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
Invisibility Ring Scientists can’t yet make an invisibility cloak like the one that Harry Potter uses. But, for the first time,
Invisibility Ring Scientists can’t yet make an invisibility cloak like the one that Harry Potter uses. But, for the first time,
admin
2009-06-15
24
问题
Invisibility Ring
Scientists can’t yet make an invisibility cloak like the one that Harry Potter uses. But, for the first time, they’ve constructed a simple cloaking device that makes itself and something placed inside it invisible to microwaves.
When a person "sees" an object, his or her eye senses many different waves of visible light as they bounce off the object. The eye and brain then work together to organize these sensations and reconstruct the object’s original shape. So, to make an object invisible, scientists have to keep waves from bouncing off it. And they have to make sure the object casts no shadow. Otherwise, the absence of reflected light on one side would give the object away.
Invisibility isn’t possible yet with waves of light that the human eye can see. But it is now possible with microwaves. Like visible light, microwaves are a form of radiant energy. They are part of the electromagnetic spectrum, which also includes radio waves, infrared light, ultraviolet rays, X rays, and gamma rays. The wavelengths of microwaves are shorter than those of radio waves but longer than those of visible light.
The scientists’ new "invisibility device" is the size of a drink coaster and shaped like a ring. The ring is made of a special material with unusual ability. When microwaves strike the ring, very few bounce off it. Instead, they pass through the ring, which bends the waves all the way around until they reach the opposite side. The waves then return to their original paths.
To a detector set up to receive microwaves on the other side of the ring, it looks as if the waves never changed their paths -- as if there were no object in the way ! So, the ring is effectively invisible.
When the researchers put a small copper loop inside the ring, it, too, is nearly invisible. However, the cloaking device and anything inside it do cast a pale shadow. And the device works only for microwaves, not for visible light or any kind of electromagnetic radiation. So, Harry Potter’s invisibility cloak doesn’t have any real competition yet.
选项
A、can now make an invisible cloak of the same kind as he uses.
B、try to make an invisible cloak of the same kind as he uses.
C、try to invent a device similar in idea to the invisible cloak he uses.
D、know that it is possible to make an invisible cloak of the same kind.
答案
C
解析
文章的第一段告诉我们,科学家还没有发明哈里·波特使用的那种隐身衣,所以不能选 A;该段还告诉我们,科学家已制造了一种装置,这种装置能使自身或置于其中的物体不被微波发现,所以C是正确选择,也就是说,科学家发明的隐形装置和哈里波特的隐身衣仅仅在概念上相同,这同时说明B和D是错误的选择。
转载请注明原文地址:https://kaotiyun.com/show/aFhd777K
本试题收录于:
职称英语理工类基础题库职称英语分类
0
职称英语理工类基础
职称英语
相关试题推荐
A"historicallyminded"researcher______.InParagraph1theauthormeanstoillustratethat______.
"Othercountrieshaveaclimate;inEnglandwehaveweather".Thisstatementsuggeststhat______.Theword"lands"inthelast
OnBritishNewspapers1Besidesthedailynewspapers,thereareanumberofSundaynewspapersinBritain.Manyofthemareconn
Thesecondinjectionshouldhavebeengivenoncethefirstdrughadtakeneffect.
TherewerenohumanbeingsontheearthduringtheIceAge.Accordingtothepassage,beforetheIceAgethecontinentalshelf
Accordingtothepassage,someengineersaretryingtoimprovethehandlebarsbecauseInwhichofthefollowingwaysthehandgr
A.Morrison’sSurveyandFindingsB.CommentsonCurrentGuidelinesC.TheRelationofSexuallyTransmittedDiseasestoIUDComp
ChestCompressions:MostImportantofCPRCardiopulmonaryresuscitation,orCPR,cansavethelifeofsomeonewhosehearthasst
LittleLadyStartsBigWarHarrietBeecherStowehadpouredherheartintoheranti-slaverybook"UncleTom’sCabin."(46)Thepu
Scientistsworkingonaproblemdonotknowandsometimescan’tevenguesswhatthefinalresultwillbe.LateonFriday,8Nove
随机试题
关于招标人行为的说法,正确的有()。
所谓伊人,在水一方伊人:
多囊肝与肝内多发性囊肿的主要鉴别点是
下列各项,可引起腹痛伴急性高热、寒战的是
35岁初产妇,停经20周开始发现血压偏高,170~1.50/110~90mmHg,伴下肢水肿,偶有头痛;36周时,血压为180/120mmHg,下肢水肿及头痛、头晕加重,尿蛋白(+),下列何项诊断最恰当
关于冬期桩基施工的说法,正确的有()。
根据下列材料,回答问题。2018年全年批发和零售业增加值84201亿元,比上年增长6.2%;交通运输、仓储和邮政业增加值40550亿元,增长8.1%;住宿和餐饮业增加值16023亿元,增长6.5%;金融业增加值69100亿元,增长4.4%
要建立(),通过治安信息的收集与分析,不断提高对治安危害的预见性,加强超前控制。
阅读下面的材料,回答后面的问题。材料一:在某市一务不足400米长的步行街上,清洁工人清理出人们吐掉的口香糖约15公斤。某市公交公司无人售票公共汽车3年间收到的残币假钞竞高达50万元。一孕妇在参加某事业单位录用考试后上了专门接送考生的大客车,全车考生没有一
根据所给材料,回答下列问题。①两条河汇合到一起,如果河水颜色差异较大,水流交汇处就会形成一条分界线;如果这条分界线看起来非常清晰、而且又绵延很长,那就形成了“泾渭分明”这种风景。此类风景的先决条件是,相汇的两水颜色要有足够差异,通常是一黄一绿,有
最新回复
(
0
)