首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
A summary of the physical and chemical nature of life must begin; not on the Earth, but in the Sun; in fact, at the Sun’s very c
A summary of the physical and chemical nature of life must begin; not on the Earth, but in the Sun; in fact, at the Sun’s very c
admin
2010-04-28
51
问题
A summary of the physical and chemical nature of life must begin; not on the Earth, but in the Sun; in fact, at the Sun’s very center. It’s here that is to be found the source of the energy that the Sun constantly pours out into space as light and heat. This energy is liberated at the center of the San us billions upon billions of nuclei hydrogen atoms collide with each other and fuse together to form nuclei of helium, and, in doing so, release some of the energy that is stored in the nuclei of atoms. The output of light and heat of the Sun requires that some 600 million tons of hydrogen be converted into helium in the Sun every second. This the Sun has been doing for several thousands of millions of years.
The nuclear energy is released at the Sun’s center as high - energy gamma radiation, a form of electro- magnetic radiation like light and radio waves only of very much shorter wavelength. This gamma radiation is absorbed by atoms inside the Sun, to be reemitted at slightly longer wavelengths. This radiation, in its turn, is absorbed and reemitted. At the energy filters through the layers of the solar interior, it passes through the X- ray part of the spectrum, eventually becoming light. At this stage, it has reached what we call the solar surface, and can escape into space, without being absorbed Farther by solar atoms. A very small fraction of the Sun’s light and heat is emitted in such directions that, after passing unhindered through interplanetary space, it hits the Earth.
A simple magnifying glass, focusing the Sun’s rays, can scoarch, a piece of wood or set a scrap of paper on fire. Solar radiation can also be concentrated on a much larger scale. It can burn a hole through thick steel plate, for example, or simulate the thermal shock of a nuclear blast. It can, that is, with the help of a super reflector of the sort that has been set up by French scientists high in the Pyroness. The world’s largest solar furnace is a complex of nearly 20,000 mirrors. It can concentrate enough sunlight to create’temperatures in excess of 6000 degrees Fahrenheit.
The furnace’s appearance is as spectacular as its power. Its glittering eight - story - high reflector towers over very old houses. Anchored against a concrete office and laboratory building, the huge reflector consists of nearly 9000 separate mirrors. For the furnace to operate, these small mirrors must be adjusted so that their light will meet exactly at a focal point 59 feet in front of the giant reflector.
Which sentence proves that setting the giant reflector is a delicate operation?
选项
A、The first sentence in the last paragraph.
B、The second sentence in the last paragraph.
C、The last sentence in the last paragraph.
D、The last sentence in the third paragraph.
答案
C
解析
这个问题涉及到两个方面即组成这个装置需要很多镜面而且它们放置的角度必须合适,使它们的光线能在这个巨大的反射装置前59英尺汇聚成一点。相比较而言,后者对整个装置的运转是非常关键的。而且最后一句话提到一个目的状语“For the furnace to operate”,因此应选择C。
转载请注明原文地址:https://kaotiyun.com/show/bMqO777K
0
专业英语八级
相关试题推荐
PresidentBushonWednesdayissuedhissecondvetoofameasureliftinghisrestrictionsonhumanembryonicstemcellexperiment
A、Propershops,evenforeign,shouldbeallowedintheForbiddenCity.B、ThecoffeeshopsdoharmtotheForbiddenCity,sowes
A、AchildshouldbejudgedonhisIQscores.B、Achildshouldbejudgedonhisindividualgifts.C、Achildshouldbejudgedbyh
A、BillGatesisrichbecausehedidn’tfinishhisundergraduatestudy.B、BillGatestellsusthatinordertobecomerich,onem
Thefreedomtoleaddifferenttypesoflifeisreflectedintheperson’scapacityset.Thecapacityofapersondependsonavar
Psychologistshavemanytheoriestoexplainhowwerememberinformation.The【C1】______isthatmemoryworksasakindofstorage
Whatmakesanartistgreat?Brilliantcomposition,nodoubt.Superbdraughtsmanship,certainly.Originalityofsubjectorofcon
It’snevereasytoplumbthereadinghabitsofchildren,butteachersandparentsperenniallyknockthemselvesoutwithworryov
很多人说,美国也许在反恐战争中取得了有形的胜利,但却在信息战中吃了败仗。你同意这种说法吗?
Whichofthefollowingwordscontainsoneboundmorpheme?
随机试题
以杨亿为代表的西昆体的创作特色是()
关于丹毒的临床表现,下列哪项是错误的______。
A.丙戊酸钠B.卡马西平C.乙琥胺D.苯妥英钠E.苯巴比妥特发性失神发作首选
IPV6采用的IP地址为()位地址。
采用商谈的办法获取项目团队成员时,通常可以()。
下列水泵性能参数中,用来确定水泵安装高程的是()。[2012年10月真题]
哈尔滨市某机场新建一片大型生活区(当地冰冻线为-0.6m),从东向西依次布置8栋建筑,均为钢筋混凝土结构,一级耐火等级。各建筑及其水灭火系统的工程设计参数见下表。生活区北侧的城市道路上设置了两个消防水鹤,生活区由两根DN350的市政给水干管,直
某外商投资企业接收捐赠不需要安装的设备一台,确定的入账价值为500000元,设备交付生产车间使用,该企业适用的所得税税率为33%。则在接受捐赠时,应编制的会计分录为()
()是理财师以客户为中心的经营、服务的第一步和最为关键的一步。
Myparents’househadanattic,thedarkestandstrangestpartofthebuilding,reach-ableonlybyplacingastepladderbeneath
最新回复
(
0
)