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用同种材料制成的粗细均匀的某段金属导体,对于其电阻大小下列说法正确的是( ) A...
用同种材料制成的粗细均匀的某段金属导体,对于其电阻大小下列说法正确的是( )
A.当导体两端电压和通过导体的电流为零时,导体的电阻为零
B.当导体被均匀拉长至原来的二倍时,他的电阻减小为原来的一半
C.电阻是导体本身的一种性质,所以温度无论如何变化,电阻也不可能变为零
D.电阻是导体本身的一种性质,与电压和电流无关
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