【MOOC】College Physics I-Dalian University of Technology 中国大学慕课MOOC答案

【MOOC】CollegePhysicsI-DalianUniversityofTechnology中国大学慕课MOOC答案Pre-coursepreparation1、【判断题】Velocityinphysicsisthespeedofanobject.本题答案：【错误】2、【判断题】Accelerationisdefinedasavectorquantitythatindicatestherateofchangeofvelocity.本题答案：【正确】3、【判断题】Distanceanddisplacementaretwoquantitiesthatmayseemtomeanthesamethingyethavedifferentdefinitionsandmeanings.本题答案：【正确】UnitTest11、【单选题】Whichofthefollowingisavectorquantity:本题答案：【acceleration】2、【单选题】Inrighthandedcoordinatesystemwhichaxisisconsideredtobepositive?本题答案：【Thethumbisz-axis,fingerscurledfromx-axistoy-axis】3、【单选题】WhatisthemagnitudeoftheCartesianvectorhavingthex,yandzaxiscomponentstobeA,BandC?本题答案：【SquarerootofthesquareseachA,BandC】4、【单选题】Theradialcomponentofvelocityforaparticlemovinginacircularpathis______.本题答案：【Zero】5、【单选题】Whenaccelerationis_______,avelocityofaparticleisconstant.本题答案：【Zero】6、【单选题】Ablockslidingdownaninclinedplanehasacceleration_________accelerationduetogravity.本题答案：【Lessthan】7、【单选题】Aphysicsprofessorleavesherhouseandwalksalongthesidewalktowardcampus.After5minitstartstorainandshereturnshome.HerdistancefromherhouseasafunctionoftimeisshowninFig.AtPoint_________(fillinthelabeledpointsI/II/III/IV/V)ishervelocityzero.本题答案：【IV】8、【单选题】Aphysicsprofessorleavesherhouseandwalksalongthesidewalktowardcampus.After5minitstartstorainandshereturnshome.HerdistancefromherhouseasafunctionoftimeisshowninFig.AtPoint_________(fillinthelabeledpointsI/II/III/IV/V)ishervelocityincreasinginmagnitude.本题答案：【II】9、【单选题】Amodelofahelicopterrotorhasfourblades,each3.40mlongfromthecentralshafttothebladetip.Themodelisrotatedinawindtunnelat550rev/min.Thelinearspeedofthebladetipis________m/s.本题答案：【196m/s】10、【单选题】AnastronauthaslefttheInternationalSpaceStationtotestanewspacescooter.Herpartnermeasuresthefollowingvelocitychanges,takingplaceina10sinterval.Atthebeginningsheismovingtowardtherightat15.0m/s,andattheendsheismovingtowardtheleftat15.0m/s.Themagnitudeofheraverageaccelerationis________m/s^2.本题答案：【3】11、【单选题】Abodythat’smovingwithaconstantspeedtravelsoncearoundacircularpath.Whichofthefollowingis/aretrueconcerningthemotion?I.Thedisplacementiszero.II.Theaveragespeediszero.III.Theaccelerationiszero.本题答案：【Ionly】12、【单选题】Arockisthrownoffa35mcliffata45°angleabovethehorizontal.Whichisthefollowingistrueregardingtheaccelerationoftherock?本题答案：【Theaccelerationwillbeofmagnitudegandinadownwarddirection.】13、【单选题】Asmallstoneisthrownhorizontallywithaninitialspeedof30m/sfromabridge.Findthestone’stotalspeedwhenitentersthewater4secondslater.(Ignoreairresistance.)本题答案：【50m/s】14、【单选题】Whichoneofthefollowingstatementsistrueconcerningthemotionofanidealprojectilelaunchedatanangleof45°tothehorizontal?本题答案：【Theverticalspeeddecreasesonthewayupandincreasesonthewaydown.】15、【单选题】Thepositionofanobjectmovinginastraightlineisgivenbytheequationx=(3t3+7t+5)m,wheretisinseconds.Whatistheobject’saccelerationattimet=5seconds?本题答案：【90m/s2】16、【单选题】Theearthhasaradiusof6380kmandturnsaroundonceonitsaxisin24h.Whatistheradialaccelerationofanobjectattheearth’sequator?_______m/s2本题答案：【0.034】17、【单选题】Theearthhasaradiusof6380kmandturnsaroundonceonitsaxisin24h.Ifaradattheequatorisgreaterthang,objectswillflyofftheearth’ssurfaceandintospace.Whatwouldtheperiodoftheearth’srotationhavetobeforthistooccur?本题答案：【5070S#1.4h】18、【单选题】Aballisprojectedwithaninitialvelocityofmagnitudev0=40m/stowardaverticalwallasshowninthefigure.Howlongdoestheballtaketoreachthewall?______S本题答案：【1.0】19、【单选题】Twoprojectilesarelaunchedat100m/s,theangleofelevationforthefirstbeing30°andforthesecond60°.Whichofthefollowingstatementsisfalse?本题答案：【Alloftheotherstatementsarefalse.】20、【单选题】PlaneAisflyingat400mphinthenortheastdirectionrelativetotheearth.PlaneBisflyingat500mphinthenorthdirectionrelativetotheearth.WhatisthespeedofPlaneBasobservedfromPlaneA?本题答案：【357mph】Pre-coursepreparation1、【判断题】Equilibriumistheconditionofasystemwhenneitheritsstateofmotionnoritsinternalenergystatetendstochangewithtime.本题答案：【正确】2、【判断题】Todescribeaforce,weonlyneedtodescribethemagnitudethatdescribehowhardtheforcepushesorpulls.本题答案：【错误】3、【判断题】Inclassicalmechanicskinematicsgenerallyreferstothestudyofpropertiesofmotion--position,velocity,acceleration.Dynamicsisthestudyofthephysicsofmotionandhowitrelatestoappliedforces.本题答案：【正确】UnitTest21、【单选题】Ifanobjectisinequilibrium,whichofthefollowingstatementsisnottrue?本题答案：【Theobjectmustbeatrest.】2、【单选题】Twoblocks,joinedbyastring,havemassesof6.0kgand9.0kg.Theyrestonafrictionlesshorizontalsurface.Asecondstring,attachedonlytothe9kgblock,hashorizontalforce=30Nappliedtoit.Bothblocksaccelerate.Findthetensioninthestringbetweentheblocks.本题答案：【12N】3、【单选题】Ifanobjectofmassmmoveswithconstantvelocityv,thenetforceontheobjectis本题答案：【0】4、【单选题】Alargecrateofmassmisplacedonthebackofatruckbutnottieddown.Asthetruckacceleratesforwardwithanaccelerationa,thecrateremainsatrestrelativetothetruck.Whatforcecausesthecratetoaccelerateforward?本题答案：【theforceoffrictionbetweenthecrateandthefloorofthetruck】5、【单选题】Ifduringagivenphysicalprocesstheonlyforceactingonanobjectisfriction,whichofthefollowingmustbeassumedinregardtotheobject'skineticenergy?本题答案：【Itcannotbedeterminedfromtheinformationgiven】6、【单选题】Whichofthefollowingisthatformofenergyassociatedwithanobject'smotion?本题答案：【Kinetic】7、【单选题】Theworkdonebystaticfrictioncanbe:本题答案：【Anyoftheothers】8、【单选题】Thequantityofworkequaltoonejouleisalsoequivalenttowhichofthefollowing?本题答案：【Watt?s】9、【判断题】OnekilogramofgoldwouldhavegreatervalueonEarththanontheMoon.本题答案：【错误】10、【判断题】Anobjectcanmoveevenwhennoforceactsonit.本题答案：【正确】Pre-Coursepreparation1、【判断题】Workisascalarquantity,eventhoughit'scalculatedbyusingtwovectorquantities(forceanddisplacement).本题答案：【正确】2、【判断题】Workandpoweraresamethingsincebothoftheminvolvetheamountofenergytransferred.本题答案：【错误】3、【判断题】Conservationmeansthepreservationofaphysicalquantityduringtransformationsorreactions.本题答案：【正确】Unittest31、【单选题】Aboycaughtaballofmass200gmovingwithaspeedof30m/s.Ifthecatchingprocessbecompletedin0.1s,theaveragenetforceofimpactexertedbytheballonthehandsoftheboyis本题答案：【60N】2、【单选题】AlexandJohnareloadingidenticalcabinetsontoatruck.Alexliftshiscabinetstraightupfromthegroundtothebedofthetruck,whereasJohnslideshiscabinetuparoughramptothetruck.Whichstatementiscorrectabouttheworkdoneonthecabinet–Earthsystem?本题答案：【JohndoesmoreworkthanAlex.】3、【单选题】Aballofclayfallsfreelytothehardfloor.Itdoesnotbouncenoticeably,anditveryquicklycomestorest.What,then,hashappenedtotheenergytheballhadwhileitwasfalling?本题答案：【Itisintheballandfloor(andwalls)asenergyofinvisiblemolecularmotion.】4、【单选题】Iftwoparticleshaveequalmomentum,aretheirkineticenergiesequal?本题答案：【no,exceptwhentheirspeedsarethesame】5、【单选题】Anatomicnucleussuddenlyburstsapart(fissions)intotwopieces.Onepiecetravelsoffthetheleftandanotherpiecetravelsofftotheright.Thelighterfragmenthas________speed.本题答案：【greater】6、【单选题】Atoneinstant,thecenterofmassofasystemoftwoparticlesislocatedonthex-axisatx=2.0m.Oneoftheparticlesisattheorigin.Theotherparticlehasamassof0.10kgandisatrestonthex-axisatx=8.0m.Themassoftheparticleattheoriginis(kg).本题答案：【0.3】7、【单选题】Idropa60-ggolfballfrom2.0mhigh.Itreboundsto1.5m.Howmuchenergyislost?本题答案：【0.29J】8、【单选题】Agirlandherbicyclehaveatotalmassof40kg.Atthetopofthehillherspeedis5.0m/s.Thehillis10mhighand100mlong.Iftheforceoffrictionassheridesdownthehillis20N,whatisherspeedatthebottom?本题答案：【11m/s】9、【单选题】Ablockisprojectedwithspeedvacrossahorizontalsurfaceandslidestoastopduetofriction.Thesameblockisthenprojectedwiththesamespeedvupaninclinewhereisslidestoastopduetofriction.Inwhichcasedidthetotalmechanicalenergyoftheblockdecreasetheleast?本题答案：【Thecaseontheinclinedsurfacehadtheleastdecreaseintotalmechanicalenergy.】10、【单选题】Whichofthefollowingisanexampleofanonconservativeforce?本题答案：【frictiontionalforce】Pre-coursepreparation1、【判断题】Abodyissaidtobearigidbody,whenithasperfectlydefiniteshapeandsize.Thedistancebetweenallpointsofparticlesofsuchabodydonotchange,whileapplyinganyforceonit本题答案：【正确】2、【判断题】Thereare2πradiansinonecompleterevolution.本题答案：【正确】3、【判断题】Torqueisameasureoftheforcethatcancauseanobjecttorotateaboutanaxis.本题答案：【正确】Unittest41、【单选题】Agrindstoneincreasesinangularspeedfrom4.00rad/sto12.00rad/sin4.00s.Throughwhatangledoesitturnduringthattimeintervaliftheangularaccelerationisconstant?本题答案：【32.0rad】2、【单选题】Consideranobjectonarotatingdiskadistancerfromitscenter,heldinplaceonthediskbystaticfriction.Whichofthefollowingstatementsisnottrueconcerningthisobject?本题答案：【Iftheangularspeedisconstant,theobjectisnotaccelerated.】3、【单选题】Aconstantnettorqueisexertedonanobject.Whichofthefollowingquantitiesfortheobjectcannotbeconstant?本题答案：【kineticenergy】4、【单选题】AsolidaluminumsphereofradiusRhasmomentofinertiaIaboutanaxisthroughitscenter.Willthemomentofinertiaaboutacentralaxisofasolidaluminumsphereofradius2Rbe本题答案：【32I】5、【单选题】Aniceskaterstartsaspinwithherarmsstretchedouttothesides.Shebalancesonthetipofoneskatetoturnwithoutfriction.Shethenpullsherarmsinsothathermomentofinertiadecreasesbyafactorof2.Intheprocessofherdoingso,whathappenstoherkineticenergy?本题答案：【Itincreasesbyafactorof2.】6、【单选题】Consideranisolatedsystemmovingthroughemptyspace.Thesystemconsistsofobjectsthatinteractwitheachotherandcanchangelocationwithrespecttooneanother.Whichofthefollowingquantitiescanchangeintime?本题答案：【Neithertheangularmomentumnorlinearmomentumofthesystem.】7、【单选题】Twoponiesofequalmassareinitiallyatdiametricallyoppositepointsontherimofalargehorizontalturntablethatisturningfreelyonafrictionless,verticalaxlethroughitscenter.Theponiessimultaneouslystartwalkingtowardeachotheracrosstheturntable.Astheywalk,whathappenstotheangularspeedoftheturntable?本题答案：【Itincreases.】8、【单选题】Aturntablerotateswithaconstantangularacceleration.After4.00sithasrotatedthroughanangleof60.0rad.Theangularvelocityofthewheelatthebeginningofthe4.00sintervalwas本题答案：【10.5rad/s】9、【单选题】Asolid,uniformcylinderwithmass8.25kganddiameter15.0cmisspinningat220rpmonathin,frictionlessaxlethatpassesalongthecylinderaxis.Youdesignasimplefrictionbraketostopthecylinderbypressingthebrakeagainsttheouterrimwithanormalforce.Thecoefficientofkineticfrictionbetweenthebrakeandrimis0.333.Whatmusttheappliednormalforcehetobringthecylindertorestafterithasturnedthrough5.25revolutions?本题答案：【7.47N】10、【单选题】Twoparticlesofdifferentmassstartfromrest.Thesamenetforceactsonbothofthemastheymoveoverequaldistances.Howdotheirfinalkineticenergiescompare?本题答案：【Theparticleshaveequalkineticenergies.】Pre-coursepreparation1、【判断题】RelativitygenerallyreferstotwotheoriesofAlbertEinstein,hisSpecialTheoryofRelativityandhisGeneralTheoryofRelativity.本题答案：【正确】2、【判断题】Specialrelativitycannotbeappliedtoclassicalmechanicsproblems.本题答案：【错误】3、【判断题】SpecialtheoryofrelativitybyEinstein(1905)providesextremelyaccurateresultsaslongasthedomainofstudyisrestrictedtolargeobjectsandthespeedsinvolveddonotapproachthespeedoflight.本题答案：【错误】Unittest51、【单选题】Inordertoreduceyourthicknessby40%toanobserveratrest,whatisthespeedwithwhichyoumustbemovingrelativetotheobserver?本题答案：【0.8c】2、【单选题】Toappeartobethintoobserversatrest,ayoungmanstartsridingaspacecraft.Toreducehisthicknessexactlybyhalf,thespeedatwhichthespacecraftmustmoveis本题答案：【0.866c】3、【单选题】Inthelaboratoryframeofreference,themomentumofaparticleofrestmassmisfoundtobe4mc/3withcthespeedoflightinvacuum.Whatisthespeedoftheparticleinthelaboratoryframeofreference?本题答案：【4c/5】4、【单选题】Whichstatementiscorrectaboutthespecialrelativity?本题答案：【Thespeedoflighthasnothingtodowiththereferencesystem.】5、【单选题】AspacecraftzoomspasttheEarthwithaconstantvelocity.AnobserverontheEarthmeasuresthatanundamagedclockonthespacecraftistickingatonethirdtherateofanidenticalclockontheEarth.WhatdoesanobserveronthespacecraftmeasureabouttheEarth-basedclock’stickingrate?本题答案：【Itrunsatone-thirdtherateofhisown】6、【单选题】Anastronautistravelinginaspacecraftinouterspaceinastraightlineataconstantspeedof0.500c.Whichofthefollowingeffectswouldsheexperience?本题答案：【Noneofthoseanswersiscorrect.】7、【单选题】Adistantastronomicalobject(aquasar)ismovingawayfromusathalfthespeedoflight.Whatisthespeedofthelightwereceivefromthisquasar?本题答案：【c】8、【单选题】AspacecraftbuiltintheshapeofaspheremovespastanobserverontheEarthwithaspeedof0.500c.Whatshapedoestheobservermeasureforthespacecraftasitgoesby?本题答案：【aroundpillowshape,flattenedalongthedirectionofmotion】9、【多选题】Asacarheadsdownahighwaytravelingataspeedvawayfromagroundobserver,whichofthefollowingstatementsaretrueaboutthemeasuredspeedofthelightbeamfromthecar’sheadlights?Morethanonestatementmaybecorrect.本题答案：【Thedrivermeasuresthelightspeedtobec#Thegroundobservermeasuresthelightspeedtobec】10、【多选题】Whichofthefollowingstatementsarefundamentalpostulatesofthespecialtheoryofrelativity?Morethanonestatementmaybecorrect.本题答案：【Thelawsofphysicsarethesameinallinertialreferenceframes.#Thespeedoflightisindependentoftheinertialreferenceframeinwhichitismeasured.】Pre-coursepreparation1、【判断题】Anexperimentshowsthatanelectronandapositroncanbeproducedafterahigh-energygammaraycollideswithahydrogenatom.Thisisanexperimentalevidenceforaviolationofprincipleofconservationofcharge.本题答案：【错误】2、【判断题】Atestchargeisapointchargeofaenoughsmallmagnitudeanditcanbeeitherpositiveornegative.本题答案：【正确】3、【判断题】Anelectricdipoleisapairofpointchargeswithequalmagnitudeandoppositesign(apositivechargeqandanegativecharge-q)separatedbyadistanced.Electricdipolemomentisascalarquantityandisdifinedasqd.本题答案：【错误】UnitTest61、【单选题】Electricchargeisdistributeduniformlyalonganinfinitelineinvacuum(thelinearchargedensityis).Theforceonatestchargeatadistancerfromthelineis().(isaunitvector.)本题答案：【】2、【单选题】Anelectricdipolewithdipolemomentisparalleltoalonglineofchargewithlinearchargedensityandatadistancefromtheline.Themagnitudeoftorqueonthedipoleequals().本题答案：【】3、【单选题】TwoparalleplateswithareaAaregivenchargesQuniformly.Theirseparationismuchsmallerthanthedimensionsoftheplatesandthefringingeffectisneglected.Whatisthemagnitudeoftheelectricforceononeplateexertedbytheother?本题答案：【】4、【单选题】Anelectricdipolewithdipolemomentisinauniformelectricfield.Ifthedipoleisinthestableequilibriumstate,whichofthefollowingstatementsiscorrect?本题答案：【Thetorqueiszeroandpotentialenergyisminimum.】5、【单选题】Achargeisplacedattheoriginofacoordinatesystemandachargeislocatedatonthex-axis.Theforceonisfoundtobe.Athirdchargeisnowplacedatonthex-axis.Whatisthenetforceonnow?本题答案：【】6、【单选题】Figureshowsaringofradiuswithanarrowgapof()andlinearchargedensity.ThemagnitudeoftheelectricfieldatthecenterOoftheringis（）.本题答案：【】7、【单选题】Anelectricdipolewithdipolemomentisplacednearalargeplanesheetwithasurfacechargedensity.Ifmakesanangleofwiththenormalofthesheet,themagnitudeofthetorqueexertedonthedipoleis().本题答案：【】8、【单选题】ThefourelectricdipolesareintheuniformelectricfieldinFigure.Whichoneisatthestableequilibriumstate?本题答案：【d】9、【单选题】Bycomparisonwiththeforceofgravity,theelectricalattractionbetweenanelectronandaproton本题答案：【isverymuchstonger.】10、【单选题】Twolightweightmetalspheresaresuspendedneareachotherfrominsulatingthreads.Onespherehasanetcharge;theotherspherehasnonetcharge.Thesphereswill本题答案：【attracteachother.】11、【填空题】Anelectricdipoleisplacedinauniformelectricfieldwithperpendicularto.Theworkdonebytheelectricfieldtotheelectricdipoleintheprocessthatrotatesfromtheorientationinthefiguretothedirectionofis_____.本题答案：【pE##%_YZPRLFH_%##Ep##%_YZPRLFH_%##p*E##%_YZPRLFH_%##E*p】12、【填空题】Inauniformelectricfield,anelectricdipolewithdipolemomentpointsinthedirectionoffield.Thetorqueonthedipoleis.本题答案：【0##%_YZPRLFH_%##zero】13、【填空题】Anelectricdipolewithdipolemomentisinauniformelectricfield.Whenthedipoleisintheunstableequilibriumstate,theanglebetweenandisindegree.本题答案：【180##%_YZPRLFH_%##180.##%_YZPRLFH_%##180.0】Pre-coursepreparation:conceptualunderstanding1、【判断题】GaussiansurfaceusedinGauss'slawisarealclosedsurfacewhichexistsinanelectricfield.本题答案：【错误】2、【判断题】Theelectricfluxisascalaranditmustbepositive.本题答案：【错误】3、【判断题】Gauss'slawprovidesarelationshipbetweentheelectricfieldonaclosedsurfaceandthechargedistributionwithinthatsurface.本题答案：【正确】UnitTest71、【单选题】Aconductingspherewithradiusandchargeisplacednearaverylargenonconductingplanesheetwithsurfacechargedensity.Undertheconditionofelectrostaticequilibrium,themagnitudeofelectricfieldatcenterofthesphereproducedbythechargeontheconductingsphereis本题答案：【】2、【单选题】FourpointchargesQ1,Q2,Q3,Q4areinspace.Sisaclosedsurface.EisthemagnitudeoftheelectricfieldatanarbitrarypointonsurfaceSanddenotestheelectricfluxthroughS.IfthechargeQ1ismovedfrompointatopointbalongthedashedline,whichofthefollowingstatementsistrue?本题答案：【EchangesbutFEdoesnotchange.】3、【单选题】Shownaretheelectricfieldlinesfortwopointchargeswithasmalldistancebapart.Theratioq1/q2equals本题答案：【-1/3】4、【单选题】InwhichofthefollowingcontextscanGauss’slawbeappliedtofindtheelectricfieldeasily?本题答案：【Apointverynearthesurfaceofalargeuniformlychargedplanesheet.】5、【单选题】ThreepointchargesQ1,Q2,Q3areinspace.Sisaclosedsurface.Q1isoutsideSwhileQ2andQ3areinside.EisthemagnitudeoftheelectricfieldatanarbitrarypointonsurfaceSanddenotestheelectricfluxthroughS.Whichofthefollowingstatementsiscorrect?本题答案：【EdependsonQ1,Q2,Q3whileFEdependsonQ2,Q3.】6、【单选题】AsshowninFigure,thefieldlinesdescribetheelectricfieldcausedbyachargedconductorinair.Throughcalculation,itisfoundthattheelectricfluxpassingthroughaclosedsurfaceAis.Thechargeontheconductoris().本题答案：【】7、【单选题】TheSIunitofelectricfluxis本题答案：【】8、【单选题】Apositivepointcharge+Qislocatedonthex-axisatx=a,andasecondnegativepointcharge-3Qislocatedonthex-axisatx=1.5a.AGaussiansurfacewithradiusr=2aiscenteredattheorigin.ThefluxthroughthisGaussiansurfaceis本题答案：【lessthanzero.】9、【判断题】Inacertainregionofspace,theelectricfieldisuniform.ItcanbeprovedthatthevolumechargedensityinthisregionmustbezerobasedontheGauss'slaw.本题答案：【正确】10、【判断题】Ifelectricfluxpassingthroughaclosedsurfaceiszero,tnechargedentsityeverywhereinsidetheclosedsurfacemustbezero.本题答案：【错误】11、【填空题】AcubehassidesoflengthL.ApointchargeQislocatedatthecenterofthecube.Theelectricfluxthroughoneofthesixfacesofthecubeis.(informoffraction：/)本题答案：【1/6】12、【填空题】ApointchargeqisplacedsomewherewithadistanceafromthecenterofasolidconductingsphereofradiusR,withaR.Thesphereiselectricallyneutral.Themagnitudeoftheelectricfieldatthespherecenteris______.本题答案：【0】13、【填空题】AsphericalsurfacewithradiusrisinaregionofuniformelectricfieldE.Theelectricfluxthroughthesurfaceis______.本题答案：【0】14、【填空题】Apointchargeqisplacedinsideacavitywithinaconductor.Theconductoriselectricallyneutralandisisolated.Thetotalchargeontheoutersurfaceoftheconductormustbe______.本题答案：【q】15、【填空题】AsshowninFigure,therearethreepointchargesinthespace,,,and.Sisaclosedsurface.Thepermittivityofvacuumis.TheelectricfluxthroughthesurfaceSis本题答案：【-1000000##%_YZPRLFH_%##-10^6##%_YZPRLFH_%##-1*10^6】Pre-coursepreparation:conceptualunderstanding1、【判断题】Electricpotentialenergyisakindofenergy.Soconsiderasystemofanelectricfieldandapointchargeinit,thesignofthepotentialenergyofthissystemisalwayspositive.本题答案：【错误】2、【判断题】Electronvolt(eV)isaunitofenergyandworklikeJoule.1eV=J.本题答案：【正确】3、【判断题】BothelectricfieldEandelectricpotentialVcandescribethecharacteristicsofafield.Iftheelectricpotentialatacertainpointiszero,theelectricfieldatthatpointhastobezero.本题答案：【错误】UnitTest81、【单选题】AconductingsphereAwithnegativecharge-QisconcentricwithanunchargedconductingsphericalshellB.EandVarethemagnitudesoftheelectricfieldandtheelectricpotentialatpointPinsidetheshell,respectively.Ifthepotentialisassumedtobezeroatinfinity,then本题答案：【E=0,V0.】2、【单选题】Apointcharge+Qisheldstationaryattheorigin.Asecondpointcharge-qmovesfromthepointr=atothepointr=2a.Howmuchworkisdonebytheelectricforceon-q?本题答案：【】3、【单选题】MovingapointchargeqalongtheaxisofachargedringwithradiusRandchargeQ.IfqismovedfromthecenterofringtopointPatadistancexfromthecenter,thentheworkdonebyelectricfieldforceonqequals().(Takepotentialtobezeroatinfinity.)本题答案：【】4、【单选题】Athininsulatingrodisbentintoasemicirculararcofradiusa,andatotalelectricchargeqisdistributeduniformlyalongtherod.Thepotentialatthecenterofcurvatureofthearcequals().(Thepotentialisassumedtobezeroatinfinity.)本题答案：【】5、【单选题】Aconductingspherewithnochargeisplacedbesideaverylargenonconductingplanesheetwithsurfacechargedensity.Undertheconditionofelectrostaticequilibrium,thepotentialatpointPonthesurfaceisV0asshownintheFigure.WhatarethemagnitudeofthefieldandthepotentialatthecenterO?本题答案：【E=0.V=V0.】6、【单选题】Aninfinitelineofchargehaslinearchargedensity.PointsAandBareatdistancesaandbfromtheline.IfapointchargetravelsslowlyfrompointAtopointB,thentheworkdonebytheexternalforceonitis.本题答案：【】7、【单选题】TheelectricpotentialVinacertainregionofspaceisgivenbyinSI.Theelectricfieldinvectorformatpoint(x,y,z)=(1,2,3)is()inSI.本题答案：【】8、【单选题】Inthecaseofachargedconductor,whatisthecharacteroftheconductor?本题答案：【Theelectricfieldmustbezeroeverywhereinsidetheconductor.】9、【单选题】Whichofthefollowinganglesbetweenanelectricdipolemomentandanappliedelectricfieldwillresultinthemoststablestate?本题答案：【0】10、【单选题】AsolidconductingsphereofradiusRiscenteredabouttheoriginofanxyz-coordinatesystem.AtotalchargeQisdistributeduniformlyonthesurfaceofthesphere.Assuming,asusual,thattheelectricpotentialiszeroataninfinitedistance,whatistheelectricpotentialatthecenteroftheconductingsphere?本题答案：【】11、【多选题】Eachofthefollowingpairsofchargesareseparatedbyadistanced.Whichpairhasthehighestpotentialenergy?本题答案：【+3Cand+5C#-3Cand-5C】12、【填空题】TheelectricpotentialVinaregionofspaceisgivenbyinSI,whereAisaconstant.Thex-componentofelectricfieldatpoint(x,y,z)=(2,0,2)is.本题答案：【-4A】13、【填空题】Figureshowsthreeequipotentialsurfacesinspace.AprotontravelsfrompointAtopointBalongthepathrepresentedbythesolidline.Theworkdonebytheelectricfieldontheprotonis______eV.本题答案：【40】Pre-coursepreparation:conceptualunderstanding1、【判断题】Twoobjectsseparatedbyaninsulatorhavetobechargedtoformacapacitor.本题答案：【错误】2、【判断题】Adielectricisanonconductingmaterial.本题答案：【正确】3、【判断题】Whenadielectricmaterialisputinanelectricfield,theinducedsurfacechargesariseasaresultofredistributionofpositiveandnegativechargewithinthedielectricmaterial,thephenomenoniscalledpolarization.本题答案：【正确】UnitTest91、【单选题】ThepotentialdifferenceVofaparallel-platecapacitorwithareaAandseparationdmaintainsunchanged.ThespacebetweentheplatesisfullyfilledwithadielectricofdielectricconstantKandresistivity.The“leakage”currentcarriedbythedielectricisgivenby().本题答案：【】2、【单选题】Aparallel-platecapacitorhaschargeQand-Qonitsplates.Onehalfofthegapbetweenthetwoplatesisfilledwithuniformdielectricwithpermittivityandtheotherhalfisfilledwithairasshowninthefigure.WhatistherelationbetweentheelectricfieldE0intheairandEinthedielectric?本题答案：【E0E.】3、【单选题】Aparallel-platecapacitorhaschargeQand-Qonitsplates.Onehalfofthegapbetweenthetwoplatesisfilledwithuniformdielectricwithpermittivityandtheotherhalfisfilledwithairasshowninthefigure.WhatistherelationbetweentheelectricfieldE0intheairandEinthedielectric?本题答案：【E0=E.】4、【单选题】Whichoneiscorrectaboutthecapacitanceofaparallel-platecapacitor?本题答案：【Itdependsontheplateseparation.】5、【单选题】AparallelplatecapacitorwithdielectrichasplatesofareaAandspacingofd.ThedielectrichasdielectricconstantKanddielectricstren