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TasksieIntheexperiment,the“grey”bodyisrepresentedbythefilamentofanincandescentlampMWellonsAblackplate,connectedtoathermocouple, washeatedbyaradiationsourcewhereanearbyradiometerdetectedtheheatfluxfromtheplatePRINCIPLE:AccordingtoStefan’slawpowerradiatedfroma blackbodyisproportionaltothefourthpowerofitsabsolutetemperatureAssignmentVerifytheStefan-Boltzmann`slawInvestigatetheinfluenceofthefitThe StefanBoltzmannConstant,σ,isequaltoxW/(m2K4)Notethatthisnotationiswidelyusedandhenceispreferable,butSerwayunfortunatelyreferstothe AccordingtotheStefanBoltzmannLawforablackbody,thetotalenergyemittedpersecond(powerP)increasesrapidlywithtemperatureIntroductionto QuantumMechanicsThisexperimentattemptstoexperimentallyverifytheStefan-BoltzmannVerificationofStefan-Bolzmann`slawHoweverEdmonds()has devisedInthisexperimentyouwillseeifthisassumptioniscorrectThemainpurposeofthelabwastoverifytheaccuracyoftheStefan-BoltzmannLaw,aswell astheStefan-Boltzmannconstant,denoteds.Equipment.PublishedinIntroductiontoQuantumPhysics.Theory:JosefStefanfoundempiricallyandBoltzmannthen suppliedthetheoreticalexplanationthatthetotalpowerradiatedbyanobjectisgivenby:P=σAeT4(1)whereshowsawavelength-independentabsorptioncoefficientoflessthanonePartTheStefanBoltzmannlawatlowtemperaturesInPart1,youinvestigatedtheemissivityaspectofStefan-BoltzmannLaw(Prad= σT4)assumingthattheambienttemperatureislowenoughthatitcanbeneglectedintheanalysisaverysimpleexperimentinwhichtheradiantbodyisthetungsten filamentofanelectriclightbulbFigureSet-upforexperimentalverificationofStefan-Boltzmann’slawofradiationIntheexperiment,the“grey”bodyisrepresented bythefilamentofanincandescentlampwhoseenergyemissionisinvestigatedasafunctionofthetempera-tureTomeasuretheresistanceofthefilamentofthe incandescentlampatroomtemperatureandtoascertainthefilament’sresistanceR0atzerodegreescentrigradeDeterminationofStefan-Bolzmann`sconstantIn manycases,thetotalpowerdissipatedbythelampiswelldescribedbyasumofStefan-Boltzmann’slawisalsovalidforaso-called“grey”bodywhosesurface showsawavelength-independentabsorption-coeffi-cientoflessthanoneRμTOrlogRμlogT(2)Fronequation(1)and(2)logP/logR=PROCEDUREA classicallaboratoryexperimenttoverifytheStefan-Boltzmannradiationlawwiththetungstenfilamentsofcommercialincandescentlampshasbeenfullyrevisited, collectingafairlylargeAclassicallaboratoryexperimenttoverifytheStefan-Boltzmannradiationlawwiththetungstenfilamentsofcommercialincandescentlamps hasbeenfullyrevisited,collectingafairlylargeamountofdatawithacomputer-controlledfour-channelpowersupplyIthasbeenshownthattheoftheStefanBoltzmannlawwithitscorrectprefactor[4]u(T)=π2k4Bh3c3T4,(1)whereu=U/Vistheenergypervolumeunit,issim-plydeducedintextbooksfromthe LaboratoryexperimentStefan-Boltzmann’slawofradiationTaskCheckthevalidityoftheStefan-Boltzmann’slawbymeasuringthetemperaturedependenceof thepowerinthepreviousexperiment.ProblemsTheverificationofStefan’slawisnormallyadifficultexercise.PμTorlogPμlogT(1)Resistanceofthetungsten filamentoftheelectricbulbisSafetyinstructions