2021 Physics-nht Written examination
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PHYSICS Written examination Wednesday 26 May 2021 Reading time: 10.00 am to 10.15 am (15 minutes) Writing time: 10.15 am to 12.45 pm (2 hours 30 minutes) QUESTION AND ANSWER BOOK Structure of book Section Number of questions Number of questions to be answered Number of marks A 20 20 20 B 18 18 110 Total 130 • Students are permitted to bring into the examination room: pens, pencils, highlighters, erasers, sharpeners, rulers, pre-written notes (one folded A3 sheet or two A4 sheets bound together by tape) and one scientific calculator. • Students are NOT permitted to bring into the examination room: blank sheets of paper and/or correction fluid/tape. Materials supplied • Question and answer book of 33 pages • Formula sheet • Answer sheet for multiple-choice questions Instructions • Write your student number in the space provided above on this page. • Check that your name and student number as printed on your answer sheet for multiple-choice questions are correct, and sign your name in the space provided to verify this. • Unless otherwise indicated, the diagrams in this book are not drawn to scale. • All written responses must be in English. At the end of the examination • Place the answer sheet for multiple-choice questions inside the front cover of this book. • You may keep the formula sheet. Students are NOT permitted to bring mobile phones and/or any other unauthorised electronic devices into the examination room. © VICTORIAN CURRICULUM AND ASSESSMENT AUTHORITY 2021 SUPERVISOR TO ATTACH PROCESSING LABEL HERE Victorian Certificate of Education 2021 STUDENT NUMBER Letter
Transcript of 2021 Physics-nht Written examination
PHYSICSWritten examination
Wednesday 26 May 2021 Reading time: 10.00 am to 10.15 am (15 minutes) Writing time: 10.15 am to 12.45 pm (2 hours 30 minutes)
QUESTION AND ANSWER BOOK
Structure of bookSection Number of
questionsNumber of questions
to be answeredNumber of
marks
A 20 20 20B 18 18 110
Total 130
• Studentsarepermittedtobringintotheexaminationroom:pens,pencils,highlighters,erasers,sharpeners,rulers,pre-writtennotes(onefoldedA3sheetortwoA4sheetsboundtogetherbytape)andonescientificcalculator.
• StudentsareNOTpermittedtobringintotheexaminationroom:blanksheetsofpaperand/orcorrectionfluid/tape.
Materials supplied• Questionandanswerbookof33pages• Formulasheet• Answersheetformultiple-choicequestions
Instructions• Writeyourstudentnumberinthespaceprovidedaboveonthispage.• Checkthatyournameandstudent numberasprintedonyouranswersheetformultiple-choice
questionsarecorrect,andsignyournameinthespaceprovidedtoverifythis.• Unlessotherwiseindicated,thediagramsinthisbookarenotdrawntoscale.• AllwrittenresponsesmustbeinEnglish.
At the end of the examination• Placetheanswersheetformultiple-choicequestionsinsidethefrontcoverofthisbook.• Youmaykeeptheformulasheet.
Students are NOT permitted to bring mobile phones and/or any other unauthorised electronic devices into the examination room.
©VICTORIANCURRICULUMANDASSESSMENTAUTHORITY2021
SUPERVISOR TO ATTACH PROCESSING LABEL HEREVictorian Certificate of Education 2021
STUDENT NUMBER
Letter
2021PHYSICSEXAM(NHT) 2
SECTION A – continued
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Question 1Awirecarryingacurrent,I,of6.0Apassesthroughamagneticfield,B,ofstrength1.4×10–5T,asshownbelow.Themagneticfieldisexactly1.0mwide.
1.0 m
B = 1.4 × 10–5 T
I = 6.0 A
ThemagnitudeoftheforceonthewireisclosesttoA. 0NB. 2.3×10–6NC. 8.4×10–5ND. 4.3×105N
SECTION A – Multiple-choice questions
Instructions for Section AAnswerallquestionsinpencilontheanswersheetprovidedformultiple-choicequestions.Choosetheresponsethatiscorrectorthatbest answersthequestion.Acorrectanswerscores1;anincorrectanswerscores0.Markswillnotbedeductedforincorrectanswers.Nomarkswillbegivenifmorethanoneansweriscompletedforanyquestion.Unlessotherwiseindicated,thediagramsinthisbookarenotdrawntoscale.Takethevalueofgtobe9.8ms–2.
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SECTION A – continuedTURN OVER
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Question 2Threecharges,–Q,+2Qand+2Q,areplacedattheverticesofanequilateraltriangle,asshownbelow.
–Q
+2Q+2Q
Whichoneofthefollowingarrowsbestrepresentsthedirectionofthenetforceonthecharge–Q?
A. B.
C. D.
Question 3A45ggolfball,initiallyatrest,ishitbyagolfclub.Thecontacttimebetweentheclubandtheballis 0.50ms.Themagnitudeofthefinalvelocityoftheballis41ms–1.Whichoneofthefollowingisclosesttotheaverageforceexperiencedbythegolfball?A. 0.18kNB. 0.37kNC. 1.8kND. 3.7kN
Question 4Apersonhasamassof60.0kg.WhichoneofthefollowingisclosesttotheweightofthispersononEarth’ssurface?A. 60.0kgB. 60.0NC. 588kgD. 588N
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SECTION A – continued
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Question 5WhenaspacecraftorbitsEarth,itsorbitalperiodisnotafunctionoftheA. massofEarth.B. massofthespacecraft.C. velocityofthespacecraft.D. heightofthespacecraftaboveEarth.
Question 6ThemainsvoltageinaparticularpartofAustraliaisACwithavoltageof240VRMS.Whichoneofthefollowingisclosesttothepeak-to-peakvoltage,Vp–p ,forthismainsvoltage?A. 170VB. 340VC. 480VD. 680V
Question 7Electricalpowerstationsareoftensituatedfarfromthecitiesthatrequirethepowerthattheygenerate.Whichoneofthefollowingbestdescribesthereasonforthehigh-voltagetransmissionofelectricalenergy?A. Transformerscanbeusedtoincreasethevoltageinthecities.B. Highvoltagesreducetheenergylossesinthetransmissionlines.C. Highvoltagesprovidethelargecurrentsneededforefficienttransmission.D. Highvoltagescanreducetheoveralltotalresistanceinthetransmissionlines.
Question 8Inthediagrambelow,thesolidlinerepresentsthegraphofoutputEMF,ε,versustimeproducedbyan ACgenerator.AsinglechangeismadetotheACgeneratoranditsoperation,andthenewgraphofoutputEMF,ε,versustimeisshownasadashedline.
0.05 0.10 0.15 0.20
ε (V)
10
5
0
–5
–10
t (s)
WhichoneofthefollowingbestdescribesthechangemadetotheACgenerator?A. Theareaofthecoilwasdoubled.B. Thespeedofrotationwashalved.C. Thespeedofrotationwasdoubled.D. Thenumberofturnsofthewireinthecoilwasdoubled.
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SECTION A–continuedTURN OVER
Question 9Thediagrambelowshowsabarmagnetmovingupwardintoacoil.
A
N
Whichofthefollowingcorrectlyidentifiesthedirectionoftheinducedcurrent,asviewedfromthetopofthecoil,andthedirectionofthemagneticfieldproducedbytheinducedcurrentinsidethecoil?
Current direction Magnetic field direction
A. clockwise ↓
B. clockwise ↑
C. anticlockwise ↑
D. anticlockwise ↓
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SECTION A–continued
Use the following information to answer Questions 10 and 11.Melissalaunchesaballfromheighthabovethegroundataspeedof8.0ms–1andatanangleof30°abovethehorizontal.Thetimeoftheball’sflightis1.0s.Thediagrambelowshowsthetrajectoryoftheball.
h
30°8.0 m s–1
trajectory
ball lands here
ball
ground level
Question 10Ignoringairresistance,whichoneofthefollowingisclosesttothehorizontaldistancethattheballlandedfromMelissa?A. 4.6mB. 5.0mC. 6.9mD. 8.0m
Question 11Whichoneofthefollowingdiagramsbestshowsthedirectionoftheresultantforce,F,ontheballatthepositionofmaximumheightintherealsituationwhereairresistanceisnotignored?
A.
C.
B.
D.
F
F
F
F
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SECTION A–continuedTURN OVER
Question 12Amassattheendofanidealspringisoscillatingfreelyupanddown.
top of motion
bottom of motion
Whichoneofthefollowingbestdescribesthemotionofthisoscillatingmass?A. Itsspeedisaminimumonlyatthetopofthemotion.B. Itsspeedisamaximumwhenitsaccelerationisamaximum.C. Itsaccelerationhasaminimumvalueatboththetopandthebottomofthemotion.D. Itsaccelerationhasamaximumvalueupwardwhenthemassisstationaryatthebottom.
Question 13JoannaisanobserverinSpaceshipPandiswatchingSpaceshipQflypastatarelativespeedof0.943c(γ=3.00).Sheobservesastationaryclockmeasuringatimeintervalof75.0sbetweentwoeventsinSpaceshipQ.Thisisapropertimeinterval.
Spaceship P
Spaceship Q
WhichoneofthefollowingisclosesttothetimeintervalobservedbetweenthetwoeventsinSpaceshipP’sframeofreference?A. 15.0sB. 25.0sC. 125sD. 225s
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SECTION A–continued
Question 14Thediagrambelowrepresentsastandingwave.
P
fixedwall
fixedwall
standing wave
ThepointPonthestandingwaveisA. anoderesultingfromdestructiveinterference.B. anoderesultingfromconstructiveinterference.C. anantinoderesultingfromdestructiveinterference.D. anantinoderesultingfromconstructiveinterference.
Question 15ThepolarisationoflightsupportsA. thewavemodeloflight.B. theparticlemodeloflight.C. boththewavemodelandtheparticlemodeloflight.D. neither thewavemodelnortheparticlemodeloflight.
Question 16Aredlaserusedinadouble-slitexperimentcreatesaninterferencepatternonascreen,asshownbelow.
slits
S1 S2
laser
laser beam
bright banddark band
screen
Theredlaserisreplacedwithagreenlaser.Whichoneofthefollowingbestexplainswhathappenstothespacingbetweenadjacentbrightbandswhenthegreenlaserisused?A. Thespacingincreases.B. Thespacingdecreases.C. Thespacingstaysthesame.D. Thespacingcannotbedeterminedfromtheinformationgiven.
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END OF SECTION ATURN OVER
Question 17Protonsofmass1.67×10–27kgareacceleratedtoaspeedof2.0×103ms–1.ThebestestimateofthedeBrogliewavelengthoftheseprotonsisA. 1.2×10–10mB. 2.0×10–10mC. 1.2×10–7mD. 2.0×10–7m
Question 18Experimentsonthephotoelectriceffectinvolveshininglightontoametalsurface.Measurementsaremadeofthenumberofemittedelectronsandtheirmaximumkineticenergyfromthemetalsurface.Thisisdonefordifferentfrequenciesandintensitiesoflight.Whichoneofthefollowingstatementswouldnotbeoneoftheexperimentalfindings?A. Theabilitytoejectelectronsfromthismetaldependedonlyonthefrequencyoflight.B. Thestoppingpotentialforthephotoelectronswasindependentofthelightintensity.C. Themaximumkineticenergyofthephotoelectronsdependedonlyonthelightintensity.D. Atfrequenciesbelowthethresholdfrequency,noelectronswereejectedfromthismetalnomatterhow
highthelightintensitywas.
Question 19Inanexperimentalinvestigation,anindependentvariableisonethatisA. independentoftheinvestigator’scontrol.B. avalueselectedbytheinvestigator.C. fixedthroughouttheexperiment.D. thekeyvariabletobemeasured.
Question 20Anucleusinanexcitedenergystateemitsagammarayofenergy3.6×10–13Jasitdecaystoitsgroundstate.TheinitialmassoftheexcitednucleusisMi.ThefinalmassofthenucleusafterdecayisclosesttoA. Mi–4×10
–30kgB. Mi–8×10
–30kgC. MikgD. Mi+4×10
–30kg
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SECTION B – continued
Question 1 (3marks)Asmallspherecarryingachargeof–2.7µCisplacedbetweenchargedparallelplates,asshownin Figure1.Thepotentialdifferencebetweentheplatesissetat15.5V,whichjustholdsthespherestationary.Theelectricfieldbetweentheplatesisuniform.
–2.7 μC
Figure 1
a. Inwhichdirection(up,down,right,left)willthespheremoveifthevoltageisincreased? 1mark
b. Calculatethevalueoftheelectricforcethatisholdingthespherestationaryiftheplatesare2.0mmapart.Showyourworking. 2marks
N
SECTION B
Instructions for Section BAnswerallquestionsinthespacesprovided.Whereananswerboxisprovided,writeyourfinalanswerinthebox.Ifananswerboxhasaunitprintedinit,giveyouranswerinthatunit.Inquestionswheremorethanonemarkisavailable,appropriateworkingmustbeshown.Unlessotherwiseindicated,thediagramsinthisbookarenotdrawntoscale.Takethevalueofgtobe9.8ms–2.
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SECTION B – continuedTURN OVER
Question 2 (8marks)AnelectronisacceleratedfromrestbyapotentialdifferenceofV0.Itemergesataspeedof 2.0×107ms–1intoamagneticfield,B,ofstrength2.5×10–3Tandfollowsacirculararc, asshowninFigure2.
V0
electronsource
B = 2.5 × 10–3 T
Figure 2
a. Calculatethevalueoftheacceleratingvoltage,V0 .Showyourworking. 3marks
kV
b. Explainwhythepathoftheelectroninthemagneticfieldfollowsacirculararc. 2marks
c. Calculatetheradiusofthepathtravelledbytheelectron.Showyourworking. 3marks
m
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SECTION B – Question 3–continued
Question 3 (6marks)ThemotionofEarth’smooncanbemodelledasacircularorbitaroundEarth,asshowninFigure3.
moon
Earth
Figure 3
Data
massofEarth 5.98×1024kg
massofthemoon 7.35×1022kg
radiusofthemoon’sorbitaroundEarth 3.84×108m
universalgravitationalconstant(G) 6.67×10–11Nm2kg–2
a. CalculatethemagnitudeofthegravitationalforcethatEarthexertsontheorbitingmoon.Giveyouranswercorrecttothreesignificantfigures.Showyourworking. 3marks
N
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SECTION B – continuedTURN OVER
b. TheaverageorbitalperiodofEarth’smoonis27.32days.ThemoonismovingslightlyfurtherawayfromEarthatanaveragerateof4cmperyear.
Giventhisinformation,willtheaverageorbitalperiodofEarth’smoondecrease,staythesameorincrease?Explainyouranswer. 3marks
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SECTION B – continued
Question 4 (3marks)Figure4showsaschematicdiagramofasimpleone-coilDCmotor.Acurrentisflowingthroughthecoil.
split-ring commutator
DC power supply
K L
J M
+ –
N S
Figure 4
a. DrawanarrowonFigure4toindicatethedirectionoftheforceactingonthesideJKof thecoil. 1mark
b. Explainthepurposeofthesplit-ringcommutator. 2marks
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SECTION B – continuedTURN OVER
Question 5 (3marks)Physicsstudentswhoareinvestigatingthegenerationofelectricityspinacoilataconstant10rotations persecondinauniformmagneticfield.Theyobservetheoutputonanoscilloscope.Theexperimentalset-upisshowninFigure5.Thepeakvoltageproducedbythecoilis5mV.
SN
Figure 5
Ontheaxesbelow,sketchthevoltageversustimegraphobservedonthescreenoftheoscilloscopeforonecompleterotationofthecoilfromthepositionshowninFigure5.Includeappropriatescalesoneachaxis.
V (mV)
t (s)
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SECTION B – Question 6–continued
Question 6 (7marks)GirandKauareinvestigatingelectromagneticinduction.TheyhaveasinglewireloopofdimensionsXY=0.030mlongandYZ=0.020mwide,whichisplacedinauniformmagneticfieldofstrength0.20T.Theloopisrotatedclockwiseaboutanaxis,asshowninFigure6.
N S
X
Y
W
Z
BA
sliprings
axis
Figure 6
a. ExplainthepurposeoftheslipringsintheapparatusshowninFigure6. 2marks
b. Calculatethesizeofthemagneticfluxthroughtheloopwhenitisorientedasshownin Figure6.Showyourworking. 2marks
Wb
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SECTION B – continuedTURN OVER
TheloopisrotatedbyKauataconstantfrequency,f,andanEMF,ε,isgenerated.Figure7showsthegeneratedEMFversustimetraceobservedonthescreenofanoscilloscope.
0.1 0.2 0.3 0.4
ε (mV)
t (s)
1086420
–2–4–6–8
–10
Figure 7
c. CalculatethefrequencyoftherotationfromtheoscilloscopetraceshowninFigure7. 1mark
Hz
d. Girnowdoublesthenumberofturnsintheloopfromoneturntotwoturns,creatingtwoloops.Theloopsareagainrotatedatthesameconstantfrequency,f.
OnFigure8below,sketchagraphthatshowstheresultingvariationoftheEMFwithtimebetweenpointsAandB,aslabelledinFigure6.Theoriginaloutputisshownasadashedline. 2marks
0.1 0.2 0.3 0.4
ε (mV)
t (s)
1086420
–2–4–6–8
–10
Figure 8
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SECTION B – Question 7–continued
Question 7 (10marks)AngelaandJanekareinstallingtwolow-voltagelightsintheiroutdoorgarden.Theyhavea 240VRMSACtransformerwithanoutputvoltageof12VRMSAC.Eachlighthasaconstantresistanceof6.0Ω.Forthepurposesofcalculations,assumethatthetransformerisideal.
a. Describewhatismeantbyanidealtransformerintermsoftheinputpowerandtheoutputpower. 1mark
b. Calculatetheratioofthenumberofturnsoftheprimarycoiltothenumberofturnsofthesecondarycoil. 1mark
c. Eachlightisdesignedtooperateat12VRMS.
Calculatethepowerdissipatedinonelightwhenitisoperatedat12VRMS.Showyourworking. 2marks
W
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SECTION B – continuedTURN OVER
AngelaandJaneknowconnectthefirstlight,Light1,tothetransformerusingtwowires,each 12.0mlong,asshowninFigure9.Eachwirehasaresistanceof0.05Ωpermetre.
12.0 m
Light 1 12 VRMS AC
transformer
240 VRMS AC
Figure 9
d. CalculatetheRMSvoltageacrossLight1.Showyourworking. 3marks
V
e. AngelaandJaneknowconnectthesecondlight,Light2,directlyacrossthesecondaryofthetransformer,asshowninFigure10.
12.0 m
Light 1Light 2
transformer
Figure 10
TheythoughtthatwiththecircuitshowninFigure10,Light1andLight2wouldbeequallybright.However,theyobservedthatLight2wasbrighterthanLight1.
ExplainwhyLight2wasobservedtobebrighterthanLight1. 3marks
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SECTION B – Question 8–continued
Question 8 (8marks)Acarisdrivingupauniformslopewithatrailerattached,asshowninFigure11.Theslopeisangledat15°tothehorizontal.Thetrailerhasamassof200kgandthecarhasamassof750kg.Ignoreallretardingfrictionforcesdowntheslope.
15°
carcoupling
trailer
Figure 11
a. OnFigure12below,drawlabelledarrowstoindicatethedirectionoftheforcesactingonthetrailer.Thelabelsshouldalsoindicatethekindofforcethateacharrowrepresents. 3marks
trailer
15°
Figure 12
b. Thecarandtraileraretravellingataconstantspeedof8ms–1uptheslope.
Calculatethemagnitudeoftheforcethatthecarexertsonthetrailer.Showyourworking. 2marks
N
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SECTION B – continuedTURN OVER
c. Calculatethegravitationalpotentialenergygainedbythecarandtrailerwhentheyhavetravelled100malongtheslope.Showyourworking. 3marks
kJ
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SECTION B – Question 9–continued
Question 9 (10marks)Inamodelofaproposedrideatathemepark,a5.0kgsmoothblockslidesdownarampfrompointWandintoanidealspringbumperwithoutanyfrictionorairresistance,asshowninFigure13. Thefinalsectionoftheramp,betweenpointsXandY,ishorizontal.TheblockcomestoaninstantaneousstopatpointY.
block
X
W
h
ideal spring bumper
Y
Figure 13
a. DescribetheaccelerationoftheblockatpointsW,XandY. 4marks
b. Themaximumcompressionofthespringismeasuredas3.0manditsspringconstant,k,is100Nm–1.
Calculatethereleaseheight,h.Showyourworking. 3marks
m
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SECTION B – continuedTURN OVER
c. Calculatethemagnitudeofthemaximummomentumoftheblock.Showyourworking. 2marks
kgms–1
d. Whentheblockcomestorest,itsmomentumiszero.
Intermsoftheprincipleofconservationofmomentum,statewhathashappenedtothemomentumoftheblockasitcomestorest. 1mark
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SECTION B – continued
Question 10 (4marks)JacintaisstandingstillwhileobservingaspaceshippassingEarthataspeedof0.984c.
a. Calculateγforthisspeed,correcttothreesignificantfigures.Showyourworking. 2marks
b. ThespaceshipistravellingtotheAlphaCentauristarsysteminastraightlineatthisspeed.InJacinta’sframeofreference,thisdistanceismeasuredtobe4.37light-years(thatis,itwouldtakelight4.37yearstotravelthisdistance).
CalculatethetimethatwouldbemeasuredbyJacintaforthespaceship’sjourney,correcttothreesignificantfigures.Showyourworking. 2marks
years
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SECTION B – continuedTURN OVER
Question 11 (4marks)Atransversewaveistravellingthroughamedium,asshowninFigure14.Thefrequencyofthesourceproducingthewaveis40Hzandthewavetravelsataspeedof35ms–1.Theamplitudeofthewaveis0.50m.
35 m s−1P
Figure 14
a. WhatistheperiodofoscillationforpointPinFigure14? 1mark
ms
b. Ontheaxesbelow,sketchthedisplacementversustimegraphforthepointPofthistransversewave,showingatleasttwocompletecycles.Includescalesandunitsoneachaxis. 3marks
displacement
time
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SECTION B – continued
Question 12 (5marks)Studentsaretestingtwoidenticalradiotransmitters,R1andR2,onafootballfield.Thetransmittersarepositioned24mapart,asshowninFigure15.Thetransmittersareinphase,bothemittingcrestssimultaneously,andemitwavesofwavelength18minalldirections.ThestudentsarestandingatpointX,whichislocated72mawayfromthenearesttransmitter,R1.
R1
R2
24 m
X
Y
72 m
Figure 15
a. Duringtesting,theradiosignalreceivedatpointXisdetectedtobeaminimum.
CalculatetheshortestdistancethatpointXcouldbefromR2.Showyourworking. 2marks
m
b. Atanotherlocationonthefootballfield,pointY,thestudentsdetectamaximum.
ExplainwhythetwoobservationsatpointsXandYwouldsupportthewavemodeloflight. 3marks
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SECTION B – continuedTURN OVER
Question 13 (4marks)Theboundarybetweentwotransparentmaterials,Medium1andMedium2,eachhavingdifferentrefractiveindices,isshowninFigure16.Anincidentrayatanangleθiisalsoshown.
θi
normal
Medium 1, n = 1.56 Medium 2, n = 1.42
Figure 16
a. TherefractedrayappearsinMedium2.
SketchtheapproximatedirectionoftherefractedrayinMedium2onFigure16. 1mark
b. Whatrangeofincidentangles,θi,wouldresultinalightrayemerginginMedium2?Showyourworking. 3marks
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SECTION B – continued
Question 14 (2marks)Toexplaindifferentaspectsofmechanicalwaves,aPhysicsteachersetsupademonstrationinaPhysicslaboratoryusinga0.80mwideloudspeakerandamicrophone.ThemicrophonemeasuresthesoundintensityatdifferentpositionsonacirclearoundthespeakerfrompositionAtopositionB,asshowninFigure17.
A B
loudspeaker
Figure 17
ThespeedofsoundinthePhysicslaboratoryis334ms–1.Measurementsaremadeatfrequenciesof100Hzand10000Hz.Theloudspeakeremitsthe100Hzand10000Hzfrequencieswithequalintensity.Figure18showstheintensity,I,measuredforeachfrequencyatpositionsonthesemicircularlineshowninFigure17betweenpositionsAandB.
I 10000 Hz
100 Hz
A B
Figure 18
Explainwhytheresponseat10000Hzhasagreaterintensitydirectlyinfrontoftheloudspeaker,whiletheresponseat100Hzisnearlythesameatallpositions.
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SECTION B – continuedTURN OVER
Question 15 (7marks)TheapparatusshowninFigure19isusedtoinvestigatethephotoelectriceffect.Lightofvariouswavelengthsisshoneontoasilverplate(cathode).Theworkfunctionofsilveris4.9eV.
V
µA
cathode
light
vacuum
photoelectron
battery
anode
Figure 19
a. Explainwhathappenswhenlightofwavelength400nmhitsthesilverplate.Usecalculationstosupportyouranswer. 2marks
b. Explainwhathappenswhenlightwithaphotonenergyof5.4eVhitsthesilverplate. 2marks
c. Whichmodeloflightdoesthisphotoelectricinvestigationsupport?Givetworeasonstojustifyyouranswer. 3marks
Modeloflight
1.
2.
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SECTION B – continued
Question 16 (6marks)X-raysofwavelength2.0nmareemittedfromanX-raysource.
a. CalculatetheenergyofonephotonoftheseX-rays.Showyourworking. 3marks
eV
b. The2.0nmX-raysareincidentonasinglenarrowslitofwidth5×10–8m.
Wouldadiffractionpatternbeobserved?Justifyyouranswer. 3marks
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SECTION B – continuedTURN OVER
Question 17 (5marks)Lightfromamercuryvapourlampshowsalinespectrumrelatedtodiscreteenergylevels.SomeoftheenergylevelsforthemercuryatomareshowninFigure20.
ionisation10.48.8
6.7
4.9
0
n = 4
n = 3
n = 2
ground state n = 1
energy (eV)
Figure 20
a. DrawanarrowonFigure20toindicatethetransitionbetweenthelistedenergystatesthatwouldproducethelowestfrequencyofanemittedphoton. 1mark
b. Calculatetheenergyofthelightemittedwhenthemercuryatommakesatransitionfromthethirdenergylevel(n =3)toitsgroundstate(n =1).Showyourworking. 2marks
J
c. Explainwhathappenstoamercuryatominitsgroundstateifaphotonofenergy2.1eVisincidentonit. 2marks
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SECTION B – Question 18–continued
Question 18 (15marks)Asmallrubberballofmass50gfallsverticallyfromagivenheightandreboundsfromahardfloor.Theball’sspeedimmediatelybeforeimpactis3.6ms–1.Theballreboundsupwardataspeedof3.3ms–1immediatelyafteritleavesthefloor.Theballisincontactwiththefloorfor40ms.
a. Calculatethemagnitudeanddirectionofthenetaverageforceactingonthe50gballwhileitisincontactwiththefloor.Showyourworking. 4marks
N
b. Justbeforetheballhitsthefloor,ithasacertainamountofkineticenergy,Ek. Atoneinstantwhentheballisincontactwiththefloor,itisstationarybeforeitrebounds.
Explainwhathashappenedtothekineticenergy,Ek,oftheballwhenitisstationary. 2marks
c. Justbeforetheballhitsthefloor,ithasacertainamountofverticalmomentum,p. Atoneinstantwhentheballisincontactwiththefloor,itisstationarybeforeitrebounds.
Whathashappenedtotheverticalmomentum,p,oftheballwhenitisstationary? 1mark
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Duringtheirpracticalinvestigation,somePhysicsstudentsinvestigatethemovementofasmallrubberball.Theballfallsfromaheightof1.00mandreboundstoaheightof0.78m.Thestudentsrecordtheball’sverticalpositionversustimebyusingasmartphone’svideofeatureandametrerulescale.Theuncertaintyintheball’sverticalpositionis±0.03m.Theresultsfromthestudents’recordeddataareplottedonthegraphinFigure21.
0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90
1.20
1.00
0.80
0.60
0.40
0.20
0.00
Figure 21
d. OnthegraphinFigure21:• labeleachaxisandincludeunitsoneachaxis• insertappropriateuncertaintybarsfortheheightvaluesonthegraph,forthereadingsfor
thefirstfourdatapointsaftertheballisreleased• drawsmoothcurvesofbestfit. 5marks
e. EstimatethespeedoftheballattheinstantofimpactusinganappropriategradientofthegraphinFigure21.Usecalculationstosupportyouranswer. 3marks
ms–1
END OF QUESTION AND ANSWER BOOK
Victorian Certificate of Education 2021
PHYSICS
Written examination
FORMULA SHEET
Instructions
This formula sheet is provided for your reference.A question and answer book is provided with this formula sheet.
Students are NOT permitted to bring mobile phones and/or any other unauthorised electronic devices into the examination room.
© VICTORIAN CURRICULUM AND ASSESSMENT AUTHORITY 2021
PHYSICS FORMULA SHEET 2
Physics formulas
Motion and related energy transformations
velocity; acceleration v st
a vt
� ���
��
;
equations for constant acceleration
v u at
s ut at
s vt at
v u as
s v u t
� �
� �
� �
� �
� �� �
1212
212
2
2
2 2
Newton’s second law ΣF = ma
circular motion a vr
rT
� �2 2
24�
Hooke’s law F = –kΔ x
elastic potential energy12
k(Δ x)2
gravitational potential energy near the surface of Earth mgΔh
kinetic energy12
2mv
Newton’s law of universal gravitation F G m mr
= 1 22
gravitational field g G Mr
= 2
impulse FΔ t
momentum mv
Lorentz factor� �
�
1
12
2vc
time dilation t = toγ
length contraction L L� o�
rest energy Erest = mc2
relativistic total energy Etotal = γmc2
relativistic kinetic energy Ek = (γ – 1)mc2
3 PHYSICS FORMULA SHEET
TURN OVER
Fields and application of field concepts
electric field between charged plates E Vd
=
energy transformations of charges in an electric field
12
2mv qV=
field of a point charge E kqr
= 2
force on an electric charge F = qE
Coulomb’s law F kq qr
= 1 22
magnetic force on a moving charge F = qvB
magnetic force on a current carrying conductor F = nIlB
radius of a charged particle in a magnetic field r mvqB
=
Generation and transmission of electricity
voltage; power V = RI; P = VI = I2R
resistors in series RT = R1 + R2
resistors in parallel1 1 1
1 2R R RT� �
ideal transformer actionVV
NN
II
1
2
1
2
2
1= =
AC voltage and current V VRMS peak=12
I IRMS peak=12
electromagnetic induction Β ΒEMF: flux:N B A
tΦε Φ ⊥
∆= − =
∆
transmission losses Vdrop = Iline Rline Ploss = I 2line Rline
Wave concepts
wave equation v = f λ
constructive interference path difference = nλ
destructive interference path difference � ����
���n 1
2�
fringe spacing �x Ld
��
Snell’s law n1 sinθ1 = n2 sinθ2
refractive index and wave speed n1 v1 = n2 v2
PHYSICS FORMULA SHEET 4
END OF FORMULA SHEET
The nature of light and matter
photoelectric effect E hfk max � ��
photon energy E = hf
photon momentum p h��
de Broglie wavelength � �hp
Data
acceleration due to gravity at Earth’s surface g = 9.8 m s–2
mass of the electron me = 9.1 × 10–31 kg
magnitude of the charge of the electron e = 1.6 × 10–19 C
Planck’s constant h = 6.63 × 10–34 J s h = 4.14 × 10–15 eV s
speed of light in a vacuum c = 3.0 × 108 m s–1
universal gravitational constant G = 6.67 × 10–11 N m2 kg–2
mass of Earth ME = 5.98 × 1024 kg
radius of Earth RE = 6.37 × 106 m
Coulomb constant k = 8.99 × 109 N m2 C–2
Prefixes/Units
p = pico = 10–12 n = nano = 10–9 μ = micro = 10–6 m = milli = 10–3
k = kilo = 103 M = mega = 106 G = giga = 109 t = tonne = 103 kg
