带电粒子在匀强磁场中的偏转问题一直是高考的一个热点.特别是涉及到动态情景的圆问题更是学生难以理解和解答的一个重点问题.解答这类问题,对学生的解题能力提出了较高的要求,不仅要求学生掌握有关的物理知识与解题技能,更需要学生的较强的空间想象能力和动态思维能力.如何利 The deflection problem of charged particles in uniform magnetic field has been a hot spot in college entrance examination.Especially the circle problem involving the dynamic situation is one of the key problems that students can not understand and answer.To solve these problems, A higher requirement, not only requires students to master the relevant knowledge of physics and problem-solving skills, but also the students need strong spatial imagination and dynamic thinking ability.