![](https://img.xkw.com/dksih/QBM/editorImg/2023/7/18/0dd406a4-d2d6-45ce-836e-22bdb00ee61c.png?resizew=447)
(2)用电流表和电压表测定电阻约为6Ω的均匀电阻丝的电阻率实验,电源是两节干电池。如图甲所示,将电阻丝拉直后两端固定在带有刻度尺的绝缘底座的接线柱a、b上,c是一个可沿电阻丝滑动的金属触头c,电压表连接在a、c之间,a、c之间的长度L可从刻度尺上读出。实验采用的电路原理图如图乙所示,电表均可视为理想表。
![](https://img.xkw.com/dksih/QBM/editorImg/2023/7/18/c917801a-ef2c-4d31-898f-90616a03a100.png?resizew=445)
①本实验电流表的量程选
②连接线路,闭合开关后,触头c调至一合适位置后不动,滑动变阻器触头自左向右移动的过程中,电压表读数
③滑动变阻器触头调至合适位置后不动,改变触头c位置,得到几组U、I、L数据,用
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb5bb9540f400d8f2e057e8510e19f09.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/171102a883b22fe6ca578efc8926f5b8.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/7/18/89d82cdc-c0d0-4dc9-8c3e-b0bca16a052a.png?resizew=176)
相似题推荐
A.电流表A1(量程0~0.6A,内阻约0.5Ω)
B.电流表A2(量程0~3A,内阻约0.1Ω)
C.电压表V1(量程0~3V,内阻约10kΩ)
D.电压表V2(量程0~15V,内阻约25kΩ)
E.直流电源E(电动势4V,内阻不计)
F.滑动变阻器R1(阻值范围0~15Ω,允许通过的最大电流2.0A)
G.滑动变阻器R2(阻值范围0~2kΩ,允许通过的最大电流0.5A)
H.开关S、导线若干
(1)研究小组要测量圆柱体的长度和直径。步骤如下:用游标卡尺测量其长度如图甲所示,可知其长度为
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/6/79e49db4-17a0-49ce-be13-3aaee031d703.png?resizew=370)
(2)为完成实验并且使实验误差减小,电压从零开始可调以测得多组数据,应选择的仪器为
(3)请在如图所示的虚线框中画出测量的电路图
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/6/1bdc3d2e-b650-40d8-b91b-b06297f9e57c.png?resizew=215)
(4)被测圆柱体电阻的测量值与真实值比较,将
【推荐2】现有一段合金制成的金属丝。为测量该合金的电阻率,某同学先用伏安法测定金属丝的阻值Rx(约为10Ω),除了Rx、开关S、导线外,还有下列器材供选用:
A.电压表V1(量程0~3V,内阻约10kΩ)
B.电压表V2(量程0~15V,内阻约100kΩ)
C.电流表A1(量程0~1mA,内阻约10Ω)
D.电流表A2(量程0~0.6A,内阻约0.5Ω)
E.电源(电压3.0V,额定电流0.5A,内阻不计)
F.滑动变阻器R0(阻值范围0~5Ω,额定电流2A)
(1)为使测量尽量准确,电压表选用
(2)测量Rx阻值的实验电路图应该选择
A. B.
C.
D.
(3)该同学选择器材、连接电路和操作均正确,从实验原理上看,待测电阻测量值
(4)若流经金属丝的电流为I,金属丝两端的电压为U,金属丝的直径和长度分别用D、L表示,则用D、L、I、U表示该合金电阻率的关系式为
待测金属丝:Rx(阻值约4 Ω,额定电流约0.5 A);
电压表:V(量程3 V,内阻约3 kΩ);
电流表:A1(量程0.6 A,内阻约0.2 Ω);
A2(量程3 A,内阻约0.05 Ω);
电源:E1(电源电压为3 V);
E2(电源电压为12 V);
滑动变阻器:R(最大阻值约20 Ω);
螺旋测微器;毫米刻度尺;开关S;导线。
![](https://img.xkw.com/dksih/QBM/2021/10/15/2829763873234944/2829889562820608/STEM/bde23e6f-5418-468f-97f2-a7e8b2ce030c.png?resizew=173)
(1)用螺旋测微器测量金属丝的直径,示数如图所示,读数为
(2)若滑动变阻器采用分压式接法,为使测量尽量精确,电流表应选
![](https://img.xkw.com/dksih/QBM/2021/10/15/2829763873234944/2829889562820608/STEM/63af2843-eb20-4adc-806c-283648bef077.png?resizew=213)
(1)甲队实验小组为了测量一横截面为圆形、粗细程度均匀的某金属合金的圆柱体的电阻率,使用游标卡尺(精度0.05mm)、螺旋测微器分别测量该圆柱体的轴长和直径,如下图所示,则该金属圆柱体的轴长L=
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/23/9883b7b9-db6f-4f21-a597-6230a71781ed.png?resizew=103)
(1)用米尺测出其长度为L;
(2)用螺旋测微器测得其直径为d,如图1,可知其直径为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21f3bf70722b22983c120d008d097602.png)
(3)为使得电压可以从零开始测量,该小组的人员从下列器材中挑选了一些元件,设计了一个电路,重新测量这段导线(图中用
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce2581ae160692cd7e2686226fe5e2c6.png)
A.电源E(电动势为3.0V,内阻不计)
B.电压表V1(量程为0~3.0V,内阻约为2kΩ)
C.电压表V2(量程为0~15.0V,内阻约为6kΩ)
D.电流表A1(量程为0~0.6A,内阻约为1Ω)
E.电流表A2(量程为0~3.0A,内阻约为0.1Ω)
F.滑动变阻器R1(最大阻值10Ω,额定电流2.0A)
G.滑动变阻器R2(最大阻值1kΩ,额定电流1.0A)
H.开关S一个,导线若干
(4)为提高精度,设计电路图,并画在方框中
![](https://img.xkw.com/dksih/QBM/2023/11/19/3371191834099712/3371212584812544/STEM/302481c023e1442f815fe311786c8dc7.png?resizew=173)
(5)某次测量时,电压表示数为U,电流表示数为I,则该铜芯线材料的电阻率表达式为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0047f659c182291c84c224df6b5e993f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0047f659c182291c84c224df6b5e993f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0047f659c182291c84c224df6b5e993f.png)
D滑动变阻器R(0一5
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0047f659c182291c84c224df6b5e993f.png)
表一
次数 | 1 | 2 | 3 | 4 | 平均值 |
d/mm | 0.351 | 0.35 | 0.351 | 0.349 |
表二
次数 | 1 | 2 | 3 | 4 | 5 | 6 |
U/V | 0.42 | 0.78 | 1.00 | 1.47 | 1.80 | 2.26 |
I/A | 0.08 | 0.14 | 0.18 | 0.26 | 0.32 | 0.40 |
(1)某同学用螺旋测微器在金属丝的不同位置测量直径,读数记录在表一中,其中第
(2)该同学将测量Rx实验的数据记录在表二中,根据所给信息推测,其采用的电路是右图中的
A.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/21/cd60353c-4cba-4318-bef8-c7fb5de910f3.png?resizew=123)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/21/b29026a6-35ed-443f-b37c-d123f3b0f93e.png?resizew=123)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/21/822aa918-8d68-40bc-a8d4-5e6cc209e4e9.png?resizew=123)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/21/d0b553ce-fb08-4f1b-8fc3-eb1f33e0f9cf.png?resizew=122)
(3)根据所给信息可估算出待测金属丝的电阻率为
A.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a2902bd5b8b9f47c48d03de788316d8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a4a159ab9b2b68f27a3874f8072a8f13.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83c47b9364343d018d1384dca4c0fc51.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c6c621d966619d037c9a8c09d9c7b77.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aaf3a1e976dc7ccea4600a8ad1121760.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce2581ae160692cd7e2686226fe5e2c6.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/30/53d9587a-f747-4550-b7bd-ece23c801233.png?resizew=158)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/30/4b4952b1-c68e-4640-abcb-03485d47aa8a.png?resizew=217)
(1)根据图甲与图乙,该金属丝的直径
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c98c59cd4749afdd21e73529fc84323.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67c1313842b62428737610b14806d883.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cffa35373ec4e4684107b42adb7a5161.png)
(2)实验过程中,有一位同学提出只用一个电流表的实验方案,先将一段直电阻丝两端固定在两个接线柱上,紧靠电阻丝旁边固定一把刻度尺,且刻度尺的0刻度线与电阻丝的一端正好对齐,实验电路如图丙所示。所使用的电源输出电压为4V,电流表量程为200mA,滑动变阻器最大阻值为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4de49b9b4621a90d07ea99ae6c1cc75.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/30/e4ec7c75-8634-41f1-8841-c6920f92fed9.png?resizew=608)
A.将实验器材按照正确方式连接好电路;
B.调节电阻箱的阻值为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d6f46462975f5221ad20add1a202b840.png)
C.闭合开关S,调节滑动变阻器,使电流表示数为150mA;
D.然后改变金属夹的位置,不断向某方向移动,同时减小电阻箱的阻值,使电流表的示数保持150mA不变,记录接入电路电阻丝的长度x及电阻箱阻值R;得出多组数据,作出
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7fb9baada5e5b1454b39fdb5e8b43ef.png)
E.根据图像和测量的直径求得金属丝的电阻率
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b30db97c39edcede2f0e7d4e075fecec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/86ebba6ed1add0fe647c0226614b9290.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/171102a883b22fe6ca578efc8926f5b8.png)
(1)连接好电路后,小明合上开关
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e097c8d4c948de063796bd19f85b3a9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fd5f9ecb870fedb5b9a608d9ca2f911.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f1ac49b4139636fb1809fe970b23a87.png)
(2)保持
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e097c8d4c948de063796bd19f85b3a9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f833a7beb83820ecede0234c671f1878.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d1a0fd1ad044a9ecfcba672779bd678.png)
利用以上测量的物理量表示该电阻丝的电阻,为
电阻丝的长度用
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c88d9142df6ba8e43c1a93bd04a1362.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c02bc0c74292b1e8f395f90935d3174.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce2581ae160692cd7e2686226fe5e2c6.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/5c02bc0c74292b1e8f395f90935d3174.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce2581ae160692cd7e2686226fe5e2c6.png)
![](https://img.xkw.com/dksih/QBM/2020/11/2/2584316536684544/2584412358057984/STEM/a3dcdf7d-7c5e-4553-9443-e28818e89fe5.png?resizew=487)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/171102a883b22fe6ca578efc8926f5b8.png)
![](https://img.xkw.com/dksih/QBM/2021/1/28/2645768132599808/2647198843297792/STEM/87182846-a744-46f7-961f-d9f84ebcde33.png?resizew=575)
(1)如图甲所示,用螺旋测微器测量金属丝的直径时,为了防止金属丝发生明显形变,同时防止损坏螺旋测微器,转动旋钮C至测砧、测微螺杆与金属丝将要接触时,应调节旋钮
(2)请在图丙中用笔画线代替导线将电路补充完整
(3)如图丁所示,实验数据已描在坐标纸上,请作出U-I图线并求出该金属丝的电阻值为
![](https://img.xkw.com/dksih/QBM/2021/1/28/2645768132599808/2647198843297792/STEM/eff93a0f-4614-483a-aa30-506a8e4e4a93.png?resizew=182)
(4)有人认为用图像法求金属丝的电阻是为了减小系统误差,他的观点是否正确?请说明理由