A.磁感應(yīng)強(qiáng)度 B.磁通 C.磁場(chǎng)強(qiáng)度 D.磁阻
A.1~40m B.1~10m C.1~20m D.1~50m
A.電壓 B.電流 C.功率 D.頻率