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An electromagnet is a piece of metal, usually with wire wrapped around it, that acts like a magnet only while electricity is flowing through the wire. Switch the current on, and it can pull iron or steel; switch it off, and the pull stops. That on-and-off trick is the whole point: cranes in scrapyards, , and many electric motors use it. A fridge magnet stays magnetic by itself; this one does not. It is a school-science and engineering word, but the object itself is ordinary once you know the name. Though actually, a little magnetism can after you cut the power, especially in some metals, but the working idea is still “magnetic when the current is on.”
電磁鐵
組成electro- (electricity) + magnet (a thing that pulls iron).
同家族的字
- magnetthe second half of the word; a magnet that does not need a current
- electromagneticthe adjective for things that involve both electricity and magnetism
- electromagnetismthe science of how electricity and magnetism work together
原始詞典資料1 筆記錄
以下是外部詞典記錄的用法，原文照列，我們還沒有寫成教學內容。上面的說明才是我們自己寫的；有些用法可能上面已經講過了。
electromagnetnoun
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A magnet which attracts metals only when electrically activated.
- Hold the electromagnet near something made of iron and push the switch (S2). […] Large electromagnets are used to move things around at factories and junkyards.
資料來源：英文維基詞典 English Wiktionary（CC BY-SA 4.0）。 原文照列，未經改寫。