题目内容
闭合矩形线圈在匀强磁场中匀速转动,产生正弦交流电,电动势表达式为
V,电流表达式为
. 若把线圈匝数增加一倍,转速也增加一倍,其它条件不变. 则交流电的电动势与电流表达式分别为:( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824174830647741.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824174831084685.png)
A.![]() ![]() | B.![]() ![]() |
C.![]() ![]() | D.![]() ![]() |
C
试题分析:交流发电机产生的交变电动势的表达式
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241748337521380.png)
当N和n都增加一倍时,
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241748339701512.png)
由于线圈匝数增大一倍,所以线圈电阻增大一倍,故电流
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824174834251877.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824174834516751.png)
点评:此题要理解交流发电机产生的交变电动势的表达式
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241748347191383.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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