利用对称性分析的思想方法,可以在中学阶段现有知识的基础上开拓思路、启迪智慧、培养分析问题和解决问题的能力,激发学习物理的灵感。一、问题及分析众所周知,通电长直导线(导线直径d→0)周围的磁场分布就是以通电直导线为圆心的一系列同心圆,越靠近通电直导线,磁场越强,磁感线分布越密(如图1)。通电长直圆柱体(导体直径即横向线度d为一定尺寸,电流为体分布)周围磁场分 Using the method of symmetry analysis, we can develop ideas, enlighten wisdom, cultivate the ability to analyze and solve problems based on the existing knowledge in secondary school and stimulate the inspiration of learning physics. First, the problem and analysis As we all know, the long-wire power line (wire diameter d → 0) around the magnetic field distribution is straight line energized straight as a series of concentric circles, the closer to the power line, the stronger the magnetic field, the magnetic line distribution Dense (Figure 1). Long straight cylinder power (conductor diameter that is the transverse dimension d is a certain size, the current distribution of the body) around the magnetic field