带电粒子在复合场中运动问题是高考中电磁学部分的重点.要解决这类问题,就应注意带电粒子在复合场中所受洛仑兹力的特点:①洛仑兹力总是跟磁场方向垂直;②洛仑兹力始终与带电粒子的运动方向垂直;⑧洛仑兹力不会对运动的带电粒子做功,即洛仑兹力只能改 The problem of the charged particles in the complex field is the focus of the electromagnetism part of the college entrance examination. To solve this kind of problem, we should pay attention to the characteristics of the Lorentz force that the charged particles receive in the composite field: 1 The Lorentz force always follows the magnetic field. The direction is vertical; 2 Lorentz force is always perpendicular to the direction of motion of the charged particles; 8 Lorentz force does not work on the moving charged particles, that Lorentz force can only change