【答案】《電磁場理論與微波工程》（北京理工大學）章節(jié)作業(yè)慕課答案

有些題目順序不一致，下載后按鍵盤ctrl+F進行搜索Chapter1VectorAnalysisChapter1Quiz11.單選題：Fordescriptionofthedivergenceinthevectorfield,whichofthefollowingstatementsiswrong？

選項：

A、Thedivergenceofvectorisascalar,whichisthefluxofthroughacertainpointperunitvolume.

B、Whenthedivergenceisequalto0,itmeansthatthereisnodivergencesourceatthatpoint.

C、Pointswithdivergencelessthan0emitvectorlines.

D、Avectorfieldwhosedivergenceis0everywhereiscalledadivergence-lessfield.

答案：【Pointswithdivergencelessthan0emitvectorlines.】2.單選題：Whichofthefollowingstatementsiscorrect?

選項：

A、

B、Stokes'theoremis

C、Inthepotentialfield,wehave

D、Thedivergencetheoremis

答案：【Stokes'theoremis】3.單選題：Insphericalcoordinatesystem,thevolumeelementdτcanberepresentedby

選項：

A、

B、

C、

D、

答案：【】4.單選題：Thedirectionalderivativeisequaltotheprojectionofthegradientvectorinthatdirection.

選項：

A、正確

B、錯誤

答案：【正確】5.單選題：InHelmholtz'stheorem,ifthevectorfieldhassinglevalueoneverypointintheinfinitespacewithitsderivativeiscontinuousinboundedregion,andthesourceisdistributedinafiniteregion,thenthevectorfieldisuniquelydeterminedbyitsdivergenceorcurl.

選項：

A、正確

B、錯誤

答案：【錯誤】Chapter2ElectrostaticFieldsChapter2Quiz21.單選題：Thechargewithitsdensityisuniformlydistributedonaconductorspherewithradiusofa,whereisaconstant.Thenthetotalchargeonthesphereis

選項：

A、0

B、

C、

D、

答案：【0】2.多選題：Whataretrueofthefollowingstatements?

選項：

A、Theelectricfieldintensityvectoratapointinspaceisnotperpendiculartotheequipotentialplanepassingthroughthispoint.

B、Theelectricfieldstrengthisdirectedfromthelowpotentialplanetothehighpotentialplane.

C、Thepotentialdifferencebetweentwopointsisindependentofthepositionofthepotentialreferencepoint.

D、Anelectricdipoleisasystemofchargescomposedofapairofpointchargeswiththesamechargequantitybutoppositepolarityseparatedbysomedistance.

答案：【Thepotentialdifferencebetweentwopointsisindependentofthepositionofthepotentialreferencepoint.;Anelectricdipoleisasystemofchargescomposedofapairofpointchargeswiththesamechargequantitybutoppositepolarityseparatedbysomedistance.】3.多選題：Thereisacylinderwithradiusofainheelectricfield,thepotentialsonbothinsideandoutsidethecylinderare:,whichofthefollowingstatementsiscorrect?

選項：

A、Thereisachargeonthesurfaceofthecylinder.

B、Thereisnochargeonthesurfaceofthecylinder.

C、Theelectricfieldintensityisat0ontheinterfaceofr=a.

D、Theelectricfieldoutsidethecylinderisdependentonrand.

答案：【Thereisachargeonthesurfaceofthecylinder.;Theelectricfieldoutsidethecylinderisdependentonrand.】4.多選題：Whichofthefollowingstatementsarewrong?

選項：

A、TheGausslaw’sintegralformis.

B、TheGausslaw’sdifferentialformis.

C、Thelooplaw’sdifferentialformis

D、Thelooplaw’sintegralformis.

答案：【TheGausslaw’sdifferentialformis.;Thelooplaw’sdifferentialformis】5.單選題：TheelectricfieldstrengthofeachpointonanarbitraryGaussiansurfaceintheelectricfieldisdeterminedbythechargesdistributedoutsidetheGaussiansurface.

選項：

A、正確

B、錯誤

答案：【錯誤】6.單選題：Thecurlofelectrostaticfieldinspaceis0everywhere,andthereisnovortexsourceinelectrostaticfield.

選項：

A、正確

B、錯誤

答案：【正確】7.單選題：Thetangentialcomponentoftheelectricfieldstrengthisdiscontinuousontheinterfacebetweentwodielectrics.

選項：

A、正確

B、錯誤

答案：【錯誤】Chapter3ElectrostaticFieldsChapter3Quiz31.單選題：Steadycurrentfieldinconductivemediumsatisfies().

選項：

A、

B、

C、

D、

答案：【】2.多選題：Theboundaryconditionofsteadycurrentfieldinconductivemediumis().

選項：

A、

B、

C、

D、

答案：【;】3.多選題：Inthefollowingexpressions,whicharecorrect?

選項：

A、Thedifferentialformofsteadycurrentcontinuityequationis.

B、ThedifferentialformofOhm'slawis.

C、ThepotentialforsteadycurrentfieldinahomogenousconductingmediumsatisfiesLaplace'sequation.

D、ThedifferentialformofJoule'slawis.

答案：【ThedifferentialformofOhm'slawis.;ThepotentialforsteadycurrentfieldinahomogenousconductingmediumsatisfiesLaplace'sequation.;ThedifferentialformofJoule'slawis.】4.單選題：Thenormalcomponentofthecurrentdensityisdiscontinuousontheinterfacebetweendifferentdielectrics.

選項：

A、正確

B、錯誤

答案：【錯誤】5.單選題：Thecurrentwhichisinvariantwithtimeiscalledsteadycurrent,andthecorrespondingelectricfieldissteadycurrentfield.

選項：

A、正確

B、錯誤

答案：【正確】Chapter4MagnetostaticFieldsChapter4Quiz41.單選題：In(),magnetizationphenomenonoccursundertheactionofexternal().

選項：

A、Magneticmedium,electricfield

B、Magneticmedium,magneticfield

C、Dielectric,magneticfield

D、Dielectric,electricfield

答案：【Magneticmedium,magneticfield】2.單選題：Inthemagneticmedium,istheintegralformofthe().

選項：

A、Lawofelectromagneticinduction

B、GaussTheorem

C、Ampere’slooptheorem

D、Currentcontinuityequation

答案：【Ampere’slooptheorem】3.多選題：Whichofthefollowingdescriptionarecorrect?

選項：

A、Whenfreecurrentsexistontheinterface,thetangentialcomponentofthemagneticfieldstrengthisdiscontinuousattheinterface.

B、Theclosedmagneticlinesatisfiestheleft-handedscrewrelationwiththecurrentintersectsit.

C、Theconstitutiverelationofamagnetostaticfieldinthemagneticmediumis.

D、Theintegralformofthemagneticfluxcontinuityequationis

答案：【W(wǎng)henfreecurrentsexistontheinterface,thetangentialcomponentofthemagneticfieldstrengthisdiscontinuousattheinterface.;Theintegralformofthemagneticfluxcontinuityequationis】4.單選題：Thetangentdirectionofanarbitrarypointofthemagneticinductionlineisthedirectionofthemagneticfieldstrength

選項：

A、正確

B、錯誤

答案：【錯誤】5.單選題：Theelectricfieldmustbegeneratedbytheelectriccharge,andthemagneticfieldmustbegeneratedbytheelectriccurrent.

選項：

A、正確

B、錯誤

答案：【錯誤】Chapter5ElectromagneticInductionChapter5Quiz51.單選題：Asingle-turnloopwithanareaof0.1m2isplacedinthemagneticfieldwiththefrequencyof10MHzintheair.Iftheelectromotiveforceof1Vistobeinducedontheloop,theminimummagneticfieldstrengthHrequiredis()A/m?

選項：

A、0.1

B、0.111

C、0.125

D、0.126

答案：【0.126】2.單選題：Alongsolenoidwithradiusofisaistightlywindedbycoilofnturnsperunitlength.Ifthepermeabilityoftheironcoreisμ,theself-inductanceperunitlengthis().

選項：

A、

B、

C、

D、

答案：【】3.單選題：Alongsolenoidwithradiusofisaistightlywindedbycoilofnturnsperunitlength.IfthereisacurrentIinthecoil,findthemagneticfieldenergystoredperunitlength.(Supposethepermeabilityoftheironcoreisμ)

選項：

A、

B、

C、

D、

答案：【】4.單選題：Themagneticfieldvarieswithtime,buttheshapeandpositionoftheloopisstationary.Theelectromotiveforceonlygeneratedbythemagneticfluxchangeduetothetimevaryingmagneticfieldistheinducedelectromotiveforce.

選項：

A、正確

B、錯誤

答案：【正確】5.單選題：Lenz'slawstatesthatthemagneticfluxgeneratedbytheinducedcurrentalwaystriestocompensateforthechangeintheoriginalmagneticflux.

選項：

A、正確

B、錯誤

答案：【正確】Chapter6TimeVaryingElectromagneticFieldChapter6Quiz61.單選題：TheMaxwell'sequationsdescribeswhichofthefollowingrelation().

選項：

A、electrostaticandstaticmagneticfields

B、theinteractionofchangingelectricandmagneticfields

C、electrostaticandchangingmagneticfields

D、changingelectricandstaticmagneticfields

答案：【theinteractionofchangingelectricandmagneticfields】2.單選題：ThegeneralizedAmpere'sCircuitLawincludesthedisplacementcurrentconsidering().

選項：

A、thechangesinelectricfieldstrength

B、thechangesinmagneticfieldstrength

C、thechangesincurrentstrength

D、theequations’consistency

答案：【theequations’consistency】3.單選題：Inasinusoidalelectromagneticfield,electricandmagneticfieldshavewhichofthefollowingpropertiesregardingtheiramplitude().

選項：

A、theelectricfieldhasconstantamplitude.

B、themagneticfieldhasconstantamplitude.

C、theamplitudesoftheelectricandmagneticfieldsareproportionaltoeachother

D、theamplitudesoftheelectricandmagneticfieldsareindependentofeachother

答案：【theamplitudesoftheelectricandmagneticfieldsareproportionaltoeachother】4.單選題：Boundaryconditionsfortime-varyingelectromagneticfieldsapplyonlytothesurfaceofaconductor.

選項：

A、正確

B、錯誤

答案：【錯誤】5.單選題：Boundaryconditionsfortime-varyingelectromagneticfieldscanbeusedtodescribethereflectionofelectromagneticwaves.

選項：

A、正確

B、錯誤

答案：【正確】Chapter7PlaneWavesChapter7Quiz71.單選題：Thepolarizationdirectionofalinearlypolarizedwaveisdeterminedby().

選項：

A、theelectricfieldvectormovingdirection

B、themagneticfieldvectormovingdirection

C、thewavepropagationdirection

D、theanglebetweentheelectricandmagneticfieldvectors

答案：【theelectricfieldvectormovingdirection】2.單選題：Thewaveimpedanceofauniformplanewaveinanidealmediumisdependenton().

選項：

A、thefrequencyofthewave

B、theamplitudeofthewave

C、thepermittivityandpermeabilityofthemedium

D、thephasevelocityofthewave

答案：【thepermittivityandpermeabilityofthemedium】3.單選題：Whichisthewaveequationforauniformplanewaveinanidealmedium?

選項：

A、

B、

C、

D、

答案：【】4.單選題：Inanidealmedium,thewavelengthofauniformplanewavedependsonlyonthefrequencyofthewave.

選項：

A、正確

B、錯誤

答案：【錯誤】5.單選題：Whentheuniformplanewavepropagatesinanidealmedium,itswavelengthvarieswithpropagationdistance.

選項：

A、正確

B、錯誤

答案：【錯誤】Chapter8GuidedWavesChapter8Quiz81.單選題：Fortheelectromagneticwaveatafixed-frequency,thegroupvelocityofthisguidedwaveinaPECwaveguideisusually():

選項：

A、higherthanthephasevelocity

B、lowerthanthephasevelocity

C、equaltothephasevelocity

D、itcannotbedetermined

答案：【lowerthanthephasevelocity】2.單選題：Whichisthefundamentalmodeofarectangularwaveguide?

選項：

A、

B、

C、

D、

答案：【】3.單選題：InaPECwaveguide,whichofthefollowingfactorsaffectsthepropagationcharacteristicsofaguidedelectromagneticwave?

選項：

A、thewavelengthoftheelectromagneticwave

B、thefrequencyoftheelectromagneticwave

C、theshapeandsizeofthewaveguide’scross-section

D、theincidentangleoftheelectromagneticwave

答案：【theshapeandsizeofthewaveguide’scross-section】4.單選題：Thecutofffrequencyofallmodesinarectangularwaveguideisrelatedtotheheightandwidthofthewaveguide.

選項：

A、正確

B、錯誤

答案：【正確】5.單選題：Inarectangularwaveguide,thehigherordermodesexceptforthefundamentalmodecanbetransmittedinasinglemode.

選項：

A、正確

B、錯誤

答案：【錯誤】Chapter9RadiationofElectromagneticWaveChapter9Quiz91.單選題：Theradiationfieldofanelectricdipoleinthefar-fieldregionusuallybehaves()

選項：

A、inthesamedirectionasthedipoleaxis

B、perpendiculartothedipoleaxis

C、independentofthedipoleaxis

D、withanangleof45degreestothedipoleaxis

答案：【perpendiculartothedipoleaxis】2.單選題：TheHertziandipoleiscenteredattheorigin,itsfar-fieldexpressionhaswhichofthefollowingrelationwiththedistancefromobservationpointtooriginr?

選項：

A、thefieldisproportionalto1/r

B、thefieldisproportionalto1/r2

C、thefieldisproportionalto1/r3

D、hasnothingtodowithr

答案：【thefieldisproportionalto1/r】3.單選題：WhichofthefollowingisNOTantennaspecification?

選項：

A、radiationpattern

B、gain

C、efficiency

D、resistance

答案：【resistance】4.單選題：Thedualityofelectricityandmagnetismimpliestheelectricandmagneticfieldsbehavethesameinallcases.

選項：

A、正確

B、錯誤

答案：【錯誤】5.單選題：Theradiationpowerofanelectricdipoleisproportionaltoitsfrequency.

選項：

A、正確

B、錯誤

答案：【錯誤】Chapter10TransmissionLineTheoryChapter10Quiz101.單選題：Thetransmissionlinewithlengthof1mcarryinga900MHzsignalis().

選項：

A、Longlineandlumpedelementcircuit

B、Longlineanddistributedelementcircuit

C、Shortlineandlumpedelementcircuits

D、Shortlineanddistributedelementcircuits

答案：【Longlineanddistributedelementcircuit】2.多選題：Whichofthefollowingstatementarecorrect?

選項：

A、Electromagneticenergyistransmittedintwoways.Oneiscarriedbythecurrentintheconductorofthetransmissionline.Theotherispropagatedbythemediumaroundthetransmissionlineconductor.

B、Atransmissionlinewithl/λ>0.1isgenerallyconsideredasalongline

C、Therearethreeoperatingstatesonlosslesstransmissionlines:travelingwave,standingwaveandtravelingstandingwave

D、Transmissionpowerisequaltoreflectedpowerminusincidentpower

答案：【Electromagneticenergyistransmittedintwoways.Oneiscarriedbythecurrentintheconductorofthetransmissionline.Theotherispropagatedbythemediumaroundthetransmissionlineconductor.;Atransmissionlinewithl/λ>0.1isgenerallyconsideredasalongline;Therearethreeoperatingstatesonlosslesstransmissionlines:travelingwave,standingwaveandtravelingstandingwave】3.多選題：Whenanalyzingthetransmissionlinebydistributedelementequivalentcircuit,whichofthefollowingstatementarecorrect?

選項：

A、ThedistributedresistanceRisgeneratedduetothenon-idealoftheconductorsconstitutingthetransmissionline

B、ThedistributedconductanceGisgeneratedduetothenon-idealmediumbetweenthetwoconductorsofthetransmissionline

C、ThedistributedinductanceLisproducedbytheself-inductanceofthetransmissionline

D、ThedistributedcapacitanceCisproducedbythevoltagedropbetweenthetwowires

答案：【ThedistributedresistanceRisgeneratedduetothenon-idealoftheconductorsconstitutingthetransmissionline;ThedistributedconductanceGisgeneratedduetothenon-idealmediumbetweenthetwoconductorsofthetransmissionline;ThedistributedinductanceLisproducedbytheself-inductanceofthetransmissionline;ThedistributedcapacitanceCisproducedbythevoltagedropbetweenthetwowires】4.單選題：Forapurelyreactiveloadwithimpedanceof,thereflectioncoefficientmagnitudeisalwaysunity.AssumethatthecharacteristicimpedanceZ0isreal.

選項：

A、正確

B、錯誤

答案：【正確】5.單選題：Thekeydifferencebetweencircuittheoryandtransmissionlinetheoryistheelectricalsize.

選項：

A、正確

B、錯誤

答案：【正確】Chapter11MicrowaveNetworkAnalysisChapter11Quiz111.單選題：Amongbelowstatementsregardingtheimpedance,whichisINCORRECT?

選項：

A、ηrepresentstheintrinsicimpedanceofamedium.Thisimpedanceisonlydependentonthematerialparametersofthemedium,andisequaltothewaveimpedanceoftheplanewave.

B、Zωstandsforthewaveimpedance.Theimpedanceisacharacteristicofaparticularwavetype.TEM,TMandTEwaveshavedifferentwaveimpedancesdependingonthetypeoftransmissionlineandwaveguide,materialproperties,andoperatingfrequency.

C、Z0representsthecharacteristicimpedance.Thecharacteristicimpedanceistheratioofthetravelingwavevoltagetothecurrentonthetransmissionline.TherearenouniquelydefinedvoltagesandcurrentsforTEM,TE,andTMwaves.

D、Similarasthepropertiesofplaneelectromagneticwave,theimpedanceoftransmissionlineisdependentonthepropagationdirection.Inthisway,impedancecanbeconsideredasthelinkbetweenfieldtheoryandtransmissionline/circuittheory.

答案：【Z0representsthecharacteristicimpedance.Thecharacteristicimpedanceistheratioofthetravelingwavevoltagetothecurrentonthetransmissionline.TherearenouniquelydefinedvoltagesandcurrentsforTEM,TE,andTMwaves.】2.多選題：Acomplexmicrowavenetworkconsistsofmanysimplemicrowavenetworkswhichareclassifiedindifferentways.Whichofthefollowingstatementarecorrect?

選項：

A、Accordingtothenumberoftransmissionlineportsconnectedtoit,themicrowavenetworkcanbedividedintooneport,twoports,andmulti-portnetwork.

B、Accordingtothepropertiesofthecircuitcomponents,themicrowavenetworkcanbedividedintoactiveandpassivenetworks,linearandnonlinearnetworks,andreversibleandnon-reversiblemicrowavenetworks.

C、Thepowerdividerandferritey-shapedcirculatorbelongtothefour-portnetwork.Andthehybridconnectors,directionalcouplers,anddirectionalfiltersbelongtothethree-portnetwork.

D、Examplesoftwo-portnetworkincludemicrowavefilters,modeconverters(usedtotransformoneelectromagneticwavemodeinthewaveguidetoanother),polarizationconverters(usedtochangethepolarizationpropertiesofelectromagneticwavesinthewaveguide),phaseshifters,ferritesandisolators.

答案：【Accordingtothenumberoftransmissionlineportsconnectedtoit,themicrowavenetworkcanbedividedintooneport,twoports,andmulti-portnetwork.;Accordingtothepropertiesofthecircuitcomponents,themicrowavenetworkcanbedividedintoactiveandpassivenetworks,linearandnonlinearnetworks,andreversibleandnon-reversiblemicrowavenetworks.;Examplesoftwo-portnetworkincludemicrowavefilters,modeconverters(usedtotransformoneelectromagneticwavemodeinthewaveguidetoanother),polarizationconverters(usedtochangethepolarizationpropertiesofelectromagneticwavesinthewaveguide),phaseshifters,ferritesandisolators.】3.多選題：Whichofthefollowingstatementarecorrect？

選項：

A、Therearemultiplewaystodefinetheequivalentvoltage,currentandimpedanceofthewaveguide,asthesequantitiesarenotuniquefornon-TEMlines

B、Whenthevoltageandcurrentaredefinedforaspecificwaveguidemode,thevoltagedefinedisproportionaltothetransverseelectricfield,andthecurrentdefinedisproportionaltothetransversemagneticfield.

C、Thesameasthevoltageandcurrentinthecircuittheory,theproductofthoseequivalentvoltageandcurrentinthetransmissionlinetheoryshouldbedeterminedasthepowerflow.

D、Thevoltagetocurrentratioofasingletravelingwaveshouldbeequaltothecharacteristicimpedanceofthetransmissionline.Theimpedanceisarbitraryinchoice,butitisusuallychosentobeequaltothewaveimpedanceofthetransmissionlineornormalizedto1.

答案：【Therearemultiplewaystodefinetheequivalentvoltage,currentandimpedanceofthewaveguide,asthesequantitiesarenotuniquefornon-TEMlines;Whenthevoltageandcurrentaredefinedforaspecificwaveguidemode,thevoltagedefinedisproportionaltothetransverseelectricfield,andthecurrentdefinedisproportionaltothetransversemagneticfield.;Thesameasthevoltageandcurrentinthecircuittheory,theproductofthoseequivalentvoltageandcurrentinthetransmissionlinetheoryshouldbedeterminedasthepowerflow.;Thevoltagetocurrentratioofasingletravelingwaveshouldbeequaltothecharacteristicimpedanceofthetransmissionline.Theimpedanceisarbitraryinchoice,butitisusuallychosentobeequaltothewaveimpedanceofthetransmissionlineornormalizedto1.】4.單選題：Themicrowavenetworkreferstoanareaofarbitraryshapeandstructurewithanumberofoutputandinputportswhichisafunctionalmicrowavecircuitorsystemcomposedofmicrowavecomponentsconnectedbywaveguidesortransmissionlines.

選項：

A、正確

B、錯誤

答案：【正確】5.單選題：Microwaveelementslikedirectionalcouplersandphaseshiftersareequivalenttolossymicrowavenetworks,whilemicrowaveelementslikematchingloadsandattenuatorsareequivalenttolossymicrowavenetworks.

選項：

A、正確

B、錯誤

答案：【錯誤】Chapter12ImpedanceMatchingandTuningChapter12Quiz121.單選題：WhichofthefollowingmethodsCANNOTbeusedforimpedancematching?

選項：

A、λ/4impedanceconverter

B、Singlestub

C、lumpedelements

D、filter

答案：【filter】2.單選題：Inordertoachievemaximumoutputpowerdeliveredfromthesignalsource,itisrequiredthattheinternalimpedanceofthesignalsourceandtheinputimpedanceatthestartingpointofthetransmissionlinehaswhichofthefollowingrelation.().

選項：

A、theyarewiththeoppositepolarity

B、theyareconjugatecomplexnumbers

C、thelatteristheabsolutevalueoftheformer

D、theyarereciprocal

答案：【theyareconjugatecomplexnumbers】3.單選題：thepurposeofmakingtheloadresistanceequaltothecharacteristicresistanceofthetransmissionlineis()?

選項：

A、sothattheloadabsorbsalltheincidentpowerwithoutanyreflectingwaves

B、sothatloadwillreflectallthewaves

C、sothattheloadcanreflecttheelectromagneticwaves

D、sothattheloaddoesnothavetheheatloss

答案：【sothattheloadabsorbsalltheincidentpowerwithoutanyreflectingwaves】4.單選題：Thematchingnetworkisideallylossless.Soitisusuallydesignedwiththeimpedanceseenlookingintothematchingnetworkis1/Z0.

選項：

A、正確

B、錯誤

答案：【正確】5.單選題：Whenadoptingaλ/4impedancetransformerinmatching,weshouldconnectittothemaintransmissionlineatthelocationwheretheinputimpedanceispurelyresistiveseenlookingtowardstheload.

選項：

A、正確

B、錯誤

答案：【正確】Chapter13MicrowaveComponentsChapter13Quiz131.單選題：WhichoffollowingisNOTtraditionalmicrowavecomponents?

選項：

A、E-andH-planewaveguideT-junction

B、Waveplate

C、MagicT

D、Thecouplersusingcoaxialprobes

答案：【W(wǎng)aveplate】2.多選題：Thecharacteristicso