带电粒子在磁场中的运动问题是高中物理的一个难点,也是高考的热点。在历年的高考试题中几乎都有这方面的考题。带电粒子在磁场中的运动问题,综合性较强,解这类问题既要用到物理中的洛仑兹力、圆周运动的知识,又要用到数学中平面几何中的圆及解析几何知识。对于此类问题,我们一定要小心细致,稍不留神就会犯错,下面我们以一道例题说明此类问题。 The movement of charged particles in the magnetic field is a difficult high school physics, but also hot entrance. In the calendar year college entrance examination questions almost all have questions in this area. The movement problem of charged particles in the magnetic field is more comprehensive. Solving such problems not only needs to use the Lorentz force in physics, the knowledge of circular motion, but also the circle in plane geometry and analytic geometry in mathematics . We must be careful about such issues and make mistakes when we are not at ease. Let us illustrate this issue with a sample of examples.