【多选题】Fill out the spaces after the record . The answers are bellow , select the best one and fill out the spaces with only letter from A to M. (听录音完成填空,选择合适的单词,填写A-M字母;注意填写答案时,答案前后一定不要留空格或符号,系统自动阅卷,可能会检测有误...
A.
nickel
B.
hundreds
C.
coil
D.
vacuum
E.
classified
F.
nonmagnetic
G.
pass
H.
provides
I.
field
J.
materials K. path L. vocum M.classify An inductor is basically a 1 of wire. The material around which the coil is formed is called the core. Coils are wound on either 2 or magnetic materials. Examples of nonmagnetic 3 are air, wood, copper, plastic, and glass. The permeabilities of these materials are the same as for a 4 . Examples of magnetic materials are iron, 5 , steel, cobalt, or alloys. These materials have permeabilities that are 6 or thousands of times greater than that of a vacuum and are 7 as ferromagnetic. A ferromagnetic core 8 a better 9 for the magnetic lines of force and thus permits a stronger magnetic 10 .