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
Electromagnetic Energy 1 White light seems to be a combination of all colors. The energy that comes from a source of light i
Electromagnetic Energy 1 White light seems to be a combination of all colors. The energy that comes from a source of light i
admin
2014-05-13
55
问题
Electromagnetic Energy
1 White light seems to be a combination of all colors. The energy that comes from a source of light is not limited to the kind of energy you can see. Heat is given off by a flame or an electric light. On a cloudy day it is possible to get a sunburn even though you feel cool. Visible light and the kinds of energy that produce warmth and sunburn are examples of electromagnetic energy.
2 The sun is 93 million miles from the earth. Yet we can use energy from the sun because electromagnetic energy travels through space.
3 Many other kinds of energy are also types of electromagnetic energy. Radio, television, and radar signals travel from transmitters to receivers as low-energy electromagnetic waves. Infrared(红外线的)radiation is an electromagnetic wave. When it is absorbed by matter, heat is produced. Waves of infrared and visible light have more energy than waves of radio, television, or radar. Ultraviolet rays(紫外线)and X-rays are electromagnetic waves with even greater amounts of energy. Infrared radiation is used in cooking food and heating buildings. Sunlight and electric lights are part of our requirements for normal living. Ultraviolet radiation is useful in killing certain disease organisms. X-rays and gamma rays have so much energy that they travel through solid objects. They can be used to detect and treat cancer. X-rays are used in industry to find hidden cracks in metal, and in medicine to reveal broken bones.
4 Usually we use electricity to generate electromagnetic energy. The source of most of our energy is the sun. Heat from the sun causes water to evaporate. When the water falls to the earth as rain, some of it is trapped behind dams and then used to operate electric generators. Other generators are powered by coal, but the energy stored in coal came from the sun, too.
5 Until recently, the source of the tremendous amount of energy given off by the sun was a puzzle. If the sun depended on chemical reactions, it would have used up all its energy long ago. Experiments with electromagnetic radiation led to the theory that mass can be converted into energy. About forty years after the theory was proposed, nuclear energy was harnessed(利用)by man. Chemical energy comes from electron(电子)rearrangement. Nuclear energy comes from a change in the nucleus of an atom. Compared with chemical reactions, nuclear reactions release millions of times more energy per pound of fuel. We now believe that the sun’ s energy comes from the nuclear reactions in which hydrogen is changed into helium(氦).
6 Nuclear energy is beginning to compete with coal as an economical source of power to generate electricity. It is also being used to operate engines in large ships. Scientists continue to seek new and better methods of obtaining and using energy.
A. Nuclear Reactions as the Uasting Source of the Sun s Energy
B. The Most Important Source of Energy
C. Types of Electromagnetic Energy
D. The Machines Used for Energy Generation
E. Seeking New Sources of Energy
F. The Use of Ultraviolet Radiation in Medicine
Paragraph 6
选项
答案
E
解析
通读文章可知,第六段的最后一句是主题句。这句话的大意是:科学家正继续在寻找更好的新方法来获取并使用能源。几个选项中只有E项与之契合,因此选择E项。
转载请注明原文地址:https://kaotiyun.com/show/AOQd777K
本试题收录于:
职称英语理工类B级题库职称英语分类
0
职称英语理工类B级
职称英语
相关试题推荐
Inprevioustimes,whenfreshmeatwasinadequate,pigeonswerekeptbymanyhouseholdsasasourceoffood.
GlucosecannotbeturnedintoenergyinthebodyWithdiabeticretinopathy,thedamagedbloodvesselsintheretina
Accordingtothepassage,apersonsufferingfromcancerwillAccordingtotheNewYorkTimes’report,acombinationoftwonew
15.Themostpressingproblemanyeconomicsystemfacesishowtouseitsscarceresources.
DebateovertheUseofRenewableEnergyAmusableofRockefellerUniversityinNewYork,USsaysthekeyrenewable(可再生的)ene
DebateovertheUseofRenewableEnergyAmusableofRockefellerUniversityinNewYork,USsaysthekeyrenewable(可再生的)ene
DebateovertheUseofRenewableEnergyAmusableofRockefellerUniversityinNewYork,USsaysthekeyrenewable(可再生的)ene
DebateovertheUseofRenewableEnergyAmusableofRockefellerUniversityinNewYork,USsaysthekeyrenewable(可再生的)ene
随机试题
代谢性酸中毒临床上最突出的症状是
抵抗力最强的细菌结构是
对采取保证担保方式的个人汽车贷款,银行贷前调查的内容包括()。
我国和世界上一些国家和地区采用保护价格支持农产品生产,稳定农民收入。下列关于保护价格的说法中,错误的是()。
属于新东北三宝的有()。
学习动机与学习效果之间是一致关系。
西方戏剧起源于()。
______isoftenthecasewithanewidea,muchpreliminaryactivityandoptimisticdiscussionproducednoconcreteproposals.
现在许多中大型企业建有企业数据仓库。关于数据仓库中数据的特点,下列说法一般情况下正确的是()。
DadCan’tHandleTheseToysAnyparentwithachild【C1】______theagesof3and11cantellyou【C2】______technologyhascrept
最新回复
(
0
)