题目内容
额定电压为U0的电灯,其均匀灯丝常温下的电阻为R,下列说法中正确的是
A.常温下,若将灯丝均匀拉长为原来的10倍,则电阻变为10R |
B.常温下,若将灯丝从中点对折起来,电阻变为![]() |
C.给灯丝加上从0到U0逐渐增大的电压,其![]() |
D.将灯丝温度降低到接近绝对零度时其电阻会突变为0 |
B
试题分析:一根粗细均匀的导线均匀拉长10倍,长度增加原来的10倍,同时横截面积变原来的
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005250344333.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005250360362.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005250376338.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005250391303.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005250329389.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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