试题与答案

在“凸透镜成像的规律”的实验探究中。 (1)让凸透镜正对着太阳,通过透镜的太阳光

题型:实验题

题目:

在“凸透镜成像的规律”的实验探究中。

(1)让凸透镜正对着太阳,通过透镜的太阳光能聚集于一点,测得该点到凸透镜中心的距离是10 cm,则该凸透镜的焦距为______________cm。

(2)如图所示,把蜡烛、凸透镜、光屏依次放在桌面上,点燃蜡烛,使烛焰、凸透镜、光屏的中心大致在同_____________、同一直线上。

(3)某实验小组测得的数据如下表所示。由表中数据分析得知:当物距大于2倍焦距时,凸透镜成倒立、___________的实像。该实像_____________(选填“能”或“不能”)直接用光屏承接。

答案:

(1)10

(2)高度

(3)缩小,能

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题型:单项选择题

Passage Three

A rapid means of long-distance transportation became a necessity for the United States as settlement (新拓居地) spread ever farther westward. The early trains were impractical curiosities, and for a long time the railroad companies met with troublesome mechanical problems. The most serious ones were the construction of rails able to bear the load, and the development of a safe, effective stopping system. Once these were solved, the railroad was established as the best means of land transportation. By 1860 there were thousands of miles of railroads crossing the eastern mountain ranges and reaching westward to the Mississippi. There were also regional southern and western lines.
The high point in railroad building came with the construction of the first transcontinental system. In 1862 Congress authorized two western railroad companies to build lines from Nebraska westward and from California eastward to a meeting point, so as to complete a transcontinental crossing linking the Atlantic seaboard with the Pacific. The Government helped the railroads generously with money and land. Actual work on this project began four years later. The Central Pacific Company, starting from California, used Chinese labor, while the Union Pacific employed crews of Irish laborers. The two groups worked at remarkable speed, each trying to cover a greater distance than the other. In 1869 they met at a place called Promontory in what is now the state of Utah. Many visitors came there for the great occasion. There were joys all over the country, with parades and the ringing of church bells to honor the great achievement.
The railroad was very important in encouraging westward movement. It also helped build up industry and farming by moving raw materials and by distributing products rapidly to distant markets. In linking towns and people to one another it helped unify the United States.

The building of the first transcontinental system ______.

A.relieved the burden of overall railroad system

B.encouraged people to rush for gold in the west

C.attracted many visitors to the construction sites

D.brought about a rapid growth of industry and farming in the west

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