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A Guide to the Library’s Facilities To use or reserve the facilities of the library, follow the procedures given at the circulation desk. Group Study Rooms (2F) Students and teaching staff can use these rooms for group study. Students are advised to use unlocked rooms (3 rooms for 2 people, 2 rooms for 4 people) available for free. When you use locked rooms (2 rooms for 4 people, 1 room for 10 people), you need to go through reservation procedures at the circulation desk. These rooms are available for group discussion. Individual Reading Rooms (1-3F) There are 4 single rooms availa在研究产生感应电流条件的实验中，如图1所示，把条形磁铁插入或者拔出闭合线圈的过程，线圈的面积尽管没有变化，但是线圈内的磁场强弱发生了变化，此时闭合线圈中______感应电流（填“有”或“无”）．继续做如图2所示的实验，当导体棒做切割磁感线运动时，尽管磁场的强弱没有变化，但是闭合回路的面积发生了变化，此时回路中______感应电流（填“有”或“无”）．因为不管是磁场强弱发生变化，还是回路面积发生变化，都是穿过线圈所围面积的磁通量发生了变化．这种观察总结的方法是物理学中重要的研究方法，即归纳法．