electromotive force (emf)

例句：

1. 1. The electric motor is poweredby the electromotive force of thebattery.
   电动机由电池的电动势供电。
2. 2.The scientist used an electromotive forceto generate electricity.
   科学家利用一个电动势来产生电力。
3. 3. The device measures the electromotive force between two points in acircuit.
   该设备测量电路中两点之间的电动势。