题目内容
如图所示是等离子发电机示意图.磁感应强度B为O.5T,两极间距离为20cm,要使输出电压为220V.则等离子体的速度为______,a是电源的______极.
![](http://thumb.1010pic.com/pic2/upload/papers/20140610/201406102201404093200.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140610/201406102201404093200.png)
电场强度E=
.
稳定时,洛伦兹力与电场力相等,则qvB=qE,解得:
v=
=
=
m/s=2200m/s.
根据左手定则知,正电荷向上偏转,负电荷向下偏转,则上极板带正电,a是电源的正极.
故答案为:2200m/s,正.
U |
d |
稳定时,洛伦兹力与电场力相等,则qvB=qE,解得:
v=
E |
B |
U |
Bd |
220 |
0.5×0.2 |
根据左手定则知,正电荷向上偏转,负电荷向下偏转,则上极板带正电,a是电源的正极.
故答案为:2200m/s,正.
![](http://thumb2018.1010pic.com/images/loading.gif)
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