题目内容
(8分)一课外小组同学想要测量一个电源(电动势E约为6.2V,内阻r约为2.2Ω)的电动势及内阻。准备的器材有:电流表A1(0-200mA,内阻是12Ω),电阻箱R(最大阻值9.9Ω),定值电阻R0=6.0Ω,一个开关和若干导线。
(1)请在方框中画出设计电路图。
(2)若记录实验中电阻箱的阻值R和对应的A1示数的倒数
,得到多组数据后描点作出R-
图线如图所示,则该电源的电动势E=______V,内阻r=_______Ω。(结果保留两位有效数字)![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241548301743087.jpg)
(1)请在方框中画出设计电路图。
(2)若记录实验中电阻箱的阻值R和对应的A1示数的倒数
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154829987296.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154829987296.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241548301743087.jpg)
(1)见解析(2)6.0;2.0
试题分析:(1)电路如图所示;
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241548302055493.jpg)
(2)根据并联电阻规律可得,电流表和电阻并联后总电阻为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154830221503.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154830345894.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154830423428.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154830533531.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154830626437.png)
点评:本实验是一道创新实验题,关键是对实验电路图原理以及闭合回路欧姆定律的理解,
![](http://thumb2018.1010pic.com/images/loading.gif)
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