field force line

基本解释

The invisible force field around the magnet becomes suddenly visible when the iron filings fall into line.
磁棒四周無形的力場在鉄屑排列成行時，一下子展現出了它的真麪目。
However, the speed of the rotor rotation speed did not change the high magnetic field, or magnetic line of force will not be able to cut the copper.
不過此轉子轉動速度沒有磁場變換之速度高，否則磁力線將不能爲銅棒所切割。
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Traveling-wave interaction and secondary magnetic field is generated electromagnetic force, which is a straight line to run the basic principles of electric motors.
行波磁場與次級相互作用便産生電磁推力，這就是直線電動機運行的基本原理。
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