现代物理学智慧树知到课后章节答案2023年下苏州大学

现代物理学智慧树知到课后章节答案2023年下苏州大学苏州大学

第一章测试

Asahigh-speedspaceshipfliespastyou,itfiresastrobelightthatsendsoutapulseoflightinalldirections.Anobserveraboardthespaceshipmeasuresasphericalwavefrontthatspreadsawayfromthespaceshipwiththesamespeedinalldirections.Whatistheshapeofthewavefrontthatyoumeasure?（）

A:sphericalB:ellipsoidal,withthelongestaxisoftheellipsoidalongthedirectionofthespaceship’smotion;C:notenoughinformationisgiventodecide.D:ellipsoidal,withtheshortestaxisoftheellipsoidalongthedirectionofthespaceship’smotion

答案:spherical

Stanley,whoworksfortherailsystem,hascarefullysynchronizedtheclocksatalloftherailstations.AtthemomentthatStanleymeasuresalloftheclocksstrikingnoon,Mavisisonahigh-speedpassengercartravelingfromOgdenvilletowardNorthHaverbrook.AccordingtoMavis,whentheOgdenvilleclockstrikesnoon,whattimeisitinNorthHaverbrook?（）

A:beforenoonB:noonC:notenoughinformationisgiventodecideD:afternoon

答案:afternoon

Samir(whoisstandingontheground)startshisstopwatchattheinstantthatMariafliespasthiminherspaceshipataspeedof0.600c.Atthesameinstant,Mariastartsherstopwatch.AsmeasuredinSamir’sframeofreference,whatisthereadingonMaria’sstopwatchattheinstantthatSamir’sstopwatchreads10.0s?（）

A:notenoughinformationisgiventodecideB:morethan10.0sC:10.0sD:lessthan10.0s

答案:lessthan10.0s

InframeSeventsP1andP2occuratthesamex-,y-andz-coordinates,buteventP1occursbeforeeventP2.InframeS’,eventP1occursfirst。（）

A:对B:错

答案:对

Accordingtorelativisticmechanics,whenyoudoublethespeedofaparticle,themagnitudeofitsmomentumincreasesby（）

A:afactorgreaterthan2B:afactorbetween1and2thatdependsonthemassoftheparticleC:afactorsmallerthan1D:afactorof2

答案:afactorgreaterthan2

第二章测试

Siliconfilmsbecomebetterelectricalconductorswhenilluminatedbyphotonswithenergiesof1.14eVorgreater,aneffectcalledphotoconductivity.Whichofthefollowingwavelengthsofelectromagneticradiationcancausephotoconductivityinsiliconfilms?（）

A:infraredlightwithλ=1200nmB:redlightwithλ=600nmC:ultravioletlightwithλ=300nm

答案:redlightwithλ=600nm;ultravioletlightwithλ=300nm

Intheapparatususedtoproducexrays,similartoRöntgen’s1895apparatus,supposeyouincreasethenumberofelectronsthatareemittedfromthecathodepersecondwhilekeepingthepotentialdifferenceVACthesame.HowwillthisaffecttheintensityIandminimumwavelengthλminoftheemittedxrays?（）

A:IwillincreasebutλminwillbeunchangedB:IwillincreasebutλminwilldecreaseC:noneoftheseD:IwillremainthesamebutλminwilldecreaseE:Iandλminwillbothincrease

答案:Iwillincreasebutλminwillbeunchanged

Ifyouusedvisible-lightphotonsintheCompton-effectexperiment,thephotonswouldundergoawavelengthshiftduetothescattering.（）

A:错B:对

答案:对

Ifyouusedvisible-lightphotonsintheCompton-effectexperiment,itispossibletodetecttheshiftwiththehumaneye。（）

A:错B:对

答案:错

Throughwhichofthefollowinganglesisaphotonofwavelengthλmostlikelytobedeflectedafterpassingthroughaslitofwidtha?Assumethatismuchlessthana.（）

A:θ=λ/aB:θ=2λ/aC:notenoughinformationgiventodecideD:θ=3λ/2aE:θ=3λ/a

答案:θ=3λ/2a

第三章测试

Aprotonhasaslightlysmallermassthananeutron.Comparedtotheneutron,wouldaprotonofthesamewavelengthhave（）?（）

A:morekineticenergyB:lesskineticenergyC:thesamekineticenergy

答案:morekineticenergy

SupposeyourepeatedRutherford’sscatteringexperimentusingathinsheetofsolidhydrogeninplaceofthegoldfoil.(Hydrogenisasolidattemperaturesbelow14.0K.)Thenucleusofahydrogen

atomisasingleproton,withaboutone-fourththemassofanalphaparticle.Comparedto

theoriginalexperimentwithgoldfoil,wouldyouexpectthealphaparticlesinthisexperiment

toundergo（）？（）

A:thesameamountoflarge-anglescatteringB:morelarge-anglescatteringC:lesslarge-anglescattering

答案:lesslarge-anglescattering

ConsiderthepossibletransitionsbetweenenergylevelsinaHe+ion.ForwhichofthesetransitionsinHe+willthewavelengthoftheemittedphotonbenearlythesameasoneofthewavelengthsemittedbyexcitedHatoms？（）

A:n=3ton=2B:n=4ton=3C:noneoftheseD:n=2ton=1E:morethanoneofthese

答案:morethanoneofthese

Anordinaryneonlightfixturelikethoseusedinadvertisingsignsemitsredlightofwavelength632.8nm.Neonatomsarealsousedinahelium–neonlaser(atypeofgaslaser).Thelightemittedbyaneonlightfixtureis（）

A:bothspontaneousandstimulatedemissionB:spontaneousemissionC:stimulatedemission

答案:spontaneousemission

Ablackbodyat2000Kemitsxraysanditalsoemitsradiowaves.（）

A:对B:错

答案:对

第四章测试

Awavepacketgivenbythisequation，，representsastationarystate.（）

A:对B:错

答案:错

Ifaparticleinaboxisinthenthenergylevel,whatistheaveragevalueofitsx-componentofmomentumpx?（）

A:B:C:D:E:zero

答案:zero

Supposethatthewidthofthefinitepotentialwellisreducedbyone-half.HowmustthevalueofU0changesothattherearestilljustthreeboundenergylevelswhoseenergiesarethefractionsofU0?U0must:（）？（）

A:increasebyafactoroffourB:decreasebyafactorofone-fourthC:remainthesameD:increasebyafactoroftwoE:decreasebyafactorofone-half

答案:increasebyafactoroffour

Itispossibleforaparticleundergoingtunnelingtobefoundwithinthebarrierratherthanoneithersideofit.（）

A:错B:对

答案:对

Aquantum-mechanicalsysteminitiallyinitsgroundlevelabsorbsaphotonandendsupinthefirstexcitedstate.Thesystemthenabsorbsasecondphotonandendsupinthesecondexcitedstate.Forwhichofthefollowingsystemsdoesthesecondphotonhavealongerwavelengththanthefirstone?（）

A:aparticleinaboxB:ahydrogenatomC:aharmonicoscillator

答案:ahydrogenatom

第五章测试

Inacertainregionofspacethepotential-energyfunctionforaquantum-mechanicalparticleiszero.Inthisregionthewavefunctionforacertainstationarystatesatisfies,,and.TheparticlehasadefiniteenergyEthatispositive.Whatcanyouconcludeaboutinthisregion?（）

A:itmustbezeroB:itmustbenegativenotenoughinformationgiventodecideC:ItmustbepositiveD:itmustbezero

答案:itmustbezero

RankthefollowingstatesofaparticleinacubicalboxofsideLinorderfromhighesttolowestenergy:

(i)(nX,nY,nZ)=(2,3,2);(ii)(nX,nY,nZ)=(4,1,1);(iii)(nX,nY,nZ)=(2,2,3);(iv)(nX,nY,nZ)=(1,3,3).Theansweris:(iv),(ii),(i)and(iii)(tie).（）

A:对B:错

答案:对

Rankthefollowingstatesofthehydrogenatominorderfromhighesttolowestprobabilityoffindingtheelectroninthevicinityofr=5a(i)n=1,l=0,ml=0;(ii)n=2,l=1,ml=+1;(iii)n=2,l=1,ml=0.（）

A:(ii),(iii),(i)B:(i),(iii),(ii)C:(ii)and(iii)(tie),(i)D:(iii),(ii),(i)

答案:(ii)and(iii)(tie),(i)

Inthissectionweassumedthatthemagneticfieldpointsinthepositivez-component.Theresultswouldbedifferentifthemagneticfieldpointedinthepositivex-direction.（）

A:对B:错

答案:错

Inwhichofthefollowingsituationsisthemagneticmomentofanelectronperfectlyalignedwithamagneticfieldthatpointsinthepositivez-direction?（）

A:ms=+1/2B:bothAandBC:neitherAorBD:ms=-1/2

答案:neitherAorB

第六章测试

Ifelectronsobeyedtheexclusionprinciplebutdidnothavespin,howmanyelectronscouldparticipateinacovalentbond?（）

A:twoB:threeC:morethanthreeD:one

答案:one

Arotatingdiatomicmoleculeemitsaphotonwhenitmakesatransitionfromlevelltol-1levelIfthevalueoflincreases,doesthewavelengthoftheemittedphoton()?（）

A:decreaseB:increaseC:remainunchanged

答案:decrease

IfaisthedistanceinanNaClcrystalfromanNa+iontooneofitsnearest-neighborCl-ions,whatisthe

distancefromanNa+iontooneofitsnext-to-nearest-neighborCl-ions?（）

A:noneoftheseB:C:2aD:

答案:

Onetypeofthermometerworksbymeasuringthetemperature-dependentelectricalresistivityofasample.Whichofthefollowingtypesofmaterialdisplaysthegreatestchangeinresistivityforagiventemperaturechange?（）

A:insulatorB:semiconductorC:resistor

答案:semiconductor

AnidealgasobeystherelationshippV=nRT.Thatis,foragivenvolumeVandanumberofmolesn,asthetemperatureTdecreases,thepressurepdecreasesproportionatelyandtendstozeroasTapproachesabsolutezero.Thisisalsotrueofthefree-electrongasinasolidmetal.（）

A:对B:错

答案:错

第七章测试

Bywhatfactormustthemassnumberofanucleusincreasetodoubleitsvolume?（）

A:2B:C:8D:4

答案:4

Rankthefollowingnucleiinorderfromlargesttosmallestvalueofthebindingenergypernucleon.Theansweris:(ii),(iii),(v),(iv),(i)（）

A:错B:对

答案:错

AnucleuswithatomicnumberZandneutronnumberNundergoestwodecayprocesses.TheresultisanucleuswithatomicnumberZ-3andneutronnumberN-1.Whichdecayprocessesmayhavetakenplace?()?（）

A:TwodecaysB:TwodecaysC:andecayandadecayD:andecayandadecayE:Twodecays

答案:andecayandadecay

Whichsamplecontainsagreaternumberofnuclei:asampleof(half-life6560y)orasampleof(half-life7370y)?（）

A:thesampleB:bothhavethesamenumberofnucleiC:thesample

答案:bothhavethesamenumberofnuclei

Alphaparticleshave20timestherelativebiologicaleffectivenessof200-keVxrays.Whichwouldbebettertousetoradiatetissuedeepinsidethebody?（）

A:abeamof200-keVxraysB:abeamofalphaparticlesC:bothareequallyeffective

答案:abeamof200-keVxrays

第八章测试

Eachofthefollowingparticlescanbeexchangedbetweentwoprotons,twoneutrons,oraneutronandaprotonaspartofthenuclearforce.Ranktheparticlesinorderoftherangeoftheinteractionthattheymediate,fromlargesttosmallestrange.(i)the(pi-plus)mesonofmass(ii)the(rho-plus)mesonofmass(iii)the(eta-zero)mesonofmass(iv)the(omega-ze