题目内容
一正弦交流电的电压随时间变化规律如图所示,由图可知,该交流电的周期是 s,频率是 Hz,有效值是 V,电压瞬时值的表达式为 ,每秒钟方向改变 次。
若将该交流电压加在
的电阻两端,则电阻消耗的功率是 W。![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241244543866149.png)
若将该交流电压加在
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124454277510.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241244543866149.png)
0.04s ;25Hz;
u="100sin" 50πt; 50次 ;50W
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241244544641198.png)
由图像可知,电压发生一个周期性的变化所花费的时间T=
s,f=
=25Hz,
V,u=u
sin
="100sin" 50πt,电流方向一个周期改变两次,一秒内有25个周期,所以每秒钟方向改变50次;若将该交流电压加在
的电阻两端,P=
50W
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124454495484.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124454511348.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241244545261137.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124454542404.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124454573572.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124454277510.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124454682663.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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