在相同的时间内,关于一束波长为λ的单色光在空气中和在玻璃中所传播的路程和走过的光程,

题型:单项选择题

问题:

在相同的时间内,关于一束波长为λ的单色光在空气中和在玻璃中所传播的路程和走过的光程,下列叙述中哪个正确?()

A.传播的路程相等,走过的光程相等

B.传播的路程相等,走过的光程不相等

C.传播的路程不相等,走过的光程相等

D.传播的路程不相等,走过的光程不相等

考点:水利水电工程第二章普通物理第二章普通物理题库
题型:单项选择题

Questions 6-10 are based on the following passage.
Dreams have always held a universal fascination. Some primitive societies believe that the soul leaves the body and visits the scene of the dream. Generally, however, dreams are accepted to be illusions, having much in common with day dreams—the fantasies of our waking life. When dreaming, however, one tends to believe fully in the reality of the dream world, however inconsistent, illogical and odd it may be.
Although most dreams apparently happen spontaneously, dream activity maybe provoked by external influences. "Suffocation" dreams are connected with the breathing difficulties of a heavy cold, for instance. Internal disorders such as indigestion can cause vivid dreams, and dreams of racing fire-engines may be caused by the ringing of an alarm bell.
Experiments have been carried out to investigate the connection between deliberately inflicted pain and dreaming. For example, a sleeper pricked with a pin perhaps dreams of fighing a battle and receiving a severe sword wounD.Although the dream is stimulated by the physical discomfort, the actual events of the dream depend on the associations of the discomfort in the mind of the sleeper.
A dreamer’s eyes often move rapidly from side to side. Since people born blind do not dream visually and do not manifest this eye activity, it is thought that the dreamer may be scanning the scene depicted in his dream. A certain amount of dreaming seems to be a human requirement-if a sleeper is roused every time his eyes begin to move fast, effectively depriving him of his dreams, he will make more eye movements the following night.
People differ greatly in their claims to dreaming. Some say they dream every night, others only very occasionally, individual differences probably exist, but some people immediately forget dreams and others have good recall.
Superstition and magical practices thrive on the supposed power of dreams to foretell the future. Instances of dreams which have later turned out to be prophetic have often been recorded, some by men of the highest intellectual integrity. Although it is better to keep an open mind on the subject, it is true that the alleged power of dreams to predict future events still remains unproveD.
Everyone knows that a sleeping dog often behaves as though he were dreaming, but it is impossible to tell what his whines and twitches really mean. By analogy with human experience, however, it is reasonable to suppose that at least the higher animals are capable of dreaming.
Of the many theories of dreams, Freud’s is probably the best known. According to Freud, we revert in our dreams to the modes of thought characteristic of early childhooD.Our thinking becomes concrete, pictorial and non-logic, and expresses ideas and wishes we are no longer conscious of. Dreams are absurd and unaccountable because out conscious mind, not willing to acknowledge our subconscious ideas, disguises them. Some of Freud’s interpretations are extremely fanciful, but there is almost certainly some truth in his view that dreams express the subconscious minD.

Which of the following may most adequately sum up the ideas of the third paragraph

A.Science and dream sequence.

B.How pain may affect dreams.

C.How the mind conditions dreams.

D.The discomfort in the mind of the sleeper in relation with the dream.

题型:单项选择题

未来学家尼葛洛庞蒂说“预测未来的最好方法就是把它创造出来” 。 这给我们的哲学启示是

A.认识总是滞后于实践

B.实践是认识的来源

C.实践是检验认识正确与否的唯一标准

D.实践与认识是合二为一的

题型:单项选择题

根据《股票发行与交易管理条例》的规定,下列事项中上市公司无需作为重大事件公布的是( )。

A.公司订立重要合同,该合同可能对公司经营成果和财务状况产生显著影响

B.公司未能归还到期重大债务

C.20%以上的董事发生变动

D.公司的经营项目发生重大变化

题型:单项选择题

企业机械管理部门组织每年对各施工现场进行的施工机械大检查活动,可提高企业机械管理水平。施工机械大检查的主要内容包括有()。

A.油料和备品配件管理和消耗情况

B.停滞机械的封存、保管情况

C.机械台账、各种报表、运行记录、检查记录、整改记录、保养维修记录、交接班记录等基础资料情况

D.机械操作证、各种机械人员的资格证持证上岗情况

题型:单项选择题

材料1 现代考古证实,玉米起源于一种生长在5000多年前,墨西哥米切肯洲巴尔萨河流域的野生黍类,这种黍类变异性较强,经过墨西哥人数千年的培养,成为今天拥有数百个品种的玉米。大约在16世纪中期,中国开始引进玉米,中国的玉米栽培面积和总产量均居世界第2位。
材料2 2004年2月,玉米育种、栽培专家李登海的“高产玉米新品种‘掖单13号’的选育和推广”荣获国家科技进步一等奖。该品种在较高密度下提高了单株生产力,创造并保持着夏玉米单产1096.29千克的世界纪录。
根据以上材料回答下列问题:

“紧凑型”玉米(叶片夹角小)克服了“平展型”玉米植株间互相挡阳光的缺点,在新品种增产方面起了很大的作用。“紧凑型”有利于增产的原因是______。
除此之外,还有什么措施可以提高光合作用效率请你指出两点:①______;②______。

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