题目内容
霍尔效应广泛应用于半导体材料的测试和研究中,例如应用霍尔效应测试半导体是电子型还是空穴型,研究半导体内载流子浓度的变化等。在霍尔效应实验中,如图所示,
宽为
cm,
长为4cm,
厚为
cm的导体,沿
方向通有3A的电流,当磁感应强度
的匀强磁场垂直向里穿过
平面时,产生了
V的霍尔电压,(已知导体内定向移动的自由电荷是电子),则下列说法正确的是
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241524346281839.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152433708370.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152433754206.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152433817394.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152433879332.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152433988490.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152433817394.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152434222489.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152434332506.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152434425474.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241524346281839.png)
A.在导体的前表面聚集自由电子,电子定向移动的速率![]() |
B.在导体的上表面聚集自由电子,电子定向移动的速率![]() |
C.在其它条件不变的情况下,增大![]() |
D.每立方米的自由电子数为![]() |
D
试题分析:已知导体内定向移动的自由电荷是电子,电流方向向右,所以电子定向移动方向向左,由左手定则可知电子所受洛伦兹力方向向上,上表面聚集自由电子,由E=U/d可知场强大小为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241524353141041.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241524355021266.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152435642551.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152435736965.png)
点评:难度中等,明确霍尔效应还是考查带电粒子在复合场中的运动,当电场力等于洛伦兹力时粒子匀速穿过,此种类型题还综合考查了欧姆定律、受力分析、U=Ed的问题
![](http://thumb2018.1010pic.com/images/loading.gif)
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