gre物理sub题目精选解答

《gre物理sub题目精选解答》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。

1、电磁学1.AFastchargedparticlepassesperpendicularlythroughathinglasssheetofindexofrefraction1.5.TheconeofCerenkovlight,emittedintheglassatangleθ,isincidentontheglass-airinterfaceatthecriticalanglefortotalreflection.Whatisthespeedoftheparticle?answer:2.answer:D3.answer:E一些简单的

2、量子力学题：1.Aparticleofchargeeandmassmistrappedinaone-dimentionalsquarewellofwidth2awithimpenetrablewalls.Thewallsarelocatedatx=−aandx=a.(1)Ifthequantummechanicalstatesarelabledbyn(n=1isthegroundstate),whatistheexpectationvalueofx^2forverylargen?answer:a^2/3(2)Asmallelectri

3、cfieldofstrengthE_0isappliedinthexdirection.Whatisthechangeoftheenergyofthefirstexcitedstateofthisparticleduetothiselectricfield?(Assumethatthetotalpotential,duetothewallsandtheelectricfield,is0atx=0.)answer:02.ThewavefunctionwhereAandbarerealconstants,isanormalizedeige

4、nfunctionoftheSchrödingerequationforaparticleofmassMandenergyEinaonedimensionalpotentialV(x)suchthatV(x)=0atx=0.DeterminetheformofthepotentialV(x)answer:3.answer:E统计：1.answer:B2.answer:BA一些简单的粒子物理题和狭义相对论1.Thehalf-lifeofamesonatrestis2.5×10-8second.Abeamofmesonsisgenerat

5、edatapoint15metersfromadetector.Onlyhalfofthemesonslivetoreachthedetector.Findthespeedofthemesonanswer:2.3.Abeamofparticlesisincidentonathintargetofthicknesst.Ifthecrosssectionpernucleusforascatteringoftheparticlesbythenucleioftheofthetargetisσ,andthenumberofnucleiperun

6、itvolumeisn,whatisthefractionofparticlesscattered?answer:ntσ4.Aprotonbeamisincidentonascatterer0.1centimeterthick.Thescatterercontains10^20targetnucleipercubiccentimeter.Inpassingthroughthescatterer,oneprotonperincidentmillionisscattered.Calculatethescatteringcrosssecti

7、on.answer:10^-25cm^2