题目内容
如图所示,在真空中有一对平行金属板两极板间的电势差为500V。一个电荷量为
C的粒子从正极板的小孔无初速的进入匀强电场,到达负极板.这个粒子到达负极板时的动能为多少焦耳?(不计重力)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241147206491653.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114720634423.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241147206491653.gif)
Ek=1.6×10-15J
对粒子从正极板到达负极板只有电场力做功,由动理定律得
又
……………………………6分
得粒子到达负极板时的动能为
…………………………………………………………4分
………………………4分
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114720883680.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114720899257.gif)
得粒子到达负极板时的动能为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114720899534.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114720914750.gif)
![](http://thumb2018.1010pic.com/images/loading.gif)
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