Newton ring experiment is a classical experiment about equal thickness interference．The curvature

radius of a plate-convex lens can be measured using the Newton ring method．One important step in this method

is to transform the formula into a measurable form． It is commonly considered that the reason for this

transformation is that one cannot know the center“or”the order．We will show that both the center“and”the

order cannot be measured．Meanwhile，we also prove that the data can be processed with linear fitting method．

The experimental data of the pull-off method to measure the surface tension coefficient is calculated in detail，and the accuracy of the measurement results is better at room temperature．A single measurement was performed under variable temperature． Due to the low accuracy of the temperature control device of the instrument and the small change of the surface tension coefficient with temperature，the measured value of each temperature point has a certain deviation，but the change trend of the experimental results is basically the same．

In the experimental process of measuring liquid surface tension coefficient by pull-off method，there are many factors that influence the experimental results． Four factors that have significant influence on the experiment are summarized and analyzed by theoretical analysis，namely，the error of surface tension coefficient caused by temperature measurement deviation; Incorrect k value caused by rust or wear of weight leads to error of surface tension coefficient; The surface tension coefficient error is caused by the change of △U caused by the water on the ring，and the surface tension coefficient error is caused by the measurement error of the inner and outer diameters of the ring．The analysis results show that the surface tension coefficient measured by the experiment will gradually decrease with the increase of temperature，and its measurement error will be

aggravated with the increase of the number of rusty weights，the mass of water droplets attached to the ring and

the measurement error of inner and outer diameters．The research results can play a guiding role in reducing the

measurement error of liquid surface tension coefficient by pull-off method in the experimental teaching process

of college physics teaching．

Based on LabVIEW software, the imaging process of Abbe 4F system is designed at all the parts. Object image is generated by two-dimensional grating, and the frequency spectrum is obtained by Fourier transform.  After the frequency spectrum is processed by different filters,  an image plane image is produced by inverse Fourier transform. In the design and simulation of the generated two-dimensional grating and different two-dimensional filters, it is convenient to operate and control the type and size of the grating and the filters. This program plays an active role in understanding the correspondence between frequency spectrum and spatial image.

Based on the Huygens–Fresnel principle, the intensity distribution expression of double-slit interference with the consideration of slits width is derived. According to the expression, the theoretical results are simulated. It is found that, if the width of the slits cannot be neglected, the interference fringes is not the ideal fringes with same intensity and spacing, but the intensity magnitude decreases with the radial distance increases from center. Moreover, if the distance between two slits is integral multiple of the width of each slit, the fringe may disappear. The explanation of the theoretical results is presented. In addition, the experiment is carried out, and experimental observation is consistent with the theoretical simulation. It is a meaningful discussion for further understanding the teaching and experiment of double-slit interference experiment.

The spring elastic coefficient is accurately measured based on the principle of ultrasonic ranging and lever amplification. The device uses an ultrasonic measuring system to accurately measure the expansion length of the spring amplified by the lever principle, and uses the method of pulling the spring up vertically to eliminate the influence of spring gravity on the experiment, so as to accurately determine the deformation and elastic coefficient of the spring. The experimental device is a new device for measuring spring elasticity coefficient accurately. It has the advantages of small measurement error, simple operation and strong intuition. It can be used not only as a device for measuring spring elasticity coefficient accurately, but also as a teaching demonstration device for classroom teaching to stimulate students' interest in physical experiments.

We have established a model for the analysis of azimuthal-radial pendulum by Lagrangian mechanics. We list the I agrangian function of the system and consider the influence of air resistance. The theoretical trajectory of the azimuth-radial pendulum is obtained by numerical simulation.The influence of the weight' s mass , the releasing azimuth angle and the releasing radial angle on the maximum displacement in the direction of azimuth was investigated by using the method of controlling variables.The experimental results were in good agreement with the numerical simulation results , which further proved the correctness of our theory.

The determination of Young's modulus of wire is one of the important experiments in college physics experiment. This experiment comprehensively trains students' basic physical experiment skills, such as measurement, data processing and measurement skills. In this paper, the teaching content has been expanded. For the aspect of the method, the reference ruler is proposed to measure the distance between mirror rulers and the length of wire, which is difficult to accurately measure, so as to improve the measuring accuracy. For the aspect of the content, the research contents of elastic hysteresis property of materials are expanded by the characteristics of stress corresponding to strain when adding or subtracting weights; In terms of data processing, the least square method and item-by-item difference method are adopted to process the data, the young's modulus values obtained are 1.88454×1011 Pa and 1.88959×1011 Pa, respectively. The relative error between them is only 2%.

Based on the GGDC-B type silicon photocell comprehensive experimental instrument,  the basic characteristics of silicon photocells were studied. Through our experiments, it is concluded that as the illumination increases, the output voltage and current of the silicon photocell gradually increase. In a certain range of illumination, as the load resistance increases gradually, the output current is still linear with the illumination. The smaller the resistance of the load, the larger the range in which the output current is linear with the illumination. In the visible range, the sensitivity of a silicon photocell increases with increasing wavelength.

It introduces an experiment of measuring charge-mass ratio of electron by the method of magnetron controlling. It was focus on analyzing the way of processing the experimental data. In addition, it presents the “Midpoint” method of dealing with experiment data systematically, combining the way of the “Half Saturation Current” and the “Intersection”. The charge-mass ratio of electron was about 1.65×10¹¹ C/kg and 1.81×10¹¹ C/kg with relative errors of 6.25% and 2.84% by using the method of half saturation current and intersection method, respectively. However, the charge-mass ratio of electron was about 1.74×10¹¹ C/kg with relative errors of 1.14% by using the method of “midpoint”. It can be found that the method of “midpoint” can obtain charge-mass ratio of electron with higher precision compared with the method of “Half Saturation Current” and “Intersection”.