小明用如图所示的装置探究电磁铁的磁力大小与哪些因素有关，实验记录如表：                                                                                                                                                                                                                                      

电磁铁(线圈匝数)	100圈			50圈
实验次数	1	2	3	4	5	6
电流/A	0.6	1.2	1.5	0.8	1.0	1.5
吸引回形针的数量	7	11	14	5	8	10