题干

(2011年宁波效实中学检测)图中电感线圈L的直流电阻为RL,小灯泡的电阻为R,小量程电流表G1、G2的内阻不计.当开关S闭合且稳定后,电流表G1、G2的指针均偏向右侧(电流表的零刻度在表盘的中央),则当开关S断开时,下列说法中正确的是(  )

A:G1、G2的指针都立即回到零点

B:G1缓慢回到零点,G2立即左偏,然后缓慢回到零点

C:G1立即回到零点,G2缓慢回到零点

D:G2立即回到零点,G1缓慢回到零点

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答案(点此获取答案解析)

B

同类题3

根据短文内容, 从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

    Let children learn to judge their work.____.If corrected too much,he will stop talking.

    He notices a thousand times a day the difference between the language he uses and the language those around him use.Bit by bit,he makes the necessary changes to make his language like other people's.____.They learn to do without being taught to walk,run,climb,whistle,ride a bicycle.They compare their own performances with those of more skilled people,and slowly make the needed changes.

    But in school we never give a child a chance to find out his mistakes and correct them for himself.We do it all for him.____.Let him work out,with the help of other children if he wants,what this word says,what the answer is to that problem,and whether this is a good way of saying or doing this or not.

    If it is a matter of right answer,as it may be in mathematics or science,give him the answer book.____.Why should we teachers waste time on such routine work?____.Let the children learn what all educated people must some day learn,how to measure their own understanding,and how to know what they know or do not know.

A.Children learn to do all the other things in the same way.

B.Let him correct his own papers.

C.Point out his mistakes.

D.We act as if we thought that he would never notice a mistake unless it was pointed out to him,or correct it unless he was made to.

E.We allow him to learn from other children.

F.A child learning to talk does not learn by being corrected all the time.

G.Our job should be to help the child when he tells us that he can't find the way to get the right answer.