A.220W B.100W C.50W D.25W
A.衡量磁場力做功本領(lǐng)大小 B.衡量非電場力做功本領(lǐng)大小 C.徇電場力做功本領(lǐng)大小 D.具有相對性
A.5庫侖 B.1庫侖 C.4庫侖 D.0.25庫侖