浙江大学大学物理甲下-exercise--4.ppt

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1、ExerciseLessonModernPhysicsStefan-Boltzmannlaw—Thetotalradiatedpowerperarea:Wiendisplacementlaw:(1).ThermalRadiation(2).ThePhotoelectricEffectStoppingpotentialandCutofffrequency1.Thenatureoflight(3).TheComptonEffectExample1:TheradiationoftheSun,λm=490nm,canberegardedastheradiationofablackb

2、ody.IftheEarthcanberegardedasablackbodyalso,estimatethetemperatureoftheEarth’ssurface.（RS=6.96×108m,RE=6.37×106m,distancebetweentheSunandtheEarthd=1.496×1011m.)Solution:ThepoweremittingfromperunitsurfaceoftheSunisThepowerperunitareaabsorbedintheEarthsurfacefromtheSunradiationisTotalpowerra

3、diatingfromtheSunisdisthedistancebetweentheSunandtheEarth.ThetotalpowerabsorbedfromtheSunisThepowerofradiationperareaoftheEarth’surfaceisIE.Example2:Aphotonofx-raywiththewavelengthλ=0.02nmiscollidedwithanelectronatrest.Thescatteringradiationisobservedfromthedirectionthatisangular90°withthe

4、incidentdirection.Find:(1)thewavelengthofthescatteringx-ray;(2)theenergyoftherecoilingelectron;(3)themomentumoftherecoilingelectron.xyxyPeh/0h/Solution:2.Thewavesofmatter(1).uncertaintyrelationshipExample3:TheDavisson-Germerexperiment(p1036)Bragg’slawθφadα(unitcelldimensiona=0.215nm,spa

5、cingofadjacentplanesd=0.091nm)E46-17:(p1052)Therearenodiffractionorderotherthanthefirst.(2).WavefunctionΨprobabilitydensitySchrödinger’sEquationForafreeparticleExample4:Aparticleismovinginaonedimension,rectangularinfinitedeeppotentialwell.ItswavefunctionisIftheparticleisinthestateofn=1,fin

6、dtheprobabilitythattheparticlediscoveredinx=0～a/4.Solution:(1)TheGroundStateoftheHydrogenAtomThesolutionofthegroundstate3.HydrogenatomRadialprobabilitydensityP(r)(2).Fourquantumnumbersn=1,2,3,…l=0,1,2,…,n-1.ml=0,±1,…,±(l-1),±l(3).SpectrumofhydrogenatomforBalmerseries,k=2.(4)Bohr’smodelofth

7、ehydrogenatomTheorbiteofHydrogenatomTheenergyofelectronExample5:Accordingtothequantumtheory,whatistheangularmomentumofaelectronintheHydrogenatom?Iftheprinciplequantumnumbern=3,whatcanyousayabouttheangularmomentumofaelectronintheHydrogenatom?Solution:n=3,l=0,1,