题目内容
在“测定金属的电阻率”的实验中,待测金属丝的电阻Rx约为
,实验室备有下列实验器材:
A.电压表V1(量程0~3V,内阻约为15
) B.电压表V2(量程0~15V,内阻约为75
)
C.电流表A1(量程0~3A,内阻约为0.2
) D.电流表A2(量程0~0.6A,内阻约为1
)
E.变阻器R1(0~100
,0.6A) F.变阻器R2(0~2000
,0.1A)
G.电池组E(电动势为3V,内阻约为0.3
) H.开关S,导线若干
(1)为减小实验误差,电流表应选用 ,电压表应选用 (填序号)。
(2)为减小实验误差,应选用图中 [填(a)或(b)]为该实验的电路原理图。
(3)按所选择的电路原理图把图中的实物图用线连接起来。![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241510304647348.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151029621384.png)
A.电压表V1(量程0~3V,内阻约为15
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151029684421.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151029824333.png)
C.电流表A1(量程0~3A,内阻约为0.2
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151029824333.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151029824333.png)
E.变阻器R1(0~100
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151029824333.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151029824333.png)
G.电池组E(电动势为3V,内阻约为0.3
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151029824333.png)
(1)为减小实验误差,电流表应选用 ,电压表应选用 (填序号)。
(2)为减小实验误差,应选用图中 [填(a)或(b)]为该实验的电路原理图。
(3)按所选择的电路原理图把图中的实物图用线连接起来。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241510304647348.jpg)
(1)D,A (2)b (3)图略
试题分析:(1)电流表和电压表读数超过量程的
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151030542327.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151030667794.png)
(2)待测电阻较小,所以选择电流表外接误差较小,故选b。
(3)电路连接如下图
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241510307764675.jpg)
点评:中等难度。测量电路的选择:当
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151030838653.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151030947659.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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