带电粒子在不计重力的情况下,垂直进入匀强磁场,将在洛仑兹力的作用下做圆周运动.若磁场为有界磁场(直线边界或圆形边界等),粒子将做部分圆周运动.我们在解决这部分问题时,常常要用到物理的知识(半径公式qvB=mv~2/R即R=mv/qB,周期公式T=2πm/qB),更重要的是还要用到数学的几何知识,因此成为同学们复习备考的难点.要想攻克这一难 Charged particles in the absence of any gravity, the vertical into the uniform magnetic field, the Lorentz force will do a circular motion.If the magnetic field is a bounding magnetic field (linear boundary or circular boundary, etc.), the particle will do part of the circular motion When we solve this part of the problem, we often need to use the physical knowledge (radius formula qvB = mv ~ 2 / R or R = mv / qB, the periodic formula T = 2πm / qB) and, more importantly, Mathematical knowledge of mathematics, and therefore become a difficulty for students to review preparation. To overcome this difficulty