带电粒子在复合场中的运动既是教学的重点,又是教学的难点.在现行的教学参考书、复习资料中,普遍流行着以下两道选择题,学生普遍感觉到困惑不解.笔者在教学中发现,要清晰地讲明白这两道题并非易事.为此笔者对这两道选择题做了深入的探究,如有不当之处还请各位物理同仁批评指正。 The movement of charged particles in the compound field is not only the focus of teaching but also the difficulty of teaching.In the current teaching reference books and reviewing materials, the following two multiple choice questions are commonly prevalent, and students generally feel puzzled. Found that it is not easy to clearly understand these two questions.To this end I made a thorough exploration of these two multiple-choice questions, if there is any discrepancy, please also criticize and correct the physical colleagues.