Which of the following statements about hard and soft iron in relation to magnetism is correct?
选项:
A:Both hard and soft hard iron are of a permanent nature
B:Hard iron is of a non-permanent nature and soft iron is of a permanent nature
C:Hard iron magnetism is of a permanent nature and soft iron is of a non-permanent nature
D:Both hard and soft iron are of a non-permanent nature
发布时间:2024-05-10 15:23:48