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由于“电与磁”部分在初中阶段的要求不高,故这部分中考题的变化一直不大,都是些简单的常规题,但偶尔也会出现个别省市的考题新颖独特,令人棘手,笔者从中遴选出其中的几道以飨同学们．例1 (南京市)在一根条形磁铁附近平行放置一根与磁铁形状完全相同的棒状物体XY 后,其周围磁场磁感线的分布情况如图1甲所示．将XY两端对调后,磁感线分布情况未发生
As the “electricity and magnetics” part is not required in the junior high school stage, the changes in this part of the examination questions have not been very big. They are some simple and regular questions, but occasionally, the examination questions in individual provinces and cities are novel and unique. The author selected a few of them from the middle school to the students. Example 1 (Nanjing) After placing a bar-shaped object XY with the same shape as a magnet in parallel around a bar magnet, the distribution of the magnetic field lines around the magnetic field is shown in Fig. 1A. After the two ends of XY are reversed, the distribution of magnetic induction lines does not occur