如图所示，表示磁场B、电荷运动方向v和磁场对电荷的作用力F的相

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问题选择题

如图所示，表示磁场B、电荷运动方向v和磁场对电荷的作用力F的相互关系图中正确的是

答案

答案：D

题目分析：根据左手定则：磁感线垂直穿入手心，四指指向正电荷运动方向,大拇指指向洛伦兹力方向,所以D图符合左手定则

故选D

点评：知道在什么条件下用左手定则（判断受力时），知道怎样运用左手定则，注意电荷运动方向、磁场、洛伦兹力的方向关系．

补全对话，情景问答

用适当的句子填写空白处，使对话恢复完整。

Reporter: 1 . You just won the first prize in the state tennis competition.

Micheal: Thank you.

Reporter: Micheal, how old are you?

Micheal: Seven.

Reporter: Seven? 2 .

Micheal: Since I was three.

Reporter: 3 .

Micheal: My father. And I take private lessons, too.

Reporter: 4 .

Micheal: I've taken lessons here for two years.

Reporter: 5 .

Micheal: I play three or four days aweek. But I really want to practise every day.

Reporter: Wish you greater success.

Micheal: Thank you.

选择题

毛毛的爷爷给他讲英雄故事：“他用自己的胸膛堵住敌人正在发射的射孔……”，请猜测这位英雄应该是

[ ]

A．雷锋

B．黄继光

C．邱少云

D．王崇伦