题目内容
如图所示,在直角坐标系O-xyz中存在磁感应强度为
、方向竖直向下的匀强磁场,在(0,0,h)处固定一电量为+q(q>0)的点电荷,在xOy平面内有一质量为m(m未知),电量为-q的微粒绕原点O沿图示方向作匀速圆周运动。若微粒的圆周运动可以等效为环形电流,求:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241333451164395.jpg)
(1)若已知+q与-q的连线与z轴的夹角θ和静电力常量k,则此微粒所受的库仑力多大
(2)此微粒作匀速圆周运动的角速度ω;
(3)等效环形电流的电流强度I(已知重力加速度为g)。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133345085853.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241333451164395.jpg)
(1)若已知+q与-q的连线与z轴的夹角θ和静电力常量k,则此微粒所受的库仑力多大
(2)此微粒作匀速圆周运动的角速度ω;
(3)等效环形电流的电流强度I(已知重力加速度为g)。
(1)
(2)
(3)![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241333452571114.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133345148991.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133345179891.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241333452571114.png)
(1)(6分)该微粒受到的库仑力FE:
(2分),
(2分),
(2分)。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241333455225197.jpg)
(2)(8分)
,
,由几何关系
(2分),微粒沿在z轴方向上受力平衡
(2分),微粒在xoy平面内做圆周运动
(2分),联立,解得
,解得
(2分),
(3)(5分)微粒圆周运动的周期
(2分),等效电流强度
(3分)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133345319763.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133345397690.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133345148991.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241333455225197.jpg)
(2)(8分)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133345538587.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133345616454.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133345647590.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133345678807.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133345787931.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133345834969.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133345179891.png)
(3)(5分)微粒圆周运动的周期
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133345974614.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241333452571114.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
练习册系列答案
相关题目