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问题 填空题

在做凸透镜成像实验的时候，如果小明将蜡烛放在离凸透镜12cm的

地方，在离凸透镜24cm的另一侧光屏上能得到一个清晰地像，他得到

这个像一定是一个倒立、_________的实像（填“放大、缩小”）。若

烛焰在光屏上所成的像如图2-6所示，为使像清晰地呈现在光屏中央，

应将凸透镜向______移动。（填“上、下”）

答案

放大   上

凸透镜成像规律如下表

物距u与焦距f的关系 像距v与焦距f的关系 像的性质物、像与透镜的位置关系应用
正立/倒立放大/缩小实像/虚像同侧/异侧
u－∞v=f缩小成亮点----测焦距
u＞2ff＜v＜2f倒立   缩小 实像  异侧照像机
u＝2fv＝2f倒立   等大 实像  异侧 
f＜u＜2fv＞2f倒立   放大 实像  异侧投影仪
u＝f不能成像，是一束平行光　　　　　　　　　　　　　　　　　
u＜fv>u正立  放大 虚像  同侧放大镜
 

题中，v>u，因此满足f＜u＜2f，v＞2f，故成倒立、放大的实像；

因为成倒立的像，透镜移动的方向和像移动的方向相反，而题中像像下面移动才能到光屏中央，因此透镜上移。

单项选择题

Cooperation is the common endeavor of two or more people to perform a task or reach a jointly cherished goal. Like competition and conflict, there are different forms of cooperation, based on group organization and attitudes.In the first form, known as primary cooperation, group and individual unite. The group contains nearly all of each individual’’s life. The rewards of the group’’s work are shared with each member. There is an interlocking identity of individual, group, and task performed. Means and goals become one, for cooperation itself is valued.While primary cooperation is most often characteristic of preliterate societies, secondary cooperation is characteristic of many modern societies. In secondary cooperation, individuals devote only part of their lives to the group. Cooperation itself is not a value. Most members of the group feel loyalty, but the welfare of the group is not the first consideration. Members perform tasks so that they can separately enjoy the fruits of their cooperation in the form of salary, prestige, or power. Business offices and professional athletic teams are examples of secondary cooperation.In the third type, called tertiary cooperation or accommodation, latent conflict underlies the shared work. The attitudes of the cooperating parties are purely opportunistic; the organization is loose and fragile. Accommodation involves common means to achieve antagonistic goals; it breaks down when the common means cease to aid each party in reaching its goals. This is not, strictly speaking, cooperation at all, and hence the somewhat contradictory term antagonistic cooperation is sometimes used for this relationship.

As used throughout the passage, the term "common" is closest in meaning to which of the following

A．Ordinary.

B．Shared.

C．Simple.

D．Popular.
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单项选择题

毛 * * 在（）文章中首先提出探索适合中国国情的建设社会主义的任务。

A.《论人民民主专政》

B.《论十大关系》

C.《矛盾论》

D.《实践论》
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