题目内容
一正弦交流电的电压随时间变化的规律如右图所示。由图可知( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241636212032596.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241636212032596.jpg)
A.该交流电的电压瞬时值的表达式为u=100sin25πt(V) |
B.该交流电的频率为4 Hz |
C.该交流电的电压的有效值为100![]() |
D.若将该交流电压加在阻值为R=100Ω的电阻两端,则电阻消耗的功率为50 W |
D
试题分析:由图可知,
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824163621374610.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824163621577727.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824163621733918.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824163621936843.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241636222011137.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241636225441061.png)
故选D.
点评:要根据交流电图象正确求解最大值、有效值、周期、频率、角速度等物理量,同时正确书写交流电的表达式.
![](http://thumb2018.1010pic.com/images/loading.gif)
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