题目内容
欧姆定律适用于( )
A、金属导电 | B、电解液导电 | C、稀薄气体导电 | D、气体导电 |
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如图所示为某一电源的U-I曲线,由图可知( )
![](http://thumb.1010pic.com/pic3/upload/images/201405/36/42ab1b62.png)
![](http://thumb.1010pic.com/pic3/upload/images/201405/36/42ab1b62.png)
A、电源电动势为2 V | ||
B、电源内电阻为
| ||
C、电源短路时电流为6 A | ||
D、电路路端电压为1 V时,电路中电流为5 A |
某导体中的电流随其两端电压的变化如图所示,则下列说法中正确的是( )
![](http://thumb.1010pic.com/pic3/upload/images/201403/107/7562f06c.png)
![](http://thumb.1010pic.com/pic3/upload/images/201403/107/7562f06c.png)
A、加5V电压时,导体的电阻约是5Ω | B、加11V电压时,导体的电阻约是1.4Ω | C、由图可知,随着电压的增大,导体的电阻不断减小 | D、由图可知,随着电压的减小,导体的电阻不断减小 |
![](http://thumb.1010pic.com/pic3/upload/images/201406/70/c2ea78ed.png)
A、电阻R1<R2 | B、R1、R2串联的总电阻的I-U图象在区域Ⅰ | C、R1、R2串联的总电阻的I-U图象在区域Ⅱ | D、R1、R2串联的总电阻的I-U图象在区域Ⅲ |
![](http://thumb.1010pic.com/pic3/upload/images/201406/205/e4510539.png)
A、R1>R2 | B、R1<R2 | C、R1=R2 | D、不能确定 |
下列说法中错误的是( )
A、电流通过导体时,沿电流的方向电势逐渐降低 | ||
B、由I=
| ||
C、对一段确定的导体来说,
| ||
D、由R=
|
如图所示,电路中电压表的读数为25V,电流表的读数为2mA,则电压表的内阻为( )
![](http://thumb.1010pic.com/pic3/upload/images/201410/6/0cb60db7.png)
![](http://thumb.1010pic.com/pic3/upload/images/201410/6/0cb60db7.png)
A、12.5Ω | B、1250Ω | C、12.5kΩ | D、25kΩ |
如图所示为四个电阻的I-U关系图象.现将这四个电阻并联使用,则电功率最大的是( )![](http://thumb.1010pic.com/pic3/upload/images/201407/162/670c6162.png)
![](http://thumb.1010pic.com/pic3/upload/images/201407/162/670c6162.png)
A、R1 | B、R2 | C、R3 | D、R4 |