问题 探究题

在探究“通过导体的电流跟导体电阻的关系”时,小明设计了如图甲所示的电路,

(1)根据图甲将电路图的实物对应连接起来

(2)连接完后,小明稍作思考之后,就将电路改进为如图乙所示的电路.她这样改进有何好处?_________.(选填“A或B”)

A.方便改变电阻,操作简便;

B.保护电路.在实验过程中,他保持电源电压不变,通过调节电阻箱先后6次改变A、B间的电阻值,测得相应的电流值如下表所示.

(3)小明分析表中的数据,发现总结不出电流跟电阻成反比,你认为其原因是_________

(4)小明认真思考后发现了自己在实验过程中的错误,并采取了正确的实验操作.你认为小明每次改变电阻后应该采取的正确操作是: _________

(5)正确操作实验后,小明将得到的实验数据记录在下表中,请分析下表中的数据,你能得出什么结论? _________

答案

解:

(1)从正极开始依次连接滑动变阻器、定值电阻、电流表、开关、回到电源负极;最后把电压表并联在电阻两端;如图:

(2)A;

(3)没有控制电阻两端的电压相等;

(4)调节滑动变阻器的滑片使电压表示数不变;

(5)当电压相等时,通过导体的电流跟导体的电阻成反比.

单项选择题
问答题


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