题目内容
如图所示,在两个水平放置的平行金属板之间有竖直向下的匀强电场,电场强度为E。在两板之间及右侧有垂直纸面向里的匀强磁场,磁感应强度均为B。现有两个带电粒子![](http://thumb.1010pic.com/pic1/gzwl/wltk/ewebeditor/UploadFile080201/20084919512946.gif)
![](http://thumb.1010pic.com/pic1/gzwl/wltk/ewebeditor/UploadFile080201/20084919513174.gif)
![](http://thumb.1010pic.com/pic1/gzwl/wltk/ewebeditor/UploadFile080201/20084919513678.gif)
![](http://thumb.1010pic.com/pic1/gzwl/wltk/ewebeditor/UploadFile080201/20084919512946.gif)
![](http://thumb.1010pic.com/pic1/gzwl/wltk/ewebeditor/UploadFile080201/20084919513174.gif)
![](http://thumb.1010pic.com/pic1/gzwl/wltk/ewebeditor/UploadFile080201/20084919513978.gif)
![](http://thumb.1010pic.com/pic1/gzwl/wltk/ewebeditor/UploadFile080201/20084919514511.jpg)
解:如图所示,由于两粒子均能匀速通过平行板,则有: ![](http://thumb.1010pic.com/pic1/gzwl/wltk/ewebeditor/UploadFile080201/20084919514154.jpg)
两粒子的速度相等,通过平行板的时间相同,两粒子离开平行板后均做匀速圆周运动,轨迹如图所示。设粒子质量为M由
故有:
因为
,所以必相遇在A点,因为
为等边三解形,所以
粒子在磁场中转过
角,
粒子在磁场中转过60°角。 又由
得:
运动周期
运动周期
所以
注:计算题用其它解法,正确均给分。
![](http://thumb.1010pic.com/pic1/gzwl/wltk/ewebeditor/UploadFile080201/20084919514154.jpg)
![](http://thumb.1010pic.com/pic1/gzwl/wltk/ewebeditor/UploadFile080201/20084919514309.gif)
![](http://thumb.1010pic.com/pic1/gzwl/wltk/ewebeditor/UploadFile080201/20084919514290.gif)
![](http://thumb.1010pic.com/pic1/gzwl/wltk/ewebeditor/UploadFile080201/20084919514582.gif)
![](http://thumb.1010pic.com/pic1/gzwl/wltk/ewebeditor/UploadFile080201/20084919514379.gif)
![](http://thumb.1010pic.com/pic1/gzwl/wltk/ewebeditor/UploadFile080201/20084919514524.gif)
![](http://thumb.1010pic.com/pic1/gzwl/wltk/ewebeditor/UploadFile080201/20084919514989.gif)
![](http://thumb.1010pic.com/pic1/gzwl/wltk/ewebeditor/UploadFile080201/20084919514785.gif)
![](http://thumb.1010pic.com/pic1/gzwl/wltk/ewebeditor/UploadFile080201/20084919515872.gif)
![](http://thumb.1010pic.com/pic1/gzwl/wltk/ewebeditor/UploadFile080201/20084919512946.gif)
![](http://thumb.1010pic.com/pic1/gzwl/wltk/ewebeditor/UploadFile080201/20084919515582.gif)
![](http://thumb.1010pic.com/pic1/gzwl/wltk/ewebeditor/UploadFile080201/20084919513174.gif)
![](http://thumb.1010pic.com/pic1/gzwl/wltk/ewebeditor/UploadFile080201/20084919515632.gif)
![](http://thumb.1010pic.com/pic1/gzwl/wltk/ewebeditor/UploadFile080201/20084919512946.gif)
![](http://thumb.1010pic.com/pic1/gzwl/wltk/ewebeditor/UploadFile080201/20084919515902.gif)
![](http://thumb.1010pic.com/pic1/gzwl/wltk/ewebeditor/UploadFile080201/20084919515106.gif)
![](http://thumb.1010pic.com/pic1/gzwl/wltk/ewebeditor/UploadFile080201/20084919515228.gif)
![](http://thumb.1010pic.com/pic1/gzwl/wltk/ewebeditor/UploadFile080201/20084919515101.gif)
![](http://thumb2018.1010pic.com/images/loading.gif)
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