magnetic effect of electric current

例句：

1. 1. The magnet attracts iron filings to its north pole.
   磁铁吸引铁屑到它的北极。
2. 2. Magnetic fields can be used to detect hidden objects.
   磁场可以用来探测隐藏物体。
3. 3. The scientist discovered a new type of magnet that could change the way we think about matter.
   科学家发现了一种新型磁铁，改变了我们对物质的看法。