电磁感应现象是闭合电路中的一部分导体做切割磁感线运动，该电路中产生感应电流的现象。下列四图中，能说明电磁感应现象的是（）。
A.A
B.B
C.C
D.D
参考答案：B
解析：
解析
闭合电路的一部分导体在磁场中做切割磁感线运动时，导体中就会产生电流，该现象就称为电磁感应现象。
A、该电路中有电源，即通电后，磁场中的金属棒会受力运动，故是利用通电导线在磁场中受力的作用的原理工作的，故该选项错误；
B、在该闭合电路中没有电源，当线圈转动时，其恰好切割磁感线运动，于是灯泡中就会有电流通过，故这就是电磁感应现象，即该选项正确；
C、该装置中有电流通过时，磁场中的线圈会转动，故是利用通电导线在磁场中受力的作用的原理工作的，故该选项错误；
D、该实验是著名的奥斯特实验，该实验说明了通电导线周围存在着磁场，故该选项错误。
故正确答案为B。
考点:科学推理
A man was walking along the street when he saw a woman struggle（奋力）with a large box. It was half in and half 1 of her car. He was a helpful man, so he went up to the woman and said, “Let me give you a hand with that box. It looks very 2 . ” “That’s very kind of you,” the woman said. “I’m having a lot of 3 with it. I think it’s stuck（卡住）. ” “Together we’ll soon move it,” the man said. He 4_ into the back seat of the car and took hold of the other end of the box. He said, “I’m ready. ” And he began to_ 5 hard. For several minutes the man and the woman struggled with the box. Soon they were 6 in the face. “Let’s rest for a minute,” the man said. “I’m sorry, but it 7 stuck. ” A few minutes later, the man said, “Let’s try again. Are you ready?” 8 of them took hold of the box again. “One, two, three!” the man said, and they went on with their struggle. At last, when they were very tired, the man said, “You are 9 . It really is stuck. I don’t think there’s any way we can get it out of the car. ” “Get it out of the car!” The woman cried. “I’m trying to get it 10 !”
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