题目
题型:不详难度:来源:
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220210-80375.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220210-55745.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220210-83515.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220211-80204.gif)
电压变化的周期为2r,如图乙所示.在t=0时,极板B附近的一个电子,质量为m、电荷量为e,受电场作用由静止开始运动.若整个运动过程中,电子未碰到极板A,且不考虑重力作用.
(1)若
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220211-52654.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220211-44573.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220210-80375.gif)
(2)若电子在
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220211-65202.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220211-72558.gif)
(3)若电子在第
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220211-20502.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220212-37720.jpg)
答案
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220212-31974.gif)
(2)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220212-89735.gif)
(3)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220212-42339.gif)
解析
(1)电子在0~
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220212-29443.gif)
加速度的大小
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220213-62372.gif)
位移
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220213-24078.gif)
在
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220213-75281.gif)
加速度的大小
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220213-12743.gif)
初速度的大小
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220213-86457.gif)
匀减速运动阶段的位移
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220213-93636.gif)
依据题意
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220214-37805.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220212-31974.gif)
(2)在
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220214-15467.gif)
速度增量
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220214-48279.gif)
在
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220214-45399.gif)
加速度的大小
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220214-21302.gif)
速度增量
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220215-47228.gif)
(a)当
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220215-92447.gif)
电子的运动速度
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220215-50134.gif)
解得
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220215-70736.gif)
(b)当
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220215-56493.gif)
电子的运动速度
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220216-17813.gif)
解得
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220216-51112.gif)
(3)电子在
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220216-12239.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220216-91329.gif)
电子在
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220216-31317.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220217-54894.gif)
由⑩式可知
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220217-35903.gif)
由⑿式可知
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220217-86519.gif)
依据题意
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220217-27452.gif)
解得
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220212-42339.gif)
核心考点
试题【(16分)制备纳米薄膜装置的工作电极可简化为真空中间距为的两平行极板,如图甲所示,加在极板A、B间的电压作周期性变化,其正向电压为,反向电压为,电压变化的周期为】;主要考察你对电荷在电场中的加速等知识点的理解。[详细]
举一反三
如图所示,空间有场强
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220144-65152.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220144-79346.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220144-28297.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220145-18315.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220145-89890.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220145-18315.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220145-83823.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220145-16379.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220145-12682.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220146-51085.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220146-28317.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220146-26045.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220146-18400.jpg)
(1)求碰撞前瞬间小球
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220145-83823.gif)
(2)若小球
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220146-51085.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220147-80148.gif)
(3)若施加恒力后,保持平板垂直于纸面且与水平面的夹角不变,在
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220146-28317.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220146-51085.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200112/20200112220141-80085.jpg)