一、问题的提出一个无铁芯的自感线圈 ,自感系数为 L ,现将该线圈稍拉伸一些后 ,若不再恢复原形 ,那么它的自感系数将 [　　 ]A.增大　　　　B.减小C.不变　 D.无法确定对此题的答案选法颇多 .有选 A的 ,理由是由于线圈的粗细不变 ,匝数不变 ,长度增大 ,因为长度越长 ,自感系数 First, the problem is proposed a coreless self-inductance coil, self-inductance coefficient is L, now after the coil is slightly stretched, if it does not restore the original shape, then its self-inductance coefficient will increase [A] B. Reduce the C. Invariant D. Can not determine the answer to this question quite a lot of choice. There are election A, reason is because the coil thickness is unchanged, the number of turns the same, the length increases, because the longer the length, since Influencing coefficient