本题目来源于试卷: Physics Unit20: Magnetism,类别为 通用国际物理
[单选题]
What fundamental fact /jd+ wzu5:u5wt7m tms x5x he;6+eahx underlies the operation of essentially all electric motors?e h e5x+xxha;6
A. Opposite electric charges attract and like charges repel.
B. A current-carrying conductor placed perpendicular to a magnetic field will experience a force.
C. Alternating current and direct current are both capable of doing work.
D. Iron is the only element that is magnetic.
E. A magnetic north pole carries a positive electric charge, and a magnetic south pole carries a negative electric charge.
参考答案: B
本题详细解析:
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