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时间:2021-04-15
《GRE物理Sub题目精选解答.doc》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、电磁学1.AFastchargedparticle passesperpendicularlythrough a thinglasssheetofindexofrefraction 1。5.TheconeofCerenkovlight, emittedintheglassatangle θ, isincidentontheglass-airinterfaceatthe criticalanglefortotalreflection。 Whatisthespeedoftheparticle?answer:2.answer: D3.answer:E一些简单的量子力学题
2、:1。Aparticleof chargeeand mass mistrappedinaone—dimentionalsquarewellofwidth2a withimpenetrablewalls.Thewallsarelocatedat x=−aandx=a.(1)If thequantum mechanical statesarelabledbyn ( n=1isthegroundstate), what isthe expectationvalueofx^2for verylarge n ?answer: a^2/3(2)Asmallelectric f
3、ieldofstrengthE_0isappliedin thex direction.Whatisthechange oftheenergy ofthefirstexcitedstateofthisparticleduetothiselectricfield? (Assume that the totalpotential,duetothewallsand theelectricfield,is0 atx=0。)answer: 0 2.The wavefunctionwhere Aandbarereal constants,is anormalizedeigen
4、function ofthe Schrödinger equationforaparticleofmassMandenergyEinaonedimensionalpotential V(x) suchthatV(x)=0atx=0.Determinetheform ofthepotentialV(x)answer:3.answer:E统计:1.answer:B2。answer: B A一些简单的粒子物理题和狭义相对论1.Thehalf-lifeofa meson atrestis2.5×10-8 second。A beamof mesonsisgenerate
5、datapoint15 metersfroma detector。Onlyhalfofthemesonslive toreachthedetector。 Findthespeedofthe mesonanswer:2.3。Abeamofparticlesisincidenton a thintargetof thicknesst。If the crosssectionpernucleusfor ascatteringoftheparticlesbythenuclei ofthe ofthetargetisσ, andthe numberof nucleiperun
6、itvolumeis n,whatisthe fractionof particlesscattered?answer:ntσ4.Aprotonbeamis incidentonascatterer0。1centimeterthick.The scatterercontains 10^20targetnucleipercubiccentimeter.Inpassingthroughthescatterer, oneprotonperincidentmillionisscattered。Calculate thescatteringcrosssection.answ
7、er:10^—25cm^2
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