题目内容
三个灯泡连接如右图所示,且电路电压U保持一定,原来电键S断开,则接通电键S时( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824125130783797.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824125130783797.png)
A.![]() ![]() |
B.![]() ![]() |
C.![]() ![]() |
D.![]() ![]() |
C
当开关闭合时,L3连入电路跟L1并联,使得总电阻减小,干路电路增大,故L2灯变亮,由于电源电压不变,所以L1两端电压减小,故L1灯变暗
所以应该选C
所以应该选C
![](http://thumb2018.1010pic.com/images/loading.gif)
练习册系列答案
相关题目
题目内容
A.![]() ![]() |
B.![]() ![]() |
C.![]() ![]() |
D.![]() ![]() |