题目内容
某同学进行了“测定电源电动势和内电阻”的实验,将实验数据描绘得到如图(A)所示的图象。根据图像可得,该电源的电动势为______V,内电阻为_____Ω;若该同学在实验时采用如图(B)所示的电路,则电动势的测量值与真实值之间的关系为E测___E真,内电阻的测量值与真实值之间的关系为r测__r真。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242050479045010.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242050479045010.jpg)
20。3.0 1.0 < <
试题分析:由闭合电路欧姆定律可知:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824205047951549.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824205048638480.png)
而图象的斜率表示电源的内阻,故
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824205049355970.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242050505105477.jpg)
点评:本实验中的误差分析根据图象最容易掌握;但要注意分析清楚图象的变化及短路时电流接近真实值,这样才能确定出真实的图象.
![](http://thumb2018.1010pic.com/images/loading.gif)
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