選修3-1物理《電源和電流》課堂同步練習(xí)(含解析)

Chapter2Section1:PowerandCurrentMultipleChoiceQuestions:1.Whichofthefollowingstatementsaboutelectriccurrentiscorrect?A.Themoreelectricchargepassingthroughthecross-sectionofawire,thelargertheelectriccurrent.B.Thefasterthespeedofelectronmovement,thelargertheelectriccurrent.C.Themoreelectricchargepassingthroughthecross-sectionofaconductorinaunitoftime,thelargertheelectriccurrentintheconductor.D.Electriccurrentisavectorquantitybecauseithasdirection.2.Iftheelectriccurrentinawireis7.5×10^-3A,whatisthetimerequiredfor15Cofelectricchargetopassthroughacross-sectionofthewire?A.2.0×10^4sB.2.0×10^6sC.2.0×10^5sD.2.0×10^3s3.Whichofthefollowingstatementsaboutthedirectionofelectriccurrentiscorrect?A.Inanexternalcircuitpoweredbyavoltagesource,electriccurrentflowsfromthehighpotentialendtothelowpotentialend.B.Insideavoltagesource,electriccurrentflowsfromthehighpotentialendtothelowpotentialend.C.Thedirectionoftheequivalentcurrentgeneratedbyelectronmovementisthesameasthedirectionofelectronmovement.D.Whenacapacitorisbeingcharged,electriccurrentflowsoutofthenegativeelectrodeandintothepositiveelectrode.4.Inanelectrolyticcell,if5×10^18divalentpositiveionsand1.0×10^19univalentnegativeionspassthroughacertaincross-sectionin1second,whatistheelectriccurrentpassingthroughthiscross-section?A.0AB.0.8AC.1.6AD.3.2A5.ThefollowingstatementsaboutMP4playersarecorrect,except:A.WithMP4players,peoplecanwatchmoviesduringajourneyandmakethetripmoreenjoyable.B.TherechargeablebatteryinmostMP4playersisalithium-ionbattery.C.DuringthechargingprocessofanMP4playerbattery,otherformsofenergyareconvertedintoelectricalenergy.D.DuringthechargingprocessofanMP4playerbattery,electricalenergyisconvertedintootherformsofenergy.Assumingthatthechargingcurrentofalithium-ionbatteryis500mA,whichofthefollowingstatementsiscorrect?A.Theamountofelectricchargepassingthroughacross-sectionofthebatteryin1secondis500C.B.Theamountofelectricchargepassingthroughacross-sectionofthebatteryin1secondis0.5C.6.ArubberringwithauniformpositivechargeQandradiusRisrotatingaroundanaxisperpendiculartotheplaneoftheringandpassingthroughthecenteroftheringataconstantangularvelocityω.Whatistheequivalentelectriccurrentgeneratedbythering?A.IfQisdoubledwhileωremainsconstant,theelectriccurrentwillalsodouble.B.IfωisdoubledwhileQremainsconstant,theelectriccurrentwillalsodouble.C.IfωandQremainconstant,stretchingtherubberringtoincreaseitsradiuswillincreasetheelectriccurrent.D.IfωandQremainconstant,stretchingtherubberringtoincreaseitsradiuswilldecreasetheelectriccurrent.Non-multiplechoicequestions:7.Themotionofanelectronaroundthenucleusofanatomcanbeequivalenttothatofacircularelectriccurrent.IfanelectroninthegroundstateofahydrogenatommovesinacircularpathwitharadiusofR,amassofm,andachargeofe,whatisthemagnitudeofthiscircularelectriccurrent?(Assumetheelectrostaticconstantkisknown.)8.Iftheelectriccurrentinawireis10^-8Aandthecross-sectionalareaof