浙江大学大学物理甲下-midtese.ppt

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1、AnswertothefinalexaminationⅠ.multiple-choice1.B2.E3.D4.B5.C6.B7.E8.B9.B10.B11.E12.D13.E14.D1.Twoconductingspheresarefarapart.Thesmallerspherecarriesatotalchargeof610-8C.Thelargerspherehasaradiusthatistwicethatofthesmallerandisneutral.Afterthetwosphereareconnectedbyaconductingwir

2、e,thechargesonthesmallerandlargerspheres,respectively,are:A.410-8Cand210-8C.B.210-8Cand410-8C.C.-610-8Cand1210-8C.D.610-8Cand0.E.310-8Cand310-8C.Answer:B2.IftheelectricfieldisinthepositivexdirectionandhasamagnitudegivenbyE=Cx,whereCisaconstant,thentheelectricpotentialisg

3、ivenbyV=A.CB.-CC.CxD.(1/2)Cx2E.-(1/2)Cx2Answer:E3.Whenanexternalelectricfieldisappliedtoaninsulatorwithdielectricconstantκ,themagnitudeoftheelectricfieldproducedintheinsulatorbythepolarizationchargeispropotionaltoA.κ.B.1/κ.C.κ-1.D.1-1/κ.E.1+1/κ.Answer:D4.Eachofthethree25μFcapacit

4、orsshownisinitiallyuncharged.HowmanycoulombsofchargepassthroughtheammeterAaftertheswitchSisclosed?A.0.10B.0.30C.10D.0.033E.Noneofthese.Answer:B5.Abatteryisusedtochargeaparallel-platecapacitors,afterwhichitisdisconnected.Thentheplatesarepulledaparttotwicetheiroriginalseparation.Th

5、isprocesswilldoublethe:A.capacitance.B.surfacechargedensityoneachplate.C.storedenergy.D.electricfieldbetweenthetwoplates.E.chargeoneachplate.Answer:C6.Thecurrentisfromlefttorightintheconductorshown.ThemagneticfieldisoutofthepageandpointSisatahigherpotentialthanpointT.Thechargecar

6、riersare:A.positiveB.negativeC.neutralD.absentE.movingnearthespeedoflightAnswer:B7.Thediagramshowsastraightwirecarryingcurrentiinauniformmagneticfield.Themagneticforceonthewireisindicatedbyanarrowbutthemagneticfieldisnotshown.Ofthefollowingpossibilities,thedirectionofthemagneticf

7、ieldis:A.totherightB.oppositethedirectionofFC.inthedirectionofFD.intothepageE.outofthepageAnswer:E8.Themagnetictorqueexertedonaflatcurrent-carryingloopofwirebyauniformmagneticfieldBis:A.MaximumwhentheplateoftheloopisperpendiculartoBB.MaximumwhentheplateoftheloopisparalleltoBC.Dep

8、endentontheshapeoftheloopforafixedloopar