資源描述：
《M33_KNIG7655_03_ITG_CH33》由會員上傳分享，免費在線閱讀，更多相關(guān)內(nèi)容在學(xué)術(shù)論文-天天文庫。
1、CHAPTER33ElectromagneticInductionRecommendedclassdays:3BackgroundInformationFaraday’slawandelectromagneticinductioncompletethebasicdevelopmentofelectricityandmagnetism.Therearetwoimportantideas.First,thediscoveryofinducedelectricfieldsthatareindependentofchargesisimpor
2、tantevidencefortherealityoffields.Theelectricfieldwasintroducedinaratheradhocfashion,anditisimportantforstudentstounderstandwhy,inretrospect,weattachsuchimportancetothefieldconcept.Second,electromagneticinductionallowsaqualitativedescriptionofelectromagneticwaves.While
3、thedetailsrequireMaxwell’sequations,studentscanatleastbeawarethatanelectromagneticwaveisaself-sustainingfieldconfigurationinwhicheachfieldisinducedbythechangingoftheotherfield.Thereislittleresearchthatbearsdirectlyonstudents’understandingofFaraday’slaworLenz’slaw.Asmos
4、tinstructorsareaware,manystudentsthinkthattheinducedfieldopposestheappliedfielditselfratherthanopposesthechangeintheappliedfield.Itislikelythatthiserrorarisessimplyfromlackofsufficientopportunitiesforqualitativereasoning,withappropriatefeedback,ratherthanfromanyfundame
5、ntalmisconceptionsaboutthenatureofelectromagneticinduction.TotheextentthatFaraday’slawdependsontheconceptofflux,thelimitedresearchonGauss’slawattheUniversityofWashingtonmayberelevant.Theyfoundthatlessthan15%ofstudentscoulduseGauss’slawtoreasonaboutelectricfields.Althou
6、ghthespecificdifficultieshavenotbeenfullyexplored,atleastoneseemstobedifficultywiththeideaofflux.Faraday’slawiseasierinthesensethatwe’llconsiderfluxonlythroughplanarsurfaces,ratherthanthroughthesphericalandcylindricalsurfacesofGauss’slaw.Nonetheless,instructorsshouldan
7、ticipateneedinganumberofdemonstrationsandexercisestoconveytheideaofflux,especiallyifChapter27wasomitted.33-1StudentLearningObjectives?Toobservetheexperimentalevidenceforelectromagneticinduction.?TounderstandanduseLenz’slawforinducedcurrents.?TolearnofFaraday’slawasanew
8、lawofnature.?Tounderstandbasicapplicationsofelectromagneticinductiontotechnology.?Togainaqualitativeunderstandingofel
