题目内容
在如图所示的电路中,当可变电阻R的阻值增大时
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241144486421621.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241144486421621.gif)
A.AB两点间的电压增大; |
B.AB两点间的电压减小; |
C.通过R的电流I增大; |
D.通过R的电流I减少。 |
AD
当
增大时,
增大,
增大,有
,因
、
不变,
增大时,
减小;而
,因
、
不变,
减小,故
增大;由
,因
不变而
减小,则
减小;由
,因
增大而
减小,故
增大;由
,因
增大,
不变,则
增大;由
,因
减小,
增大,
减小。
可见,当
增大时,
增大,
减小,故选项A、D正确。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114448658204.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114448689250.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114448689226.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114448720511.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114448752212.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114448767185.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114448689226.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114448783214.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114448798476.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114448752212.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114448767185.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114448783214.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114448876345.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114448892430.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114448908218.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114448783214.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114448939220.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114449017498.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114448876345.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114448939220.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114449064352.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114449079520.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114449064352.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114449110224.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114449173230.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114449188444.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114448783214.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114449173230.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114449235216.gif)
可见,当
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114448658204.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114449266351.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114449282191.gif)
![](http://thumb2018.1010pic.com/images/loading.gif)
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