大学物理实验B复习思考题

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大学物理实验思考题和分析题答案

大学物理实验思考题和分析题答案

为节省大家时间,特从网上搜相关答案供大家参考!〔按咱做实验顺序〕2.用模拟法测绘静电场【预习思考题】1.用电流场模拟静电场的理论依据是什么?模拟的条件是什么?用电流场模拟静电场的理论依据是:对稳恒场而言,微分方程及边界条件唯一地决定了场的构造或分布,假设两种场满足一样的微分方程及边界条件,那么它们的构造也必然一样,静电场与模拟区域内的稳恒电流场具有形式一样的微分方程,只要使他们满足形式一样的边界条件,那么两者必定有一样的场构造。

模拟的条件是:稳恒电流场中的电极形状应与被模拟的静电场中的带电体几何形状一样;稳恒电流场中的导电介质是不良导体且电导率分布均匀,并满足σ极>>σ介以保证电流场中的电极〔良导体〕的外表也近似是一个等势面;模拟所用电极系统与被模拟电极系统的边界条件一样。

2.等势线和电场线之间有何关系?等势线和电场线处处相互垂直。

3.在测绘电场时,导电微晶边界处的电流是如何流动的?此处的电场线和等势线与边界有什么关系?它们对被测绘的电场有什么影响?在测绘电场时,导电微晶边界处的电流为0。

此处的电场线垂直于边界,而等势线平行于边界。

这导致被测绘的电场在近边界处受边界形状影响产生变形,不能表现出电场在无限空间中的分布特性。

【分析讨论题】1.如果电源电压增大一倍,等势线和电场线的形状是否发生变化?电场强度和电势分布是否发生变化?为什么?如果电源电压增大一倍,等势线和电场线的形状没有发生变化,但电场强度增强,电势的分布更为密集。

因为边界条件和导电介质都没有变化,所以电场的空间分布形状就不会变化,等势线和电场线的形状也就不会发生变化,但两电极间的电势差增大,等势线的分布就更为密集,相应的电场强度就会增加。

2.在测绘长直同轴圆柱面的电场时,什么因素会使等势线偏离圆形?测绘长直同轴圆柱面的电场时测到的等势线偏离圆形,可能的原因有:电极形状偏离圆形,导电介质分布不均匀,测量时的偶然误差等等。

3.从对长直同轴圆柱面的等势线的定量分析看,测得的等势线半径和理论值相比是偏大还是偏小?有哪些可能的原因导致这样的结果?⑴偏大,可能原因有电极直径测量偏大,外环电极外表有氧化层产生附加电阻,电压标示器件显示偏大等;⑵偏小,可能原因有电极直径测量偏小,中心电极外表有氧化层产生附加电阻,电压标示器件显示偏小等。

大学物理复习思考题

大学物理复习思考题
(C)取决于刚体的质量、质量的空间分布和轴的位置;
(D)只取决于转轴的位置,与刚体的质量和质量的空间分布无关。
C
假设物体沿着半圆弧形轨道下滑,轨道是光滑的。则在下列说法中正确的是:
(A)它的加速度永远指向圆心
(B)它的速度匀速增加
(C)轨道弹力的大小不断增加
(D)它的合外力大小变化,方向永远指向圆心
一质点沿x轴运动其加速度a与时间的关系为 ,如果初始时质点在原点处的速度为零,则其速度V=___________。
一质点在 轴上运动,加速度为 , 时质点静止于原点, 时刻质点的位移和速度和分别为
一质点作简谐振动,其速度随时间变化的规律为ν=ωAcosωt,则质点的振动方程为:__________________________。
10/9
在磁感强度为 的均匀磁场里,放一个面积为 的600匝的线圈,在0.2 s内把线圈平面从平行于磁场方向的位置转过90°,而垂直于磁场方向。此过程中线圈内的平均感应电动势为_______________。
在某一过程中,系统向外作150J的功,吸了300J的热量,则其内能增加了
150J
在某一过程中,供应一系统500J热量,同时此系统向外作100J的功,系统内能增加了_____________。
, 0
一个点波源发射的功率为1.0W,在各向同性的不吸收能量的均匀介质中发出球面波距离波源1.0m处的波的强度为_______。
一横波沿X轴正方向传播,波的振幅为0.03m,波长为0.04m,波速为1ms-1,设波源为坐标原点,当t=0时波源振动位移恰在平衡位置且向负方向运动,平面波的波函数为_________。
《大学物理》复习思考题
一、填空题
填空题
答案

大学物理实验思考题和分析题答案

大学物理实验思考题和分析题答案

为节省大家时间,特从网上搜相关答案供大家参考!〔按咱做实验顺序〕2.用模拟法测绘静电场【预习思考题】1.用电流场模拟静电场的理论依据是什么?模拟的条件是什么?用电流场模拟静电场的理论依据是:对稳恒场而言,微分方程及边界条件唯一地决定了场的构造或分布,假设两种场满足一样的微分方程及边界条件,那么它们的构造也必然一样,静电场与模拟区域内的稳恒电流场具有形式一样的微分方程,只要使他们满足形式一样的边界条件,那么两者必定有一样的场构造。

模拟的条件是:稳恒电流场中的电极形状应与被模拟的静电场中的带电体几何形状一样;稳恒电流场中的导电介质是不良导体且电导率分布均匀,并满足σ极>>σ介以保证电流场中的电极〔良导体〕的外表也近似是一个等势面;模拟所用电极系统与被模拟电极系统的边界条件一样。

2.等势线和电场线之间有何关系?等势线和电场线处处相互垂直。

3.在测绘电场时,导电微晶边界处的电流是如何流动的?此处的电场线和等势线与边界有什么关系?它们对被测绘的电场有什么影响?在测绘电场时,导电微晶边界处的电流为0。

此处的电场线垂直于边界,而等势线平行于边界。

这导致被测绘的电场在近边界处受边界形状影响产生变形,不能表现出电场在无限空间中的分布特性。

【分析讨论题】1.如果电源电压增大一倍,等势线和电场线的形状是否发生变化?电场强度和电势分布是否发生变化?为什么?如果电源电压增大一倍,等势线和电场线的形状没有发生变化,但电场强度增强,电势的分布更为密集。

因为边界条件和导电介质都没有变化,所以电场的空间分布形状就不会变化,等势线和电场线的形状也就不会发生变化,但两电极间的电势差增大,等势线的分布就更为密集,相应的电场强度就会增加。

2.在测绘长直同轴圆柱面的电场时,什么因素会使等势线偏离圆形?测绘长直同轴圆柱面的电场时测到的等势线偏离圆形,可能的原因有:电极形状偏离圆形,导电介质分布不均匀,测量时的偶然误差等等。

3.从对长直同轴圆柱面的等势线的定量分析看,测得的等势线半径和理论值相比是偏大还是偏小?有哪些可能的原因导致这样的结果?⑴偏大,可能原因有电极直径测量偏大,外环电极外表有氧化层产生附加电阻,电压标示器件显示偏大等;⑵偏小,可能原因有电极直径测量偏小,中心电极外表有氧化层产生附加电阻,电压标示器件显示偏小等。

2022年春季大学物理实验复习思考题

2022年春季大学物理实验复习思考题

2022年春季大学物理实验复习思考题第一章误差、不确定度和数据处理的基本知识1、测量不确定度的概念是什么?如何对测量不确定度进行评定?怎样对测量结果进行报道?uA(某)S某S某n(某i某)2i1nn(n1)uB(某)仪仪C22uC(某)u(某)2Au(某)B(S某)(仪3)2(p=68.3%)2、测量结果有效数字位数是如何确定的?(1)不确定度的位数一般只取一位(而且只入不舍),若首位是1时可取两位。

相对不确定度为百分之几,一般也只取一、两位。

(2)不确定度决定了测量结果有效数字的位数,即测量结果的有效数字最后一位应与不确定度所在位对齐;若不确定度取两位,则测量结果有效数字的末位和不确定度末位取齐。

(3)有效数字尾数舍入规则:尾数“小于五则舍,大于五则入,等于五凑偶”,这种舍入法则使尾数舍与入的概率相同。

(4)同一个测量值,其精度不应随单位变换而改变。

3、作图法是如何处理数据的?(光速测量实验)(1)作图规则①作图一定要用坐标纸;②画坐标纸大小和确定坐标轴分度;③画出坐标轴;④数据点;⑤连线;⑥标注图名.(2)图解法求直线的斜率和截距求直线斜率和截距的具体做法是,在描出的直线两端各取一坐标点A (某1,y1)和B(某2,y2),则可从下面的式子求出直线的斜率a和截距b。

a某y某1y2y2y1,b21某2某1某2某1A、B两坐标点相隔要远一些,一般取在直线两端附近(不要取原来的测量数据点),且自变量最好取为整数。

4、逐差法是如何处理数据的?(牛顿环实验)实验2示波器的原理与应用1.从CH1通道输入1V、1KHz正弦波,如何操作显示该信号波形?2.当波形水平游动时,如何调节使波形稳定?3.如何测量波形的幅度与周期?4.调节什么旋纽使李萨如图稳定?5.当示波器出现下面不良波形时,请选择合适的操作方法,使波形正常。

(1)波形超出屏幕:;(2)波形太小:;(3)波形太密:;(4)亮点,不显示波形:可选答案:①调大“偏转因数(VOLTS/DIV)”;②调小“偏转因数”;③调大“扫描速率(TIME/DIV)”;④调小“扫描速率”;⑤水平显示置“A”(常规)方式;⑥水平显示置“某-Y”方式。

《大学物理》光学实验思考题(答案)

《大学物理》光学实验思考题(答案)

实验一:1:何谓自准法(平面镜法)?并画出其光路图?答:课本平P150倒数第二段。

光路图,图4-42.利用自准法,调节望远镜光轴与分光计转轴垂直,此时从望远镜内看到叉丝和叉丝像分别在什么位置,请画出图形。

同课后思考题一。

答:与上方叉丝重合,原因是凸透镜成像原理和镜面反射原理。

图见课本P157图4-123.实验过程中,三棱镜在载物台上的放置有何要求?调节载物台螺丝是应注意哪些问题?画图说明。

答:分光计要作精密测量,它必须首先满足下述两个要求:①入射光和出射光应当是平行光;②入射光和出射光的方向以及反射面和出射面的法线都与分光计的刻度盘平行.图见课本的P157图4-13实验二:1:何为等厚干涉?牛顿环属于薄膜干涉,在牛顿环中薄膜在什么位置。

答:课本P177. 牛顿环中薄膜是指在平凸透镜和平板玻璃之间的空气薄膜。

2.测量时,若实际测量的是弦长,而不是牛顿环的直径,则对测量结果有何影响?为什么?答:没有影响。

由于弦到圆心的距离都相等,由勾股定理知,测量直径和测量弦长实际上没有区别,事实上我们测量时也没有办法做到严格沿直径测量。

3.通过测量计算透镜的曲率半径R时,为什么不用(3)式而用(5)式。

答:因为平凸透镜与平面镜由于机械压力引起形变,使得牛顿环中心不是一个点而是一个小圆斑,所以难以确定环的几何中心及条纹级次。

实验三:1:何谓非定域干涉?答:当两个具有同频率,同振动方向,强度相差不大的两个光源发出的球面波在他们相遇的空间处处相干,这种干涉现象为非定域干涉。

2.分光板和补偿板的作用是什么?答:迈克耳孙干涉仪中分光玻璃板作用:产生两个具有同频率,同振动方向,初相相同,强度相差不大的两个光源。

迈克耳孙干涉仪中补偿玻璃板有两种作用,其一是补偿分光板因色散而产生的附加程差,为获得白光干涉条纹所必须;其二是补偿相同入射角不同入射面光线所产生的附加光程差,为获得同心圆形的等倾条纹所必须。

3.牛顿环和迈克尔逊干涉实验中观察到的都是圆形干涉条纹,他们意义的区别?答:实验四:1:为什么选择(b)状态(全暗状态)为仪器零点?此时偏振化方向有何特点?答:当检偏器的偏振化方向与角平分线相垂直时,视场曾现均匀暗的图像。

大学物理实验思考题答案(Coll...

大学物理实验思考题答案(Coll...

大学物理实验思考题答案(College physics experiment; thinkingquestion; answer)1. if the time can be measured as a swing cycle value? Why?A: no.. Because of a large random error measurement, multiple measurements can reduce random error.2. a radius of less than under the radius of disk disk in disk, and the center line, the discussion of three line pendulum cycle and no-load cycle is compared to the increase and the decrease or not? Explain the reason.Answer: quality when two disks for uniform distribution, compared with no-load, swing cycle will be reduced. Because if the two disc as a radius equal to the original lower disc, the disc inertia is less than I0 quality equal to that of the same diameter, according to formula (3-1-5), T0 will reduce the swing period.3. three line pendulum by air damping in the swing amplitude, more and more small, whether it will change the cycle? Great influence on the measurement result? Why?Answer: the decreasing cycle has little influence on the measurement results, because the measurement time is short.2 measurement of elastic modulus of metal wires1. what are the advantages of optical lever, how to improve the sensitivity of the optical lever measurement?A: the advantage is that it can measure the small length variation. To improve the vertical distance magnification is increasing the scale distance of D or properly reduce the optical lever before and after the foot of B, can improve the sensitivity, because the magnification of the optical lever is 2D/b.2. what is the disparity, how to judge and eliminate the disparity?Answer: eyes at the eyepiece to move up and down, if the scale level telescope crosshair scale and relative displacement, this phenomenon is called parallax, fine focusing handwheel can eliminate parallax.3. why use by experimental data processing method?Answer: the difference method is a basic method of experimental data processing, the essence is to make full use of the data from the experiment, is to reduce the random error, data averaging effect. Because of some experimental data, if the simple average value of each measurement, the measured values will eliminate all intermediate, only through two readings, equal to the actual single measurement. In order to maintain the advantages of multiple measurements, the general variable interval changes, the data is divided into two groups, two groups of successive difference and then calculate the average value of the difference.In experiment three, the statistical regularity of random error1. what is the histogram? What is the normal distribution curve of the two? And what is the relationship between the difference?Answer: to do n repeated measurements of a physical quantity under the same conditions, a series of measurements, find the maximum and minimum values, and then determine an interval, which contains all the measurement data, the interval is divided into several regions and the statistical measurement results appear in the M frequency of each interval. In order to measure the data as the abscissa and the frequency M as the ordinate, draw the area between the frequency and the corresponding height can be a rectangle, namely statistical histogram.If the number of measurements of the interval more smaller, while histogram will be close to a smooth curve, when the distribution of n tends to infinity is called the normal distribution, the distribution curve of normal distribution curve.2. if the measured data set, its discrete degree than the data in the table, which is S (x) is relatively large, the average value of the cycle is very different?Answer: (not a big gap, according to the characteristics, statistical regularity of random error. We know that when the number of measurements is large, the measurement data and the average error of plus or minus almost offset each other, and the algebraic error tends to zero.Measurement of thermal experiment four equivalent electric heating methodWhat are the conditions of the experiment and 1. must be the basic method? Sources of systematic error may have?Answer: the experimental condition is the system with no external large heat exchange, and the system (i.e. water) should be possible in the quasi-static process. The experimental method of electrothermal method.The main source of system error is a system of heat dissipation, and temperature correction often cannot fully compensate for the heat dissipation effect of the measurement. Not even other sources may be the temperature of the water, instead of using the local temperature temperature. The water temperature and the ambient temperature difference is large, so as to give the final temperature error correction. The temperature measurement error, power quality and other physical quantity.2. try a qualitative description of the following occurs during the experiment, the experimental result is too large or too small?(1) when mixing water is spilled;Answer: the experimental results will be too small. The water was spilled, namely water quality decrease, in the calculation of the mechanical equivalent of heat, but also to the quality of said horizontal water calculation, that the water quality does not change, but because of the water quality of waterreducing, heating, electric heating power in the same system, rising temperature than water when the temperature will not rise high water and not spill at the same heating power, should rise T degrees, and the water spilled after rising temperature should be T+ degrees T. Use Q = (cimiT), and the denominator bigger J smaller.The uneven stirring (2);Answer: between the position of J is too large, too small by the resistance wire and the thermometer into the distance and. Far away from the resistance wire, temperature display system ratio, uniform system of low temperature, T uniform temperature of the system, value should be T- T display thermometer, calculated by J=A/ theta, the denominator is smaller, J is bigger; from the resistance wire is near. The value should be T+ T display thermometer thus, the denominator bigger, smaller J.The (3) measured at room temperature is high or low.Answer:0. Theta is at room temperature, if the measured values measured by the delta theta, delta theta theta temperature value is 0+; the low delta theta theta, the measured temperature value 0- delta theta, in the calculation of temperature loss, dTi=k (Ti- 0), K with independent volume (k at room temperature and room temperature the initial temperature and cooling), only the cooling temperature and the cooling time, measured at room temperature is too high, dTi=k[Ti- (0+ delta theta theta)],second temperature in the loss of dTi is less than the actual value, T seconds at the end of the Ti= k[Ti- (sigma delta temperature loss 0+ Delta theta theta)]. This value is less than the actual value, because the temperature of heat dissipation caused by loss of delta Ti=Tf+ Tf "Tf", the temperature corrected: Tf = Tf - Delta Ti, Delta Ti is negative, when the measured value is less than the actual temperature, the smaller absolute value of delta Ti: Tf "=Tf+, Ti, Tf 8." smaller, smaller Delta T (which is T = Tf - Tf, Tf: early warming initial value),J, J and smaller.Experiment seven(1) the current correction table, if it is found that the modified milliammeters readings are always higher than standard gauge readings, the shunt resistance should be adjusted big or small? Why? Answer: should be small. Let the same standard reading meter circuit, which keeps the loop current constant, the shunt resistance value decreased after will receive more current, so that the current flowing through the modified table header modification decreases, the reading is reduced. (2) correction voltage meter, if it is found that the modification of the voltage meter reading is always lower than the standard gauge readings, pressure resistance should be adjusted in big or small? Why? Answer: should be small. Let the same standard reading meter circuit, which is added in the modified Ammeter voltage constant. Small resistance, total resistance modification table is reduced, through the modified milliammeter increases, which also increased reading. (3)prove that using an ohmmeter measuring resistance, if the head pointer is refers to the scale in the center of the dial, then the ohmmeter indication why is exactly equal to the internal resistance of the ohmmeter value. Answer: a head pointer full scale current is Ig, the head pointer refers to the center of the dial in the circuit when the current is I, according to the problem, when the internal table is Rg, resistance to be measured at Rx; according to the working principle of an ohmmeter, when the measured resistance Rx = 0,. That is, it can be Rx = Rg. So, the ohmmeter displays readings is the internal resistance of the ohmmeter.The principle and application of [eight] experimental oscilloscopeOneWhy can display analog oscilloscope signal path of rapid change? Answer: in the analog oscilloscope vertical deflection plate plus the observed signal voltage in the horizontal deflection plate plus the sawtooth wave (time linear change) signal voltage, so the tube axis of oscilloscope is equivalent to the Cartesian coordinate time axis, after a period of a sawtooth signal, electron beam at in the screen tube painted on the observed signal waveform of a trajectory. When a periodic sawtooth wave signal is greater than or equal to the cycle signal and its phase locked (synchronous), electron beam in the display screen tube painted on the same trajectory observed signal waveform, due to persistence of vision and screen the human eye afterglow, can be observed signal waveform. (2) in this experiment, to observe the pattern of Li Saru, why not longtime stable graphics? Answer: because the CH1 and CH2 inputs are two completely irrelevant signals, the phase difference between them is difficult to maintain a constant, so they don't have a long time stable waveform. (3) assume that the input is a sinusoidal signal in the oscilloscope Y axis, horizontal scanning frequency used for 120Hz, there are three stable complete sine wave on the screen, then what is the frequency of the signal? Whether this is a good method for the measurement of the signal frequency? Why? Answer: the frequency of the input signal is 360Hz. This method is not good because the measurement of the signal frequency, frequency accuracy by this method of measuring low. (4) the scanning frequency oscilloscope is far greater than or much less than the frequency of a sinusoidal signal input, the graphics on the screen is what? Answer: the scanning frequency is far less than the frequency of sinusoidal signal input, a graph is dense sine wave; scanning frequency is far higher than the frequency of sinusoidal signal input, the signal waveform of a cycle will be decomposed into several sections, graphic display will become mesh cross line.Experiment seven(1) the current correction table, if it is found that the modified milliammeters readings are always higher than standard gauge readings, the shunt resistance should be adjusted big or small? Why?Answer: should be small. Let the same standard reading meter circuit, which keeps the loop current constant, the shunt resistance value decreased after will receive more current, so that the current flowing through the modified table headermodification decreases, the reading is reduced.(2) correction voltage meter, if it is found that the modification of the voltage meter reading is always lower than the standard gauge readings, pressure resistance should be adjusted in big or small? Why?Answer: should be small. Let the same standard reading meter circuit, which is added in the modified Ammeter voltage constant. Small resistance, total resistance modification table is reduced, through the modified milliammeter increases, which also increased reading.(3) prove that using an ohmmeter measuring resistance, if the head pointer is refers to the scale in the center of the dial, then the ohmmeter indication why is exactly equal to the internal resistance of the ohmmeter value.Answer: a head pointer full scale current is Ig, the head pointer refers to the center of the dial in the circuit when the current is I, according to the problem, when the internal table is Rg, resistance to be measured at Rx; according to the working principle of an ohmmeter, when the measured resistance Rx = 0,. That is, it can be Rx = Rg. So, the ohmmeter displays readings is the internal resistance of the ohmmeter.The principle and application of [eight] experimental oscilloscope1. analog oscilloscope can display the signal of high speed track why change?Answer: in the analog oscilloscope vertical deflection plate plus the observed signal voltage in the horizontal deflection plate plus the sawtooth wave (time linear change) signal voltage, so the tube axis of oscilloscope is equivalent to the Cartesian coordinate time axis, after a period of a sawtooth signal, electron beam at in the screen tube painted on the observed signal waveform of a trajectory. When a periodic sawtooth wave signal is greater than or equal to the cycle signal and its phase locked (synchronous), electron beam in the display screen tube painted on the same trajectory observed signal waveform,Because of the persistence of vision and screen the human eye afterglow, can be observed signal waveform.(2) in this experiment, to observe the pattern of Li Saru, why not long time stable graphics?Answer: because the CH1 and CH2 inputs are two completely irrelevant signals, the phase difference between them is difficult to maintain a constant, so they don't have a long time stable waveform.(3) assume that the input is a sinusoidal signal in the oscilloscope Y axis, horizontal scanning frequency used for 120Hz, there are three stable complete sine wave on the screen, then what is the frequency of the signal? Whether this is a good method for the measurement of the signal frequency? Why?Answer: the frequency of the input signal is 360Hz. This methodis not good because the measurement of the signal frequency, frequency accuracy by this method of measuring low.(4) the scanning frequency oscilloscope is far greater than or much less than the frequency of a sinusoidal signal input, the graphics on the screen is what?Answer: the scanning frequency is far less than the frequency of sinusoidal signal input, a graph is dense sine wave; scanning frequency is far higher than the frequency of sinusoidal signal input, the signal waveform of a cycle will be decomposed into several sections, graphic display will become mesh cross line.。

大学物理实验思考题答案及解析

大学物理实验思考题答案及解析

大学物理实验思考题答案及解析实验四、波器及其应用1.在示波器状况良好的情况下,荧光屏看不见亮点,怎样才能找到亮点?显示的图形不清晰怎么办?首先将亮点旋钮调至适中位置,不宜过大,否则损坏荧光屏,也不宜聚焦。

在示波器面板上关掉扫描信号后(如按下x-y键),调节上下位移键或左右位移键。

调整聚焦旋钮,可使图形更清晰。

2.如果正弦电压信号从Y轴输入示波器,荧光屏上要看到正弦波,却只显示一条铅直或水平直线,应该怎样调节才能显示出正弦波?如果是铅直直线,则试检查x方向是否有信号输入。

如x-y键是否弹出,或者(t/div)扫描速率是否在用。

如果是水平直线,则试检查y方向是否信号输入正常。

如(v/div)衰减器是否打到足够档位。

3.观察正弦波图形时,波形不稳定时如何调节?调节(t/div)扫描速率旋钮及(variable)扫描微调旋钮,以及(trig level)触发电平旋钮。

4.观察李萨如图形时,如果只看到铅直或水平直线的处理方法?因为李萨如图形是由示波器x方向的正弦波信号和y方向的正弦波信号合成。

所以,试检查CH1通道中的(v/div)衰减器旋钮或CH2通道中的(v/div)衰减器旋钮。

5.用示波器测量待测信号电压的峰-峰值时,如何准确从示波器屏幕上读数?在读格数前,应使“垂直微调”旋到CAL处。

建议用上下位移(position)旋钮将正弦波的波峰或波谷对齐某一横格再数格数,就不会两头数格时出现太大的误差。

6.用示波器怎样进行时间(周期)的测量?在读格数前,应使“垂直微调”旋到CAL处。

根据屏幕上x轴坐标刻度,读得一个周期始末两点间得水平距离(多少div),如果t/div档示值为0.5ms/div,则周期=水平距离(div)×0.5ms/div。

7.李萨如图形不稳定怎么办?调节y方向信号的频率使图形稳定。

实验六、霍尔效应(Hall Effect)1、实验过程中导线均接好,开关合上,但Vh无示数,Im和Is示数正常,为什么?(1) Vh组的导线可能接触不良或已断。

大学物理实验报告思考题答案

大学物理实验报告思考题答案

大学物理实验报告思考题答案【篇一:大学物理实验思考题答案及解析】>1.在示波器状况良好的情况下,荧光屏看不见亮点,怎样才能找到亮点?显示的图形不清晰怎么办?首先将亮点旋钮调至适中位置,不宜过大,否则损坏荧光屏,也不宜聚焦。

在示波器面板上关掉扫描信号后(如按下x-y键),调节上下位移键或左右位移键。

调整聚焦旋钮,可使图形更清晰。

2.如果正弦电压信号从y轴输入示波器,荧光屏上要看到正弦波,却只显示一条铅直或水平直线,应该怎样调节才能显示出正弦波?如果是铅直直线,则试检查x方向是否有信号输入。

如x-y键是否弹出,或者(t/div)扫描速率是否在用。

如果是水平直线,则试检查y方向是否信号输入正常。

如(v/div)衰减器是否打到足够档位。

3.观察正弦波图形时,波形不稳定时如何调节?调节(t/div)扫描速率旋钮及(variable)扫描微调旋钮,以及(trig level)触发电平旋钮。

4.观察李萨如图形时,如果只看到铅直或水平直线的处理方法?因为李萨如图形是由示波器x方向的正弦波信号和y方向的正弦波信号合成。

所以,试检查ch1通道中的(v/div)衰减器旋钮或ch2通道中的(v/div)衰减器旋钮。

5.用示波器测量待测信号电压的峰-峰值时,如何准确从示波器屏幕上读数?在读格数前,应使“垂直微调”旋到cal处。

建议用上下位移(position)旋钮将正弦波的波峰或波谷对齐某一横格再数格数,就不会两头数格时出现太大的误差。

6.用示波器怎样进行时间(周期)的测量?7.李萨如图形不稳定怎么办?调节y方向信号的频率使图形稳定。

实验六、霍尔效应(hall effect)1、实验过程中导线均接好,开关合上,但vh无示数,im和is示数正常,为什么?(1) vh组的导线可能接触不良或已断。

仔细检查导线与开关连接以及导线是否完好正常。

(2)vh的开关可能接触不良。

反复扳动开关看是否正常。

(3)可能仪器的显示本身有问题。

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大学物理实验B复习思考题
各位同学注意:
大学物理实验B理论考试在《大学物理》课程期末考试后增加半小时进行,内容由教材P4-P24的绪论课内容(44%)及各实验的相应思考题(56%)构成。

各位同学需复习自己选做的实验部分和上学期的《示波器原理和使用思考题》、《简谐振动的研究》以及《分光计的调整与使用》实验。

答疑方式:
1、所列复习思考题大部分解答可在物理实验中心网站/w3cn3/电子资源目录下的电子教案查找。

2、如在电子教案未能找到答案,可以登入物理实验中心网站的师生交流栏目,注册用户名,在实验问题子栏目下提出问题,老师在一天内给出问题答复。

3、或者需要解答的同学先到每班学习委员或课程课代表处登记问题,由学习委员或课程课代表统一找相应老师答疑。

如还未得到圆满答复再单独找相应老师答疑。

一、绪论课内容提要
(一)测量P4
1、测量的概念
2、★测量的分类(举例圆柱密度测量问题)
(二)误差P5
1、误差的概念
2、误差的定量表示
绝对、相对误差的概念。

物理实验的要求相对误差%.
5
3、误差的分类
(1)系统误差及来源
(2)随机误差
★标准偏差的表示
(三)★不确定度和测量结果的表示(练习题3)P8
1、不确定度概念的理解P8
2、总不确定度的表示(A类分量、B类分量)P9
3、测量结果的三要素P9
(四)★直接和间接测量结果的处理P10
1、直接测量结果
(1)仪器误差:仪器的最小分度值
米尺为最小分度值的二分之一
(2)多次测量结果总不确定度
相对误差的两种表示形式P10(7)和(8)式
(3)单次测量结果总不确定度
(4)例题讲解P10
2、间接测量结果
误差传递公式
(1)函数关系为和差形式
(2)函数关系为积商形式
(3)★结合例题讲解(讲明例题归纳的结论P14)
(五)有效数P14
1、概念
2、★运算规则
(1)加减法则
(2)乘除法则
(3)函数的有效数运算(对数、指数、开方、三角函数等)
(4)中间运算结果的保留
(六)数据处理方法
1、列表法
要求:报告中有多个表格需编号,如表1、表2等,并且表格上方必须写上表格的名称
详见书本列表的基本要求
2、作图法
要求:报告中有多个图需编号,如图1、图2等,并且图下方必须写上图的名称详见书本作图的基本要求
3、逐差法
4、最小二乘法
注:加★的为重点内容。

二、各实验的相应思考题:
分光计的调整与使用
(答疑教师:王悦悦)
1、分光计调整好的标准(P134(1)(2)(3))
2、分光计实验中,什么是各半调节法?叙述具体调节步骤。

(请结合图形说明)
3、简述自准法调节望远镜的方法。

简谐振动的研究
(答疑教师:刘风勤)
1.谐振动实验中,如何调整气垫导轨水平?如何判断其已经水平?
2.焦利氏秤如何应用于测量弹簧的倔强系数K?
3.如何使用智能数字测时器测速度、周期?
示波器原理和使用思考题
(答疑教师:郑军)
1、如果被观测的图形不稳定,出现向左移或向右移的原因是什么?该如何使之稳定?
2、在观察李萨如图形时,能否用示波器的“同步”将其稳定下来?如果不能,那是为
什么?
3、已知f ch1=250 Hz,通过观察李萨如图形,当n ch1:n ch2= 2 : 3 时,求f ch2;并画出图形。

电子荷质比的测定思考题
A I
K G U 2
(答疑教师:倪涌舟)
1、什么是电子荷质比?
2、推导电子荷质比的计算公式。

3、在测量电子束半径时需要哪三点成一线?为什么?
夫兰克—赫兹实验思考题
(答疑教师:刘风勤、汪小刚)
1. 夫兰克-赫兹实验是探索原子结构的重要手段之一,实验中用的是什么方法?
2. 在如下的夫兰克-赫兹实验的原理图中, K G U 2是 电压, A G U 2是
电压。

.
3. 在如下的充氩的夫兰克-赫兹管A I ~K G U 2曲线中,为什么会造成第二次板极电流的下降
(cd 段)?
眼镜蛇研究电容开关现象思考题
(答疑教师:陈亮、郑军)
1.电容充电时间与哪些因素有关?
2.如何理解电容的开关特性?怎样提高电容的开关速度?
用磁阻传感器测量地磁场实验思考题
(答疑教师:陈均朗、张中卫)
1.磁阻传感器的两条铝制电流带中,偏置磁场带的作用与意义是什么?
2.如果在测量地磁场时,在磁阻传感器周围较近处,放一个铁钉,对测量结果将产生什么
影响?
3.为何坡莫合金磁阻传感器遇到较强磁场时,其灵敏度会降低?用什么方法来恢复其原来的灵敏度?
太阳能电池特性测定思考题
(答疑教师:戴朝卿,王悦悦)
1、画出实验内容1所需的电路图。

2、在实验内容1中电流表内接还是外接,为什么?
3、连接电路时,应注意什么?
利用光电效应测定普朗克常数思考题
(答疑教师:陈均朗、张中卫)
1、什么是截止电压?
2、用光电效应测普朗克常数h的基本原理是什么?
3、什么是光电管的伏安特性曲线?
4、定出光电效应方程及其意义。

5、怎样防止光电管不受强光直接照射?
迈克尔逊干涉仪实验思考题
(答疑教师:陈亮、郑军)
1、下列读数哪个是迈克尔逊干涉仪的测量值?。

为什么?
A.、34.32964cm B、34.32964mm C、34.3296mm D、34.329cm
2、测量激光束的波长的操作是,转动粗调手轮,移动反射镜M1, 计数圆条纹的外冒或内陷,若外冒或内陷的圆条纹为N条,则反射镜M1移动距离△d和入射光波长 的关系为。

3、测量时为避免空程误差,必须调节微调鼓轮,使出现现象时才读数。

4、迈克尔逊干涉仪实验中补偿板的作用是什么?
全息照相思考题
(答疑教师:倪涌舟、郑军)
1、全息照相与普通照相有何区别?
2、简述全息照相技术的两步成像方法,各利用了什么原理实现?
3、绘出拍摄全息照片的基本光路,说明拍摄时的技术要求。

4、如果全息干板不小心打碎了,使用其中一小块来再现,问对再现现象有什么影响?试说明理由。

透射式超声成像思考题
(答疑教师:汪小刚、刘风勤)
1、本实验定标的目的是什么?
2、在接收换能器最大值调节过程中,要满足软件读数窗口显示的电压值在范围。

若该电压超出规定的电压范围,则需要适当调节旋钮,使电压读数减小。

3、在开始扫描以后,应该注意什么?。

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