题目内容
实验桌上摆放着甲“220V 25W”、乙“220V 300W”、丙“220V 500W”三只灯泡,小芳同学从中任选一只,正确使用多用电表测量它的阻值,如图所示,其测量值为____ Ω,她选用的是 灯泡(填“甲、乙或丙”),测量时流过灯泡的电流是从 流向 (填“a或b”)。![](http://thumb.1010pic.com/pic2/upload/papers/20140824/2014082414470317011106.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/2014082414470317011106.jpg)
160 ;乙; b a
试题分析:该同学使用的是欧姆表的
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824144703185342.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824144703248667.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824144703622608.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824144703669496.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824144703731426.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824144703778500.png)
点评:该题的关键是理解欧姆表的工作原理以及读数原理
![](http://thumb2018.1010pic.com/images/loading.gif)
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