1. a metal rod or bar wrapped in a wire coil that turns into a strong magnet for as
1.名詞B2
釋義
電磁鐵
通電後才產生磁力的裝置
a metal rod or bar wrapped in a wire coil that turns into a strong magnet for as long as an electric current runs through the coil — widely used in cranes, loudspeakers, and MRI scanners.
例句
Mei-Lin built a simple electromagnet from a battery and nail to pick up paper clips.
Mei-Lin 用一顆電池和一隻鐵釘做了一個簡單的電磁鐵，用來吸起迴紋針。
simple electromagnet made from a nail and battery
The scrap yard crane used a giant electromagnet to lift old cars onto a truck.
廢車場的起重機用一個巨大的電磁鐵把舊車吊到卡車上。
giant electromagnet — real-world use (scrap yard crane)
Inside an MRI scanner, a powerful electromagnet creates a magnetic field around the patient.
在 MRI 掃描儀內部，一個強力電磁鐵在患者周圍產生磁場。
medical use: electromagnet + creates + magnetic field
Unlike a permanent magnet, an electromagnet can be turned on and off by current.
a magnet that retains its magnetic field without needing electricity, such as a bar magnet or fridge magnet
文法句型
electromagnet + verb (is / becomes / attracts)
an electromagnet of + noun
用法筆記
The magnetic force disappears the instant the current stops, making electromagnets useful for lifting and releasing metal objects without physical effort.
常見錯誤
An electromagnet is a natural magnet that always attracts iron.
An electromagnet only becomes magnetic when an electric current flows through it.
Electromagnets are temporary, not natural or permanent.