初三物理实验：测量小灯泡电阻及故障分析.pdfVIP

小红和各自用如图甲所示的电路测量小灯泡的电阻，图乙是他们使用的实验器材，两

人分别测量的小灯泡规格完全相同，均标有“2.5V”字样．

（1）根据图甲，请在答题卡的实物图上用笔画线代替导线，将电路连接完整（导线不交

叉）

（2）小红正确连接电路闭合开关后，发现灯泡不亮，电流表无示数，电压表示数接近电源

电压3V，出现故障的可能是

A．灯泡短路；B．灯泡断路；C．电压表短路；D．电流表断路

（3）排除故障后，他们正确测量了相关数据，并对数据进行了初步处理，如下表和图丙所

示．

次数U/VI/AR/Ω

12.00.229.1

22.50.2410.4

33.00.2611.5

小红的实验数据表格

分析同学的数据图象可知：所测的小灯泡正常发光时的电阻值为Ω．

（4）该实验电路还能测量小灯泡的．

XiaoHongandLiQiangeachusedthecircuitshowninFigureAtomeasuretheresistanceofthesmalllightbulb.

FigureBistheexperimentalequipmenttheyused.Thespecificationsofthesmalllightbulbstheymeasuredwere

exactlythesame,andbothweremarkedwiththeword2.5V.

(1)AccordingtoDiagramA,pleaseusepenlinesinsteadofwiresonthephysicaldiagramoftheanswersheetto

completethecircuitconnection(thewiresdonotcross)

(2)AfterXiaohongcorrectlyconnectedthecircuitandclosedtheswitch,shefoundthatthebulbdidnotlightup,the

ammeterhadnoindication,andthevoltageindicationwasclosetothepowersupplyvoltageof3V.Thecauseofthe

failuremaybe

A.Shortcircuitoflightbulb;B.Opencircuitoflightbulb;C.Shortcircuitofvoltmeter;D.Opencircuitof

ammeter

(3)Aftertroubhooting,theycorrectlymeasuredtherelevantdataandperformedpreliminaryprocessingonthe

data,asshowninthetablebelowandFigureC.

timesU/VI/AR/Ω

12.00.229.1

22.50.2410.4

33.00.2611.5

Xiaohong’sexperimental

datatable

分AnalyzingthedataimageofLiQiang,wecanseethattheresistancevalueofthesmalllightbulbmeasuredbyLi