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Magnetic Forces and Fields

Magnetic Poles and Everyday Uses

Description

Magnetism appears in many everyday objects, from toys and hangers to elevators, doorbells, and computer devices. Magnets have two poles, called north and south. Like poles repel each other, while unlike poles attract. Both poles can also attract unmagnetized iron. A single magnetic pole cannot be isolated, because every part...

Transcript

磁现象最早于2500多年前在古代城市马格尼西亚附近被发现。

磁铁常见于扬声器、信用卡、指南针和存储设备等日常物品中。

条形磁铁具有北极和南极。当未磁化的铁钉与其接触时,铁钉会被磁化。

磁体的同名磁极相互排斥,而异名磁极相互吸引。

无法通过将磁体断裂成两部分来分离其磁极。相反,得到的是两个较小的磁体,每个磁体都具有北极和南极。因此,磁单极子从未被观测到。

在导航罗盘中,指针是一根在中心位置悬浮的细长条形磁铁。

指南针的北极被吸引至地球地理北极附近。

地球也像一块巨大的条形磁铁,其磁南极靠近地理北极,而磁北极靠近地理南极。

地球磁轴与地理轴并不重合。这种偏差称为磁偏角。

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