A.電磁感應(yīng) B.電流的磁效應(yīng) C.能量平衡 D.電流的熱效應(yīng)
A.5A B.7A C.10A D.15A
A.匝數(shù)少、電壓低 B.匝數(shù)多、電壓低 C.匝數(shù)少、電壓高 D.線徑小、電壓低