基于电磁感应原理的单摆法测量重力加速度  

A method of measurement of local gravitational acceleration based on single pendulum combined with electromagnetic induction principle

作　　者：魏杰[1] 易家乐 喻慧琴 杨帆 田勇[2] 何小风 里霖 胡晓军[2] WEI Jie;YI Jia-le;YU Hui-qin;YANG Fan;TIAN Yong;HE Xiao-feng;LI Lin;HU Xiao-jun(School of Transportation and Logistics Engineering,Wuhan University of Technology,Wuhan,Hubei 430070,China;School of Science,Wuhan University of Technology,Wuhan,Hubei 430070,China)

机构地区：[1]武汉理工大学交通与物流工程学院,湖北武汉430070 [2]武汉理工大学理学院,湖北武汉430070

出　　处：《大学物理》2022年第5期52-56,共5页College Physics

摘　　要：本文将单摆法与电磁感应原理相结合,用永磁球体作为摆球,并且在其正下方放置多匝线圈.当摆球做简谐运动时,线圈内部磁通量对应地发生周期性变化,从而产生周期性的感应电动势.使用滤波器模块过滤噪声,并利用示波器采集周期性信号.通过判读电动势信号即可准确获取单摆的周期信息.进一步通过改变摆球和线圈之间的相对高度衡量电磁阻尼对于测量的影响,发现测量的周期与相对高度无关,说明电磁阻尼是可以忽略的,这与半定量分析结果是一致的.本文测量的重力加速度实验值与本地参考值有很好的一致性.In this paper, single pendulum method is combined with electromagnetic induction principle in the experiments. A permanent magnetic sphere as the pendulum ball is used and a multiturn coil is placed directly under it. When the pendulum ball moves in simple harmonic motion, magnetic flux in the coil is disturbed and thereby a periodic induced electromotive force is generated. A filter module was used to suppress the noise and the electromotive force signal was collected by an oscilloscope. As a result, the pendulum period could be determined accurately by collecting electromotive force signal. Furthermore, the distance between the coil and pendulum ball was changed in order to evaluate the effect of electromagnetic damping. The measurement was repeated at different distance and the measured period data was found to be independent on the distance configurations. It indicated that electromagnetic damping could be ignored which was in agreement with our semiquantitative analysis. The local gravitational acceleration measured in this paper was good consistent with the reference value.

关 键 词：单摆法 电磁感应 重力加速度 周期 

分 类 号：O4-34[理学—物理]