利用数字多用表的电压挡可替代普通指针式电压表,数字电压表有很多优点,比如读数直接明了、不怕超量程等,最突出的优点是数字电压表内电阻极大,几乎没有分流作用,可以说是现实中的“理想电压表”。如图甲是利用数字电压表测量金属丝电阻率的电路图,
是被测金属丝,定值电阻阻值为
,
是一只单刀双掷开关。![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c98c59cd4749afdd21e73529fc84323.png)
______
。
,将单刀双掷开关
的阐刀掷于“a”,记录下此时数字电压表的读数
,滑动变阻器触头不动,将单刀双掷开关
的闸刀掷于“b”,记录下此时数字电压表的读数
,已知定值电阻阻值为
,则通过被测金属丝的电流![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80854e09068afb6145519074e575ac36.png)
______ ,金属丝电阻的测量值![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67c1313842b62428737610b14806d883.png)
______ 。(均用
、
、
表示)
(3)为了减小偶然误差,通过调整滑动变阻器触头,得到多组
、
数据,测得金属丝的电阻
,则电阻率![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b30db97c39edcede2f0e7d4e075fecec.png)
______
。(保留3位有效数字)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce2581ae160692cd7e2686226fe5e2c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be9b4a83b9aebebf29de0c4406ebf894.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/779629f16056a50f4c06e3996d8e1c82.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c98c59cd4749afdd21e73529fc84323.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21f3bf70722b22983c120d008d097602.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/910f1655703721b51006b887a2394b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/779629f16056a50f4c06e3996d8e1c82.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad7cd923bcf84bf5893c32d5fd99136d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/779629f16056a50f4c06e3996d8e1c82.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07e54197c09bb925fa0b5dbf751d6380.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be9b4a83b9aebebf29de0c4406ebf894.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80854e09068afb6145519074e575ac36.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67c1313842b62428737610b14806d883.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad7cd923bcf84bf5893c32d5fd99136d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07e54197c09bb925fa0b5dbf751d6380.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be9b4a83b9aebebf29de0c4406ebf894.png)
(3)为了减小偶然误差,通过调整滑动变阻器触头,得到多组
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad7cd923bcf84bf5893c32d5fd99136d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07e54197c09bb925fa0b5dbf751d6380.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1460e5c820e03c50802a47c0079e8ae3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b30db97c39edcede2f0e7d4e075fecec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9942091e83e1d59af01f499a0caee212.png)
更新时间:2024-05-26 13:55:02
|
【知识点】 测量电阻丝电阻率的数据处理方法
相似题推荐
实验题
|
较易
(0.85)
名校
【推荐1】某同学欲测量一阻值大约为
,粗细均匀的金属线的电阻率。
(1)用游标卡尺测得该材料的长度L如图甲所示,读数![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f15ff9c3ecf9b5aef83fb417cbc4392.png)
______
,用螺旋测微器测得该材料的直径D如图乙所示,读数![](https://staticzujuan.xkw.com/quesimg/Upload/formula/878add2429436953fa0d32eff02de5df.png)
______
。
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/21/4c628396-bc1b-4d71-b074-51e9e62e314d.png?resizew=570)
(2)设测得导电材料的电阻为R,导电材料的长度为L,导电材料的直径为D,求得导电材料的电阻率为______ (用R、L、D三个物理量表述)。
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/510a282f9101ebd5713bb2012ea1fb21.png)
(1)用游标卡尺测得该材料的长度L如图甲所示,读数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f15ff9c3ecf9b5aef83fb417cbc4392.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21f3bf70722b22983c120d008d097602.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/878add2429436953fa0d32eff02de5df.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21f3bf70722b22983c120d008d097602.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/21/4c628396-bc1b-4d71-b074-51e9e62e314d.png?resizew=570)
(2)设测得导电材料的电阻为R,导电材料的长度为L,导电材料的直径为D,求得导电材料的电阻率为
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【推荐2】某同学用多用电表粗测某种材料的电阻率,主要操作如下:
![](https://img.xkw.com/dksih/QBM/editorImg/2022/7/3/46dde00b-2d09-4e91-b19d-c3e6d9aed7ef.png?resizew=99)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/7/3/6dfae2ce-b71d-431f-a970-6e43e963a0eb.png?resizew=279)
用毫米刻度尺测量材料的长度l;
用螺旋测微器测量材料横截面的直径如右图,由图可知其直径d为__________ mm;
用多用电表测量材料的电阻。
①机械调零后,将选择开关旋至电阻挡“×10”位置;
②将红、黑表笔短接,调节欧姆调零旋钮,使欧姆表指针对准电阻的________ 处(填 “0刻线”或“∞刻线”);
③把红、黑表笔分别与材料的两端相接,此时多用电表的示数如右图所示;
④为了使金属丝的阻值读数能够再准确一些,将选择开关旋至电阻挡______ 位置(填“×1”或“×100”),重新进行_________ ,读出材料的电阻R。
⑤计算材料的电阻率,计算式为ρ=____________ 。(用题中字母表示)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/7/3/46dde00b-2d09-4e91-b19d-c3e6d9aed7ef.png?resizew=99)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/7/3/6dfae2ce-b71d-431f-a970-6e43e963a0eb.png?resizew=279)
用毫米刻度尺测量材料的长度l;
用螺旋测微器测量材料横截面的直径如右图,由图可知其直径d为
用多用电表测量材料的电阻。
①机械调零后,将选择开关旋至电阻挡“×10”位置;
②将红、黑表笔短接,调节欧姆调零旋钮,使欧姆表指针对准电阻的
③把红、黑表笔分别与材料的两端相接,此时多用电表的示数如右图所示;
④为了使金属丝的阻值读数能够再准确一些,将选择开关旋至电阻挡
⑤计算材料的电阻率,计算式为ρ=
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【推荐3】滑动变阻器由电阻丝绕制而成,某同学欲测量一滑动变阻器电阻丝的电阻率。
可供选择的实验器材如下:
待测滑动变阻器(
,
);
游标卡尺(20分度);
电流表
(量程
,内阻
),电流表
(量程
,内阻约
);
电压表
(量程
,内阻约
),电压表
(量程
,内阻约
);
电源(电动势为
,内阻未知);
电键及导线若干。
为了避免损坏滑动变阻器,该同学决定不对滑动变阻器进行拆解,而是进行了如下操作:
(1)该同学首先用游标卡尺测量了电阻丝螺线管的长度
及外径
,
(
表示电阻丝的直径);其中测外径
时卡尺示数如图1所示,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a6d85799453899836bc34ad276ec80e.png)
___________ mm;
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/24/e15a3dd0-635a-4353-8d25-4ee9f4008003.png?resizew=247)
(2)实验电路如图2所示,则电流表应选___________ ,电压表应选___________ ;闭合开关前,应将滑动变阻器触头
调至
端;闭合开关后,多次改变滑动变阻器触点的位置,并记录触点
到电阻丝螺线管
端的距离
及电压表和电流表对应的示数
、
;
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/24/b1e4c6ec-cd75-42cd-bc9e-737a1f84a894.png?resizew=165)
(3)分别以“
”和“
”为纵坐标和横坐标建立坐标系,并依据测量的多组数据描点连线,得到如图3所示的图线,且图线的斜率为
,纵截距为
。该同学又查明了电阻丝螺线管的匝数为
,则滑动变阻器电阻丝的电阻率![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b30db97c39edcede2f0e7d4e075fecec.png)
___________ (用
、
、
和
表示);图线明显不过坐标原点,其纵截距的物理意义为___________ 。
可供选择的实验器材如下:
待测滑动变阻器(
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/158d20214a56a0a0cc37a23a62c5c064.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/000fc5a7140553c3fc4b3e446287962e.png)
游标卡尺(20分度);
电流表
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acf35aa115963656d885b6440d6caa2c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6660208c18148678ba8d9dbbadef59bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71fa106dc6d4d3d20997e68b9235d0f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c9e65b2e896a5c2371ef4d17d58d2709.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b77e973a72860ef9fa58026648feb94.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8317ce80459839066d2a275c84ab0642.png)
电压表
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/46ad1a9cd19361d1f7a2340d76d50c80.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d64b26bd3eaeebadf07fef49e260282.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/951f5dfc2ee88b950c0a4322d9236ce4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c688d3183cdee79c0ce7d84a23a38c4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ec6ec06bd32883db9b4ea250b06d4313.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d4ec6f34b0ca53d7989359860af0ac9.png)
电源(电动势为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d64b26bd3eaeebadf07fef49e260282.png)
电键及导线若干。
为了避免损坏滑动变阻器,该同学决定不对滑动变阻器进行拆解,而是进行了如下操作:
(1)该同学首先用游标卡尺测量了电阻丝螺线管的长度
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c88d9142df6ba8e43c1a93bd04a1362.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9dfb7c0a3c4a19aad90ff55e1d6158d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c02bc0c74292b1e8f395f90935d3174.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a6d85799453899836bc34ad276ec80e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/24/e15a3dd0-635a-4353-8d25-4ee9f4008003.png?resizew=247)
(2)实验电路如图2所示,则电流表应选
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b52b4f24969673c863b5aff4fb6751ce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e105760638b22b26ff8bec4354255e4c.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/24/b1e4c6ec-cd75-42cd-bc9e-737a1f84a894.png?resizew=165)
(3)分别以“
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b763290c8cb341f8c5b268ccc22e61bc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b30db97c39edcede2f0e7d4e075fecec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c88d9142df6ba8e43c1a93bd04a1362.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/24/405eee4b-b8df-4ce7-a93a-e48508aeceae.png?resizew=167)
您最近一年使用:0次