论文部分内容阅读
本刊1992年第10期刊登的“青岛市1992年高三目标教学质量检测物理试题”的第8题,命题不妥,很值得商榷。 [原题] 有界匀强磁场沿水平分布在abcd区域内,在磁场的正上方有金属线框efgh。(如图);当gh边距磁场边界线ab高为H时,释放线框自由落下,线框全部进入磁场的过程中,线框恰好做匀速运动,下列说法中对的是: A.若线框从大于H高处释放,则线框全部进入磁场的过程是先减速可能后做匀速运动。 B.若线框从小于H高处释放,则线框全部进入磁
The 8th title of Qingdao Physics Examination Paper on the Teaching Quality of the Third Year Objectives in 1992 was published in the 10th issue of this magazine. The proposition is not appropriate and it is debatable. [Original title] Bounded homogeneous magnetic field is distributed horizontally in the abcd region, with a metal wireframe efgh directly above the magnetic field. (Figure); When the gh margin of the magnetic field boundary line ab is high H, the release of the wire frame free fall, the wire frame all into the magnetic field, the wire frame just to do uniform movement, the following statement is: A. If When the wireframe is released from a height greater than H, the process of all the wireframes entering the magnetic field is decelerating first and then doing uniform motion. B. If the wireframe is released from a height less than H, the wireframe is all magnetic