1 . 实验小组测量某弹性导电绳的电阻率。实验过程如下:
装置安装和电路连接。如图(a)所示,导电绳的一端固定,另一端作为拉伸端,两端分别用带有金属夹A、B的导线接入如图(b)所示的电路中。先闭合开关S1、S2,调节R,使电压表和电流表的指针偏转到合适的位置,记录两表的示数U0和I0。
(1)然后断开开关S2,电流表的示数
(2)多次拉伸导电绳,每次都测量并记录AB间的距离L和导电绳横截面积S,调节滑动变阻器R的滑片的位置,使电流表的示数为I0,记下此时的电压表示数U。绘制如图(c)所示的图像。已知图线的斜率为k、与纵轴的截距为d,则弹性导电绳的电阻率ρ==
(3)若考虑电流表的内阻,则(2)中的电阻率的测量值
(1)用螺旋测微器测量其直径如图所示,由图可知其直径D=
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/28/edc24032-77ca-489a-9b4b-2e20388d1888.png?resizew=182)
(2)某同学先用多用电表的电阻“×10”挡,按正确的操作步骤测量此圆柱体的电阻,发现指针偏转角度很小,则应将选择开关旋转到
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/28/8473971e-8a79-465f-8c5b-5d37876591a2.png?resizew=355)
(3)某同学想通过描绘伏安特性曲线来研究该电阻R,现有的器材及其代号和规格如下:
待测圆柱体电阻R:
电流表A1(量程0~4mA,内阻约50Ω);
电流表A2(量程0~30mA,内阻约30Ω)
电压表V1(量程3V,内阻约10kΩ);
电压表V2(量程15V,内阻约25kΩ);
直流电源E(电动势4V,内阻不计):
滑动变阻器R1阻值范围0~15Ω,允许通过的最大电流2.0A);
滑动变阻器R2阻值范围0.2kΩ,允许通过的最大电流0.5A);
开关S;导线若干
根据实验要求,滑动变阻器应选
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/28/6acff4cc-b992-4981-9f41-fcff1ca1748c.png?resizew=192)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20321c69d95af5e5a3adc104975a9a6a.png)
)。图甲为该组同学用绝缘材料制成的长度
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b46f68d57dfb24626ed4ec2c3b5ac388.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/29/915b8ea1-679b-435d-a515-a6e27f5a1ccb.png?resizew=550)
(1)装入污水样品前,需测量圆筒形盛水容器的内径,应使用图乙中游标卡尺的
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c98c59cd4749afdd21e73529fc84323.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9efa9fbcfb9595e2f031aa691db4564b.png)
(2)将污水样品装满圆筒形盛水容器后,用电阻可忽略、带有接线柱的金属圆片将两端密封,并用欧姆表测出该样品的电阻为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d02e8ca16e7f5da79d5dc4e4cc183a23.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce2581ae160692cd7e2686226fe5e2c6.png)
A.电源E(电动势约
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40d48358392978b7ee4d6d803533a9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f66de503c8055c43644b847eba74b50f.png)
B.电流表
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acf35aa115963656d885b6440d6caa2c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/74e07a0e678dd1c3218d52860fa4d06f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a9616d2a37245f6d4415633e947290d8.png)
C.电流表
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c9e65b2e896a5c2371ef4d17d58d2709.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20786232cf70d0040233ac324d43e462.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b3e95410f3b4fcb0cba425b521d1f67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ee5b7e91d647021b85a223fb0483b05a.png)
D.定值电阻
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9efc18a5bb2e53586331b2a58538a48b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90b2eb2730da730b1cfb9ae5dcfba2f3.png)
E.定值电阻
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19f20f21a9d50b61dac519a3ddab539d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/edc43f644f43444a05c0816cf9768c87.png)
F.开关S,导线若干
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/29/6ad9ae8d-9e9f-4686-af25-13b8bb15088d.png?resizew=180)
(3)经正确操作,读出电流表
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acf35aa115963656d885b6440d6caa2c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c9e65b2e896a5c2371ef4d17d58d2709.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f1ac49b4139636fb1809fe970b23a87.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d1a0fd1ad044a9ecfcba672779bd678.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/857dbf14258d4b32dfe4e2cc799f245d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b30db97c39edcede2f0e7d4e075fecec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9942091e83e1d59af01f499a0caee212.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/86ebba6ed1add0fe647c0226614b9290.png)
(4)若装入的污水样品中有气泡,这将会使测得的污水样品的电阻率
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/29/4704553a-ab04-4249-b798-cba9d97cb9e9.png?resizew=234)
(1)用图甲中的螺旋测微器测量电阻丝的直径d。先将电阻丝轻轻地夹在测砧与测微螺杆之间,当测微螺杆快接近电阻丝时,再旋转
(2)用图乙所示电路图测量电阻丝的电阻
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce2581ae160692cd7e2686226fe5e2c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be9b4a83b9aebebf29de0c4406ebf894.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/29/b4a7bd25-9c68-45c1-84b4-6312616ec9c8.png?resizew=535)
(3)第一次按图乙所示的电路测量,调节滑动变阻器的滑片,测得多组电压U及电流I的值;第二次将电压表改接在a、b两点测量,测得多组电压U及电流I的值,并作出如图丁所示的U-I图像。则第一次测量得到的图线是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce2581ae160692cd7e2686226fe5e2c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/171102a883b22fe6ca578efc8926f5b8.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/29/19d5c69e-f6c4-420f-b70a-96b621a23c9b.png?resizew=278)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/19/8d38233f-689a-41f0-9b6e-a01c9a2cb802.png?resizew=465)
(1)用毫米刻度尺测量接入电路中的金属丝的有效长度L,再用螺旋测微器测量金属丝的直径D,如图甲所示,则
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a6d85799453899836bc34ad276ec80e.png)
(2)该同学接着用欧姆表粗测该金属丝的电阻,他进行了如下操作:先用“
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d55519bd96aba05e6f1533ddc7bb63fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aaf3a1e976dc7ccea4600a8ad1121760.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eebdb972b35aaa81a6662aaf8db1c282.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67c1313842b62428737610b14806d883.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cffa35373ec4e4684107b42adb7a5161.png)
(3)若用伏安法测量该金属丝的阻值,电路如图丙所示。除电源(电动势为4V,内阻不计)、电流表A(量程为30mA,内阻约
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d941822843eff28c70023ea38051c307.png)
A.电压表
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48fade4e14bf5845ff14f9e95bb6bfef.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ad53b547e11f3e4719a70a4b9564cc8.png)
B.电压表
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b40f1d184152aa3954752ed70e7d1612.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c94435abd92f9e157066cfb7f4e1b514.png)
C.滑动变阻器
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9efc18a5bb2e53586331b2a58538a48b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3268ee21400e819481400197ea8dc736.png)
D.滑动变阻器
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19f20f21a9d50b61dac519a3ddab539d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db2d4775108dbaaf447c51fe18b088c8.png)
(4)若某次测量中,电压表和电流表示数分别为U和I,请用上述直接测量的物理量(D、L、U、I)写出金属丝的电阻率
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/171102a883b22fe6ca578efc8926f5b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b30db97c39edcede2f0e7d4e075fecec.png)
6 . 小李同学在“测定金属的电阻率”实验中。
(1)因电表内阻未知,用如图甲所示的电路来判定电流表该内接还是外接。正确连线后,合上开关S,将滑动变阻器的滑片P移至合适位置。单刀双掷开关K掷到1,电压表的读数U1=1.65V,电流表的示数如图乙所示;将K掷到2,电压表和电流表的读数分别为U2=1.75V,I1=0.33A.由此可知应采用电流表
(2)完成上述实验后,小李同学进一步尝试用其他方法进行实验:
此时所用测量仪器均已校准。待测金属丝接入电路部分的平均长度为50.00cm。
①用螺旋测微器测量金属丝的直径如丙图所示。
②用伏安法测金属丝的电阻Rx,实验所用器材为:电池组(电动势3V,内阻约1Ω)、电流表、电压表、滑动变阻器R(0~20Ω,额定电流2A)、开关、导线若干。小李同学利用以上器材正确连接好电路,进行实验测量,记录数据如下:
次数 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
U/V | 0.10 | 0.30 | 0.70 | 1.00 | 1.50 | 1.70 | 2.30 |
I/A | 0.020 | 0.060 | 0.160 | 0.220 | 0.340 | 0.460 | 0.520 |
图丁是测量Rx的实验器材实物图,图中已连接了部分导线,滑动变阻器的滑片P置于变阻器的一端。请根据上述表格的实验数据,补充完成图丁中实物间的连线
③小李同学在坐标纸上建立U、I坐标系。如图戊所示,图中已标出了与测量数据对应的坐标点。描绘出UI图线。由图线得到金属丝的阻值Rx可以估算出金属丝电阻率约为
A.1×10-2Ω·m B.1×10-3Ω·m C.1×10-6Ω·m D.1×10-8Ω·m
A.电压表V1(量程0~3 V,内阻约为15 kΩ);
B.电压表V2(量程0~15 V,内阻约为75 kΩ);
C.电流表A1(量程0~3 A,内阻约为0.2 Ω);
D.电流表A2(量程0~0.6 A,内阻约为1 Ω);
E.滑动变阻器R1(0~10 Ω,0.6 A);
F.滑动变阻器R2(0~2 000 Ω,0.1 A);
G.电池组E(电动势为3 V);
H.开关S,导线若干。
(1)为减小实验误差,应选用的实验器材有
(2)为减小实验误差,应选用如图中
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/10/5b565a57-4dd2-4c4a-bff4-a4ad9f5504c3.png?resizew=487)
(3)若用毫米刻度尺测得金属丝长度为60.00 cm,用螺旋测微器测得金属丝的直径及两电表的示数如图丁所示,则金属丝的直径为
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/10/fbea23e4-9c77-4b41-9fd1-018263c71d83.png?resizew=388)
(4)金属丝的电阻率为
(1)该实验小组用刻度尺测量其长度L、螺旋测微器测量其直径D,某次直径测量结果如图所示:D=
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/26/e2d7817a-e560-4196-899d-a43fdeea698e.png?resizew=194)
(2)实验使用的滑动变阻器的阻值为0~20Ω,请将如图实际测量电路补充完整
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/26/e094ef6f-e97c-4754-b122-3308f4d1a3e1.png?resizew=259)
(3)闭合开关前,滑动变阻器的滑片应置于
(4)某次实验时,电压表的示数为U,电流表的示数为I,用实验测量的物理量L、D、U、I表示电阻率,则表达式为ρ=
(1)先用螺旋测微器测量金属丝的直径,示数如图甲所示,则金属丝的直径
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c98c59cd4749afdd21e73529fc84323.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21f3bf70722b22983c120d008d097602.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/27/b3621097-a339-4014-98c1-2479bdb9b955.png?resizew=162)
(2)要测量金属丝的电阻,小组成员先用多用电表欧姆挡粗测金属丝的电阻,选用
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/461349d280f65b49e0d38b4617dcec64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cffa35373ec4e4684107b42adb7a5161.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/19/9b6f4eab-9328-44ce-9a26-e126bf799e93.png?resizew=372)
(3)要精确测量金属丝的电阻,小组成员设计了如图丙所示电路,已知定值电阻阻值为R0,两个电流表:一个量程为Ia、内阻为ra,另一个量程为Ib、内阻为rb,Ia=2Ib调节滑动变阻器,使两电流表的指针偏转角度均较大,当电流表A1的示数为I1时、电流表A2的示数为I2,若金属丝的长度为L,则测得金属丝的电阻率
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b30db97c39edcede2f0e7d4e075fecec.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/19/5491c34f-a529-4691-ac07-fa85443432e1.jpg?resizew=152)
(1)某同学使用螺旋测微器测定其直径
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cacb0f0a5ab6f3cd9e215af4eef09082.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/18/b76ed99a-2b8f-4a4a-add9-4a510b2ff30a.png?resizew=257)
(2)某同学使用多用电表欧姆挡粗测其电阻,他首先将选择开关置于“X10”倍率,接着将两支表笔短接,旋转欧姆调零旋钮使指针指向0,然后将两表笔分别与该铅笔内芯两端接触,测其电阻时指针如下图所示,该同学接下来应该进行的操作是将选择开关置于“
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aaf3a1e976dc7ccea4600a8ad1121760.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eebdb972b35aaa81a6662aaf8db1c282.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/18/dc0eea7c-7e05-413b-b601-6ef05ed898e1.png?resizew=351)
(3)若该同学在上一步中正确操作后再次测量时指针如下图所示
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/18/f001e9f8-830b-4b92-a4ef-87a04aca7102.png?resizew=358)
则该铅笔内芯的电阻是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cffa35373ec4e4684107b42adb7a5161.png)
(4)若该铅笔内芯的直径为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cacb0f0a5ab6f3cd9e215af4eef09082.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c88d9142df6ba8e43c1a93bd04a1362.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4aa0df7f1e45f9de29e802c7f19a4f64.png)