北京邮电大学大学物理实验绪论

可编辑修改精选全文完整版大学物理第六版上册北京邮电大学出版课后答案详解1、行驶的汽车关闭发动机后还能行驶一段距离是因为汽车受到惯性力作用[判断题] *对错(正确答案)答案解析：汽车具有惯性2、用如图所示的装置做“探究小车速度随时间变化的规律”实验：1．小车从靠近定滑轮处释放．[判断题] *对错(正确答案)3、马德堡半球实验测出了大气压，其大小等于760mm高水银柱产生的压强[判断题]对错(正确答案)答案解析：托里拆利实验最早测出了大气压强4、11．小敏学习密度后，了解到人体的密度跟水的密度差不多，从而她估测一个中学生的体积约为（）[单选题] *A．50 m3B．50 dm3(正确答案)C．50 cm3D．500 cm35、9．在某原子结构模型示意图中，a、b、c是构成该原子的三种不同粒子，能得出的结（）[单选题] *A.a和c数量不相等B．b决定原子种类C．质量集中在c上D．a和c之间存在吸引的力(正确答案)6、4．静止在水平地面上的物体受到向上的弹力是因为地面发生了形变．[判断题] *对(正确答案)错7、下列有关力做功的说法中正确的是（）[单选题]A.用水平力推着购物车前进，推车的力做了功(正确答案)B.把水桶从地面上提起来，提水桶的力没有做功C.书静止在水平桌面上，书受到的支持力做了功D.挂钩上的书包静止时，书包受到的拉力做了功8、1．与头发摩擦过的塑料尺能吸引碎纸屑。

下列与此现象所反映的原理相同的是（）[单选题] *A．行驶的汽车窗帘被吸出去B．挤压后的吸盘吸在光滑的墙上C．用干燥的双手搓开的塑料袋会吸在手上(正确答案)D．两个表面光滑的铅块挤压后吸在一起9、下列措施中，能使蒸发减慢的是（）[单选题]A．把盛有酒精的瓶口盖严(正确答案)B．把湿衣服晾在通风向阳处C．用电吹风给湿头发吹风D．将地面上的积水向周围扫开10、停放在水平地面上的汽车对地面的压力和地面对车的支持力是平衡力[判断题] *对错(正确答案)答案解析：相互作用力11、52．“凿壁偷光”原指凿穿墙壁，让邻舍的烛光透过来，后用来形容家贫而勤奋读书。

北京邮电大学音频信号光纤传输试验（北京邮电大学，北京市，100876）摘要：随着光纤通信技术的发展，一个以微电子技术、激光技术、计算机技术和现代通信技术为基础的超高速宽带信息网正在改变人们的生活。

光纤通信以其诸多优点将成为现代通信的主流，未来信息社会的一项基础技术和主要手段。

本文旨在使读者了解光纤通信的基本工作原理，熟悉半导体电光-光电元件的基本性能和主要特性的测试方法。

关键词：光纤通信;光电二极管SPD;信号放大中图分类号：[TN913.7]文献标识码：AOptical fiber transmission of audio signal(Beijing University of Post&Telecommunication, Beijing, 100876, China)Abstract：With the development of optical fiber communication technology, a microelectronic technology, laser technology, computer technology and modern communication technology-based ultra-high-speed broadband information network is changing people's lives. Optical fiber communication with its many advantages will become the mainstream of modern communication, the future of the information society and the main means of an underlying technology. This article aims to enable readers to understand the basic working principle of optical fiber communication, familiar with semiconductor electro-optic - Optoelectronics basic properties and main characteristics of the test methods.Keywords: Optical Fiber Communication; Photodiode; Signal amplification光导纤维是近40年发展起来的一项新兴技术，是现代光信息技术的重要组成部分。

The Report Of the College Physics ExperimentExperiment 1:optical lever mirror method to measure Young'smodulus of the metalPurpose:1. Master the principle of measuring the small length changes with optical levermirror.2.Learn how to eliminate the systematic errors with symmetric measurement.3.Learn how to estimate the errors to each measured value in accordance with theactual situation.4.Train to deal data with different methods and construction.Theory:Objects should engender deformation more or less by the external force. It is theelastic deformation which will disappear promptly after withdrawing the externalforce when the force is no more than a certain limits. The objects will restore arestituted internal stress after occurring elastic deformation.There is a section S, length L 0 of the equably rod- like (wire-like) material, whenit stretched by the pulling force F, it elongates L Δ, stress is measured as the force per unit cross sectional area ofS F ; and strain is the increase in length of unit length of LL Δ. According to Hook’s Law, the strain rod -like (wire-like)material burdened is proportional to the burdened stress:0ΔL L Y S F Fig. 1 the optical lever Where Y is the coefficient depended on the characterization of the materials .Themodulus is thenFig. 1 the optical leverknown as Young’s modulus (Y). and hence: LS FL Y Δ0 (1) This experiment is to measure the Young ’s modulus of a kind of model steel, in which F can be determined by the calculated weight of weight, sectional area S can be get by calculating the diameter of the wire measured with micrometer screw gouge, 0L can be measured by conventional measurement apparatus such as meter and so on. But L Δis difficult to measure accurately for its small length change used ordinary apparatus. So we choose amplification ——“optical lever mirror” to measure this small change L Δ. The optical lever mirror physical diagram is Fig. 1Fig.2 the principle of optical lever mirrorFig.2 is the principle chart of measuring the tiny length change by optical lever mirror. The left curled object is the optical lever mirror, M is a reflector, b is the so- called short – optical lever mirror arm length, O is fixed- side of b-side, the other side b will rise or fall when the measured object elongating or shortening, and change the direction of normal line of M. The original wire length is 0L , from the right adjusted telescope we can see the reading of scale imagine of M of 1n , while the steel is elongated, from the telescope we can see the reading of scale imagine of M: 2n . In this way, the tiny wire elongation is L Δ, the corresponding angle change of the optical Db MΔn=n-nOlever mirror is θ, and the reading change of scale imagine of M is 21Δn n n -=. Be reversible by the optical path that light lever angle should be θ2. Using the geometric method in Fig.2 we can get:bL ∆=≈θθtg (2) D n D n n ∆=-=≈1222tg θθ (3) Hence n Db L ∆=∆2 (4) Where 12n n n -=∆, equivalent to the displacement of the long arm of optical lever mirror. bD 2 is the magnification of optical lever mirror, as D >> b, so ∆n >> ∆L, that means we get linear amplification of the small amount, and enhance the measurement accuracy of L ∆.This measurement is known as amplification. This amplification has a wide range of applications in designing all kinds of testing equipment for its advantage of stable performance, high precision, linear amplification and so on.Taking into account the wire by the external force there is a lag effect of flexibility, as to say that the steel can’t be due immediately to the elongated length of i L (i i L L L ∆+=0) when it is elongated, but only to the elongation of i i L L δ-. Similarly, the steel can’t be reduced to the length of L i when once the stretching force of the wire has been reduced, but only reduced to i i L L δ+. Therefore the measured length of the wire by the experiment is not the actual elongated or contracted length. In order to eliminate the systematic errors by the lag effect of flexibility, the measurement should be included a symmetrical measurement process of increasing the tensile strength and reducing the tensile strength. To the experiment, we can get this to increase or reduce the weights, we can take average amount of the stretching of wire as long as increase or reduce a corresponding weight to eliminate the effects of lagged volume. That is:[]()()[]i i i i i i L L L L L L L L L L L ∆+=+∆++-∆+=+=0002121δδ减增Procedure:(1)Attach 2kg hanger for weights to end of the wire to remove any irregularities. Adjust the three foot screws under the Young’s modulu s chassis, and observe the standard ruler on the platform at the same time until the middle of the platform is at the level of state.(2)Regulate the location of the optical lever mirror. Take the optical lever mirror on the platform, the two front feet on the cross- platform, the rear foot on the cylindrical casing of the lower end of the fixed wire (the rear foot must be placed on the edge of the metal casing, but not on the location of the gap),and let the mirror of optical lever mirror to be basic vertical or slight angle, as shown in Fig. 1.(3)Adjust the telescope. Place the telescope about 2m away from the optical lever mirror. Loose the fixed screw of telescope and move up or down to let the mirror of optical lever mirror and the telescope are on the same height. Take aim at the mirror of optical lever mirror along the tube axis above the telescope. Shift the fixed position of the telescope until we can see the scale imagine from the optical lever mirror. And then observe from the eyepiece. Adjust the eyepiece to see the cross wire clearly and finally revolve the focusing hand wheel to flexible the telescope in the tube until we can see the ruler scale clearly from the telescope.(4)Observe the stretch change. Attach 2kg hanger for weights to the end of the wire as the beginning, and take the telescope reading of 0n . Load the measured wire with successive kilogram weights, taking the telescope reading after each addition ——76543210n ,n ,n ,n ,n ,n ,n ,n . Unload kilogram by kilogram, and read thetelescope at each stage ——01234567n ,n ,n ,n ,n ,n ,n ,n ''''''''. Note: Add or subtract the weight lightly to avoid a relatively large vibration. After adding or subtracting the weight, the wire will have a scalable micro-vibration, and we should read after the steel gradually becoming stable.(5)Measure the distance b from the front foot to the rear foot of optical lever mirror. Rent the 3 feet of the optical lever mirror in white paper. Draw the connection of the two front feet and then measure the vertical distance from the rear foot to theline with the vernier scale.(6)Measure the diameter of the wire at several points about 3-5 times along its length and find a mean value. This measurement must be done carefully with a micrometer screw-gauge and note the zero error each time.(7)Use meter ruler to measure the distance D from the plane mirror to the scale.(8)Use meter ruler to measure the original length of wire.(9)Notes①The wire must be clamped tightly at the both side, at one hand to reduce the system error, and at the other hand to avoid falling down to damage the test devices.②Don ’t move the telescope and the table in the measuring and reading process, or you must start measuring again.③Keep the measured wire straight so as to avoid misusing the measuring process for the elongation, resulting in measurement error.④Keeping the weight should be 1kg and don ’t touch the mirror in the measuring progress.⑤You must adjust the telescope in a certain scope to avoid damaging it.Data and the resultsKG △x=0.05 CM1.0F ＝仪镜尺距(he distance from the ruler to the mirror)D =150 mm ; △x仪= 0.05 CMThe wire length:L1(上读数) / cm L2(下读数）/cm 钢丝长度L/cm7.8 42.2 34.4The diameter of the wire:First record=0.02 mm ; △d仪=0.004 mm次数 1 2 3 4 5 6diameter ofthe wire/mm0.80 0.81 0.81 0.85 0.85 0.82光杠杆常数b=85.17 mm ;△b仪=0.002 mmgraphical method:F(*9.80N)10.0 11.5 13.0 14.5 16.5 17.5 19.0 20.5 22.0 23.5 25.0 26.5△x/c m 2.0152.1952.3552.512.7552.943.163.4053.613.834.0054.20The discuss of this experiment and my experiment:After this experiment I know that we should use plot to obtain the value of Y in this experiment.Eliminating the systematic errors in the experiment is also very important.I think that I have learned how to eliminate the systematic errors with symmetric measurement.I also have learned that how to estimate the errors to each measured value in accordance with the actual situation.To deal data withdifferent methods and construction is the purpose that we must get.。

北邮物理实验报告摘要：实验目的是通过实验得出物体的加速度与重力加速度之比。

采用摆钟法，并通过调节摆的角度和长度，利用摆的周期与物体的运动时间来计算相应的加速度值，取平均值得出最终结果。

实验结果为g/a=9.79±0.04。

实验原理：当物体做直线运动时，在没有空气摩擦、弹性变形和其他阻力的情况下，加速度表示为：a=F/m其中F是物体所受的合力，m是物体的质量，在地球上，物体所受的力主要有重力和摩擦力。

在忽略摩擦力的情况下，物体所受的合力F即为重力G。

因此：a=G/m根据牛顿第二定律，F=ma，可得出：G=mg其中g是地球的重力加速度。

因此，上式可以变为：a=g根据上式，可以知道物体的加速度与重力加速度之比为1，即g/a=1。

然而，在实际实验中，要通过测量物体的运动时间来得出相应的加速度值，因此需要通过简单的数学运算进行换算。

实验器材：摆钟、短绳、双向书、千分尺、手机秒表、支架、约1kg质量的物体。

实验步骤：1. 将物体用细绳系于摆钟的下端，调节摆的角度，使其能够完全在摆钟内摆动，并可靠地调整为在摆钟下端的任何位置开始。

2. 用手机秒表记录摆的周期和物体的运动时间，每个数据点都记录三次。

3. 更改摆钟的长度以减少周期的误差，从而更准确地调整加速度值。

实验结果：1. 第一次重复测量：g/a=10.032. 第二次重复测量：g/a=9.823. 第三次重复测量：g/a=9.789平均值：g/a=9.79±0.04结论：通过本次实验，我们成功地利用摆钟法求出了物体的加速度与重力加速度之比，并在数据处理中得出了相应的加速度值，结果表明g/a=9.79±0.04，与真实值十分接近。

实验结果具有一定的参考价值，同时也为物理实验的实践操作提供了一定的指导。

北京邮电大学物理实验课程设计实验报告大学物理实验课程设计实验报告姓名：郑友行学号：10211388 班级：309重力加速度的测定一、实验任务：精确测定北京地区的重力加速度二、实验要求：测量结果的相对不确定度不超过5%三、物理模型的建立及比较初步确定有以下六种模型方案：方法一、用打点计时器测量所用仪器为：打点计时器、直尺、带钱夹的铁架台、纸带、夹子、重物、学生电源等. 利用自由落体原理使重物做自由落体运动.选择理想纸带，找出起始点0，数出时间为t的P点，用米尺测出OP的距离为h，其中t=0.02秒×两点间隔数.由公式h=gt2/2得g=2h/t2，将所测代入即可求得g.方法二、用滴水法测重力加速度调节水龙头阀门，使水滴按相等时间滴下，用秒表测出n个（n取50—100）水滴所用时间t，则每两水滴相隔时间为t′=t/n，用米尺测出水滴下落距离h，由公式h=gt′2/2可得g=2hn2/t2.方法三、取半径为R的玻璃杯，内装适当的液体，固定在旋转台上.旋转台绕其对称轴以角速度ω匀速旋转，这时液体相对于玻璃杯的形状为旋转抛物面重力加速度的计算公式推导如下：取液面上任一液元A，它距转轴为x，质量为m，受重力mg、弹力N.由动力学知：Ncosα-mg=0（1）Nsinα＝mω2x（2）两式相比得tgα=ω2x/g，又tgα=dy/dx，∴dy=ω2xdx/g，∴y/x=ω2x/2g.∴g=ω2x2/2y. .将某点对于对称轴和垂直于对称轴最低点的直角坐标系的坐标x、y测出，将转台转速ω代入即可求得g.方法四、光电控制计时法调节水龙头阀门，使水滴按相等时间滴下，用秒表测出n个（n取50—100）水滴所用时间t，则每两水滴相隔时间为t′=t/n，用米尺测出水滴下落距离h，由公式h=gt′2/2可得g=2hn2/t2.方法五、用圆锥摆测量所用仪器为：米尺、秒表、单摆. 使单摆的摆锤在水平面内作匀速圆周运动，用直尺测量出h（见图1），用秒表测出摆锥n转所用的时间t，则摆锥角速度ω=2πn/t 摆锥作匀速圆周运动的向心力F=mgtgθ，而tgθ=r/h所以mgtgθ=mω2r由以上几式得：g=4π2n2h/t2. 将所测的n、t、h代入即可求得g 值.方法六、单摆法测量重力加速度在摆角很小时，摆动周期为：则通过对以上六种方法的比较，本想尝试利用光电控制计时法来测量，但因为实验室器材不全，故该方法无法进行；对其他几种方法反复比较，用单摆法测量重力加速度原理、方法都比较简单且最熟悉，仪器在实验室也很齐全，故利用该方法来测最为顺利，从而可以得到更为精确的值。

北邮物理实验报告北邮物理实验报告引言：物理实验是学习物理知识的重要环节，通过实际操作和观察，我们可以更深入地理解和应用所学的理论知识。

本文将介绍我在北邮进行的物理实验，并对实验结果进行分析和讨论。

实验一：测量重力加速度实验目的：通过自由落体实验测量地球上的重力加速度。

实验装置：简易自由落体装置、计时器、测量尺。

实验步骤：将自由落体装置固定在垂直方向上，从不同高度释放小球，用计时器测量小球下落所需的时间，并用测量尺测量下落的距离。

实验结果：通过多次实验，我们得到了不同高度下小球下落所需的时间和下落距离的数据。

数据处理：根据自由落体运动的公式，我们可以得到重力加速度的值，并与理论值进行比较。

实验讨论：通过与理论值的比较，我们可以评估实验误差的大小，并分析可能的原因。

同时，我们还可以探讨重力加速度与高度、质量等因素的关系。

实验二：测量光的折射率实验目的：通过测量光在不同介质中的折射角和入射角，计算出光的折射率。

实验装置：光源、平面镜、凸透镜、直尺、三棱镜。

实验步骤：将光源放置在透明介质中，通过平面镜和凸透镜使光线尽可能平行，然后让光线依次通过三棱镜。

利用直尺测量光线的入射角和折射角。

实验结果：通过实验测量得到了不同介质中光的入射角和折射角的数据。

数据处理：根据折射定律和光的折射率公式，我们可以计算出光的折射率，并与理论值进行比较。

实验讨论：在实验过程中，我们还可以观察到光的色散现象，并探讨折射率与介质的性质、入射角等因素的关系。

实验三：测量电流和电压实验目的：通过测量电流和电压的关系，验证欧姆定律。

实验装置：电源、电阻、导线、电流表、电压表。

实验步骤：将电源、电阻、导线连接在一起，用电流表测量电路中的电流，用电压表测量电路中的电压。

实验结果：通过实验测量得到了不同电压下的电流数据。

数据处理：根据欧姆定律，我们可以绘制出电流和电压的关系曲线，并通过斜率计算电阻的值。

实验讨论：在实验过程中，我们还可以探讨电流和电压的变化规律，以及电阻对电路的影响。

利用夫琅禾费衍射实现微小长度测量（北京邮电大学信息与通信工程学院）摘要：光的干涉和衍射现象为光的波动说提供了有力的证据，特别是光的衍射，不仅为光的本性的研究提供了重要的实验依据，而且深刻地反映了光子（或电子等其他量子力学中微观粒子）的运动受测不准关系的制约，也是光谱分析、晶体分析、全息技术、光学信息处理等近代光学技术的实验基础。

利用光电器件测量和探测光的干涉和衍射现象导致的光强在空间的分布变化情况，是近代技术中常用的光强测量方法之一。

关键词：夫琅禾费衍射；CCD；光强；微小长度Use of Fraunhofer Diffraction Achieve Small Length MeasurementZhangYongsheng( Beijing University of Posts and Telecommunications Information and Communication Engineering ) Abstract：Interference and diffraction of light wave theory of light phenomenon provides strong evidence, in particular the diffraction of light, not only for the nature of light study provides important experimental basis, but a profound reflection of photons (or other electronic quantum mechanics in microscopic particles) by the uncertainty relation of motion constraints, but also the spectral analysis, crystallographic analysis, holography, optical information processing and other modern optical technology experimental basis. Using the electro-optical device measurements and the probe light due to interference and diffraction of light intensity distribution in the space changes, the modern technology commonly used in measurement of light intensity.Keywords:Fraunhofer diffraction；CCD;Light intensity;Minimal length0 引言衍射,又称绕射,是一种波在传播过程中遇到障碍物或小孔后通过散射继续传播的现象。