Prelim 2021 - Physics Pract P3

Class Indexno.Name: DEYI SECONDARY SCHOOL PreliminaryExamination2021SecondaryFour Express PHYSICS 6091/03Paper3Practical 12August2021 1hour50minutesCandidatesanswerontheQuestionPaper.AdditionalMaterials:AslistedinInstructionstoSupervisors._________________________________________________________________________ READTHESEINSTRUCTIONSFIRST Donot openthesebookletsuntil youaretoldtodoso.Writeyour nameandclass/register numberinthespacesabove.Writeindarkblueorblackink. YoumayuseanHBpencilforanydiagramsorgraphs.Donotusestaples,paperclips,glueorcorrectionfluid. Answer allquestions.AllofyouranswersshouldbewritteninthisQuestionPaper:scrappapershouldnotbeused.GraphpaperisprovidedinthisQuestionPaper. Additionalsheetsofgraphpapershouldbeusedonlyifitisnecessarytodoso. Youwillbeallowedtoworkwiththeapparatusforamaximumof55minutesforeachsection.For Examiner’sUse 1 2 3 Total Youareexpectedtorecordallyourobservationsassoonastheseobservationsaremade.Anaccountofthemethodofcarryingouttheexperimentsisnotrequired.Theuseofanapprovedscientificcalculatorisexpected,whereappropriate. At theendof theexamination, fastenall your worksecurelytogether.

2 Thenumberofmarksisgiveninbrackets[ ]attheendofeachquestionorpartquestion. SectionA 1 Inthisexperiment,youwillinvestigatetheextensionofaspring. Youhavebeenprovidedwith ● alengthofstringtiedtoaspring,● anS-hook,● astand,bossandclamp,● apieceofplasticpipe,● amassofweight1.5N,● asetsquare,● a30cmruler,● a50cmrule,● ametrerulefixedtothebenchwithBlu-tac,● aloopofstringonthemetrerule. (a)(i) Measureandrecordtheunstretchedlengthlo ofthespring,asshowninFig. 1.1. Fig. 1.1 lo =……………………..[1]

3 (a)(ii) Placeoneoftheloopsofthespringontotherodoftheclamp,asshowninFig. 1.2.Suspendthemassontheotherloop. Fig. 1.2 Measureandrecordthestretchedlengthls ofthespring.Determinetheextensioneo ofthespringusingtheequationeo =ls –lo . ls =……………………...[1] eo =……………………...[1] (b) Useyourvalueof eo from (a)(ii)andtheequationF=keo , whereF=1.5N,todetermine thespringconstantkforthespring. k=……………………...[1] [Turnover

4 (c) Removethespringfromtherodoftheclamp.Placetheplasticpipeintheclamp.Adjust theheightofthebosssothatthecentreoftheplasticpipeis50cmabovethebench.Adjustthepositonoftheclampstandsothatthecentreoftheplasticpipeisalignedwiththe50cmmarkonthemetrerule. AttachtheS-hooktotheloopofstringonthemetrerule.AttachthespringtotheS-hook.Placethestringovertheplasticpipeandsuspendthemassfromtheloopattheendofthestring,asshowninFig. 1.3. Fig. 1.3 (i) Adjustthepositionoftheloopofstringonthemetreruleuntilthespringisvertical. Measureandrecordthestretchedlengthl1 ofthespring.Determinetheextensione1 ofthespringusingtheequatione1 =l1 –lo . l1 =……………………...…… e1 =……………………...…[1]

5 (c)(ii) Withthemassstillsuspendedfromthestring,carefullymovetheloopofstringonthemetrerulesothatitisatthe15cmmark. Measureandrecordthestretchedlengthl2 ofthespring.Determinetheextensione2 ofthespringusingtheequatione2 =l2 –lo . l2 =……………………...……… e2 =……………………...……[1] (d) Useyourvalueofk,valuesofe1 ande2 andtheequationfrom(b)tocalculatetheforcesF1 andF2 inthespringwiththeloopinthetwodifferentpositionsonthemetrerule. F1 =……………………...……[1] F2 =……………………...……[1] (e) ExplainwhyF1 isnotequaltotheweightofthemassonthespring. [1] ………………………………………………………………………………………………...... ………………………………………………………………………………………………….. ………………………………………………………………………………………………….. (f) Identifyonesourceoferrorinthisexperiment. [1] ………………………………………………………………………………………………….. ………………………………………………………………………………………………….. ………………………………………………………………………………………………….. [Turnover

6 2 Inthisexperiment,youwillinvestigateatypeofsemi-conductingdiodecalledalight-emittingdiode(LED),whichisasemiconductordiodethatemitslight. Youhavebeenprovidedwith ● apowersupply,● aswitch,● alight-emittingdiode(LED),● a10Ωresistor,● avoltmeter,● anammeter,● avariableresistor● connectingleads. YouaretosetupthecircuitasshowninFig. 2.1. Fig. 2.1 (a) Closetheswitchandadjustthevariableresistortothemaximumresistance.ConnectavoltmeteracrosstheLED.RecordthecurrentI1 shownontheammeterandthepotentialdifferenceV1 shownonthevoltmeter. I1 =…………………[1] V1 =……………..….[1] (b) UsingtheformulaP=IV,calculatethepowerPdissipatedintheLEDusingthevaluesfoundin(a). power=………………..[1](c) RemovethevoltmeterandconnectitacrosspointsPandQ.

7 RecordthecurrentIshownontheammeterandthepotentialdifferenceVshownonthevoltmeter. I=…………………….…… V=……………………...[1](d) Plan AstudentsuggeststhatthecurrentIislinearlyrelatedtothepotentialdifferenceVacrosspointsPandQsuchthatV=kI+c. Plananexperimenttoinvestigatethisrelationship. Yourplanshouldinclude ● thequantitiesthatyouwillkeepconstant,● adescriptionofhowyouwouldperformtheinvestigation,● anindicationofhowyouwillachieveaccurateresults,● astatementofthegraphyouwouldplottotesttherelationship,● anexplanationofhowkwouldbefoundfromthegraph. …………………………………………………………………….…………………………….. …………………………………………………………………….…………………………….. …………………………………………………………………….…………………………….. …………………………………………………………………………………………………... …………………………………………………………………………………………………... …………………………………………………………………………………………………... …………………………………………………………………………………………………... …………………………………………………………………………………………………... …………………………………………………………………………………………………... …………………………………………………………………………………………………... …………………………………………………………………………………………………... [Turnover

8 …………………………………………………………………………………………………... …………………………………………………………………………………………………... …………………………………………………………………………………………………... …………………………………………………………………………………………………... …………………………………………………………………………………………………... …………………………………………………………………………………………………... …………………………………………………………………………………………………... …………………………………………………………………………………………………... …………………………………………………………………………………………………... …………………………………………………………………………………………………... …………………………………………………………………………………………………... …………………………………………………………………………………………………... …………………………………………………………………………………………………... …………………………………………………………………………………………………... …………………………………………………………………………………………………... …………………………………………………………………………………………………... ………………………………………………………………………………………………..[6]

9 SectionB 3 Inthisexperiment,youwillinvestigatehowrayscomingfromanobjectwhichhavebeenreflectedbyaplanemirrorchangewhenthepositionofthemirrorchanges. Youhavebeenprovidedwith● aplanemirrorwithalinedrawninthemiddle● amirrorstand● fouropticalpins● anA4plainpaper● asoftboard● ahalfmetrerule (a) Onapieceofplainpaper,drawthreelinesparalleltoalongedgeasshowninFig. 3.1.LabeltheselinesasshowninFig. 3.1. Placeapin,toactasanobject,atapoint OonthelineCDsuchthatthedistanceODis2.0 cm as shown in Fig. 3.2.[2] (b) Theplanemirrorwhichistobeusedhasalinedrawnonitsface.Setthismirrorontheline ABsothatthelineonthemirrorisverticalanddirectlyaboveapoint XonthelineAB,suchthat XBis4.0cmasshowninFig. 3.2. (c) Bylookingintothemirror,observetheimageofthepinplacedat O.Placetwopins,P1 andP2 ,suchthattheyareinlinewiththelineonthesurfaceofthemirroratpoint Xandtheimageoftheobject. [1] (d) Onthetrace,drawXP2 ,thedirectionofthereflectedray.Markthepoint Y,wherethelineXP2 ,crossesthelineEF. (e) Measureandrecordthedistancex=XBandthedistancey=YF. [Turnover

10 (f) ByplacingthemirroratdifferentpositionsonthelineAB,repeatsteps(b)to(e)forvaluesofx. Recordyourresultsforxandyinatable.Thevaluesforxandyshouldberecordedincentimetres.Alsoincludeyourresultsfrom(e)inthetable. [5] (g) Itissuggestedthattherelationshipbetweenxandyisgivenbytheequation y=Gx+C whereGandCareconstants. (h) Plotagraphofyagainstxusingthegraphpaperprovidedonpage12. [5] (i) DeterminetheconstantG,showingclearlyonyourgraphhowyoudidthis. [2] G=………….…………… (j) WiththevalueofGcalculatedin(i),determinethevalueofconstantC. [1]