有界磁场是指只在局部空间存在着匀强磁场,带电粒子从磁场区域外垂直磁场方向射入磁场区域,在磁场区域内经历一段匀速圆周运动后射出磁场.有界磁场的边界有的是矩形,有的有两个平行边界,也有的只有一个边界,还有的是圆形边界.这类题能够在考查洛仑兹力知识的同时,考查学生的综 Bounded magnetic field means that there is a uniform magnetic field only in the local space. The charged particles are injected into the magnetic field from the direction of the vertical magnetic field outside the magnetic field. After a section of uniform circular motion in the magnetic field, the magnetic field is emitted. The boundary of the bounded magnetic field is rectangular, Some have two parallel borders, some have only one border, and others have circular borders. Such questions can examine the students’ comprehensive knowledge while examining the Lorentz force knowledge.