmayincludemoreapparatusinyourplan. Yourplanshouldinclude● alistofthequantitiesthatremainconstant,● adescriptionofhowyouwouldperformtheexperiment,● asuitabletableinwhichtodisplayyourmeasurementsandcalculatedvalues(youdonotneedtoenteranydataintothetable),● astatementofthegraphyouwouldplottotesttherelationship,● anexplanationofhowPandQL arefoundfromthegraph,● stateonekeysourceoferrorintheexperimentandhowdoyouovercomeit.…………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… NAS/2021/Prelim/4E/Physics/03/6091

4 …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… ………………………………………………………………………………………...[6] 2 Inthisexperiment, youwill determineavaluefor thedensityof apieceof modellingclay. Youhavebeenprovidedwith ● a30cmruler,● aspring,● astand,bossandclamptosupportthespring,● apieceofmodellingclayattachedtoalengthofstringwithaloopatthetopofthestring, NAS/2021/Prelim/4E/Physics/03/6091

5 ● anS-hook(paperclipbentintoanS),● asupplyofwater,● a250cm 3 glassbeaker,● papertowelsorclothstomopupspillages,● anelectronicbalance. (a) Usingtheelectronicbalance,recordthemassofthemodellingclay. mass= [1] (b) Withthegivenapparatus,describehowyouwouldmeasurethevolumeofthemodellingclay. ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………[1] NAS/2021/Prelim/4E/Physics/03/6091

6 (c) Basedontheprocessdescribedin(b),determineandrecordthevolumeofthemodellingclay. volume= [1] (d) SetuptheapparatusasshowninFig.2.1. Fig. 2.1 SuspendtheS-hookfromthelowerendofthespring. (e) MeasurethelengthL0 ofthecoiledpartofthespring. L0 = [1] (f) Suspendthemodellingclayfromthehookusingtheloop.Themodellingclayshouldnottouchthebench.Measurethenewheight L1 ofthecoiledpartofthespring. L1 = (g) Calculatetheextensione1 ofthespringusinge1 =L1 –L0 . e1 = [1] (h) Placetheemptybeakerbelowthesuspendedmodellingclay. Lowertheclampuntilthemodellingclayisatthebaseofthebeakerandthestringbecomescompletelyslack. Pourwaterintothebeakeruntilthemodellingclayisfullyimmersedandcoveredbyabout1cmofwater.Iftheclaystartstofloat,thenlowertheclampfurther. Raisetheclampslowlyuntilthemodellingclayrisesfromthebottomofthebeakerbutisstillfullyimmersed.NAS/2021/Prelim/4E/Physics/03/6091

7 Ensurethatthemodellingclaydoesnottouchthesidesofthebeaker. (i) MeasurethenewlengthL2 ofthecoiledpartofthespring. L2 = (j) Calculatethenewextensione2 usinge2 =L2 –L0 e2 = [1] (k) Thedensityofwater, ρW ,is1.0g/cm 3 .Calculatethedensityρofthemodellingclayusing ρ= [2] (l) Usingtherecordedvaluesin(a)and(c),determinethedensityofthemodellingclay. density= [1] (m) Suggestwhythetwovaluesofdensityin(k)and(l)couldbedifferent. ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………[1] SectionB(20marks) 3 Inthisexperiment, youaregoingtodeterminetherefractiveindexof water inabeaker.Youhavebeenprovidedwith ● a600mlbeaker,● apieceofrectangularsoftboard, NAS/2021/Prelim/4E/Physics/03/6091

8 ● 4piecesofopticalpins,● apieceofwhiteA4paper,● aprotractor,● a30-cmplasticruler,● water. Fig. 3.1topviewof beaker of water (a) TracetheoutlineofthebaseofthebeakeronthewhiteA4paper.Removethebeaker.SeeFig3.1.(b) MarkapointA,onthecircumferenceofthecircle.(c) DrawthetangentXYofthecircleatpointA.(d) DrawalineperpendiculartothetangentXY,andlabelitNM.NMisthenormaltotangentXYatpointA.(e) Usingaprotractorandaruler,drawlineABsuchthattheangleXABis70 o .(f) Calculateangleofincidence,i,wherei=90 o -angleXAB.(g) Repeatstep(e)foranglesofXAB=80 o ,90 o ,100 o and110 o .Labeltheendofthelinesdrawnwiththeanglesofincidence,i.(h) Pourabout300mlofwaterintothebeaker.Placethebeakerofwaterontotheoutlineyouhavedrawninstep(a). NAS/2021/Prelim/4E/Physics/03/6091

9 (i) Insert2opticalpinsatP1 andP2 onlineAB.ThedistancebetweenP1 andP2 shouldbeabout3cm.SeeFig.3.1.(j) Usingonlyoneeye,viewtheimagesofpinsP1 andP2 fromtheoppositesideofthebeakerofwater.PositionyoureyesuchthattheimageofP2 coverstheimageofP1 .Withyoureyeinthesameposition,insertpinsP3 andP4 suchthattheyareinlinewiththeimagesofP1 andP2 .MarkthepositionsofP3 andP4 .RemovepinsP1 andP2 (k) Repeatstep(i)andstep(j)forvaluesofi=10 o ,0,-10 o and-20 o .(l) Removethebeakerofwater,drawthelineADtorepresenttherefractedray,measureangleMAD,theangleofrefraction,r.Notethatwhenangleofincidence,i,isnegative,angleofrefraction,r,willbenegativetoo.(m) Recordyourvaluesofi,r,siniandsinrinatable. [4] (n) Usingthegraphpaperinthenextpage,plotagraphofsinragainstsini. [4] (o) Fromyourgraph,commentonther