题目内容
如图13-9-9所示是一个示波管工作的部分原理图,电子经加速后以速度v0垂直进入偏转电场,离开偏转电场时偏移量为y,两极板间距为d,电压为U,板长为L,每单位电压引起的偏移量(y/U)叫做示波管的灵敏度.为了提高灵敏度,可采用的办法是( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241200462191669.jpg)
图13-9-9
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241200462191669.jpg)
图13-9-9
A.增加两极板间的电势差U |
B.尽可能增加板长L |
C.尽可能减小极板间距d |
D.使电子的入射速度v0大些 |
BC
由L=v0t,y=
at2=
·
t2得
=
,由此可知正确选项为BC.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120046235226.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120046235226.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120046297423.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120046328346.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120046344525.gif)
![](http://thumb2018.1010pic.com/images/loading.gif)
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