题目内容
如图所示是示波管的原理示意图。电子从灯丝发射出来的经电压为U1的电场加速后,通过加速极板A上的小孔O1射出,沿中心线O1O2进入MN间的偏转电场,O1O2与偏转电场方向垂直,偏转电场的电压为U2,经过偏转电场的右端P1点离开偏转电场,然后打在垂直O1O2放置的荧光屏上的P2点。已知平行金属极板MN间的距离为d,极板长度为L,极板的右端与荧光屏之间的距离为L′。不计电子之间的相互作用力及其所受的重力,且电子离开灯丝的初速度可忽略不计。(电子的质量为m,电量为e)求:
(1)电子通过小孔O1时的速度大小V0;
(2)电子在偏转电场中的加速度大小a;
(3)电子通过P1点时偏离中心线O1O2的距离y;
(4)电子离开偏转电场时的动能Ek;
(5)若O1O2的延长线交于荧光屏上O3点,而P2点到O3点的距离称为偏转距离Y(单位偏转电压引起的偏转距离,即Y/U2称为示波管的灵敏度),求该示波管的灵敏度。![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241148553414441.jpg)
(1)电子通过小孔O1时的速度大小V0;
(2)电子在偏转电场中的加速度大小a;
(3)电子通过P1点时偏离中心线O1O2的距离y;
(4)电子离开偏转电场时的动能Ek;
(5)若O1O2的延长线交于荧光屏上O3点,而P2点到O3点的距离称为偏转距离Y(单位偏转电压引起的偏转距离,即Y/U2称为示波管的灵敏度),求该示波管的灵敏度。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241148553414441.jpg)
(1)
(2)
(3)
(4)
(5)![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114855435718.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114855357583.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114855373928.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241148553881193.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241148554191642.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114855435718.gif)
(1)
(3分)
(2)
(3分)
(3)
(3分)
(4)根据动能定理:
(2分)
(2分)
(5)
(2分)
(2分)
(1分)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114855451510.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114855357583.gif)
(2)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114855482575.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114855497154.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114855513563.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114855529543.gif)
(4)根据动能定理:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114855544683.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114855560714.gif)
(5)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114855575667.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114855591730.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114855435718.gif)
![](http://thumb2018.1010pic.com/images/loading.gif)
练习册系列答案
相关题目