原题如图1所示,空间存在方向垂直于纸面xOy平面)向里的磁场。在x≥0区域,磁感应强度的大小为B。;x<0区域,磁感应强度的大小为λB_0(常数λ<1)。一质量为m、电荷量为q(q>O)的带电粒子以速度υ_0从坐标原点O沿x轴正向射入磁场,此时开始计时,当粒子的速度方向再次沿x轴正向时,求(不计重力):(1)粒子运动的时间;(2)粒子与O点间的距离。一、试题分析本题符合考纲Ⅱ级水平要求,命题突出知识基 The original title shown in Figure 1, the direction of existence of the space perpendicular to the plane xOy plane) to the magnetic field. In the region of x≥0, the magnitude of magnetic induction is B. ; x <0 area, the magnitude of magnetic induction is λB_0 (constant λ <1). A charged particle with mass m and charge q (q> 0) is injected into the magnetic field along the x-axis at a velocity of υ_0 in the positive direction along the x-axis. At this time, the time counting starts. When the particle velocity direction is positive along the x-axis , Seeking (regardless of gravity): (1) the particle movement time; (2) the distance between the particle and the O point. First, the analysis of test questions This question meets the requirements of the test grade Ⅱ level, proposition prominent knowledge base