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 White light seems to be a combination of all colors. The energy that comes from a source of light is
Electromagnetic Energy White light seems to be a combination of all colors. The energy that comes from a source of light is
admin
2013-08-28
26
问题
Electromagnetic Energy
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.
The sun is 93 million miles from the earth. Yet we can use energy from the sun because electromagnetic energy travels through space.
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 right 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.
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.
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).
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 Lasting 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 4______.
选项
答案
B
解析
第四段主题句为第二句The source of most of our energy is the sun,我们使用的大部分能量都来自太阳。由此可推知,来自太阳的能量(即电磁能)对人类来说是非常重要的。B选项The Most Important Source of Energy与其意思一致。故B为正确答案。
转载请注明原文地址:https://kaotiyun.com/show/yaLd777K
本试题收录于:
职称英语理工类A级题库职称英语分类
0
职称英语理工类A级
职称英语
相关试题推荐
MobilePhonesMobilephonesshouldcarryalabeliftheyprovedtobeadangeroussourceofradiation,accordingtoRobertBell,
WhydoestheauthorthinktheEiffelToweristransformedintosymbolofaworldonthemove?WhichstatementisNOTtrueofHu
Whichmineralshavebeenprovedtobeinsufficient?Accordingtothepassage,whatisthepurposeofChina’sgeologicalresearc
Accordingtothepassage,howcanyoulearnthatmanypeopleareuneasyaboutinformationtechnology?Accordingtothepassage,
Stinking(发臭的)BusesStinkingbusesjam(挤满)thecrowdedstreet.Drivers(51)atoneanotherandhonk(鸣喇叭)theirhorns.Smog(烟雾)hurt
Stinking(发臭的)BusesStinkingbusesjam(挤满)thecrowdedstreet.Drivers(51)atoneanotherandhonk(鸣喇叭)theirhorns.Smog(烟雾)hurt
AFactorsLeadingtoEnergyWasteBHomeAppliancesCPropsalstoCutEnergyConsumptionDEnergyConsumptionTestETerawa
GlobalWarmingAttheKyotoconferenceonglobalwarminginDecember1997,itbecameabundantlyclearhowcomplexithasb
GlobalWarmingAttheKyotoconferenceonglobalwarminginDecember1997,itbecameabundantlyclearhowcomplexithasb
EarthquakeEveryyearearthquakesareresponsibleforalargenumberofdeathsandavastamountofdestructioninvarious
随机试题
假定,中国人民银行某年公布的货币供应量数据为(单位:亿元):[*9]广义货币是指()。
简述非马克思主义者划分政体的标准。
关于原子的核外结构的叙述,正确的是
对山东省人民政府具体行政行为的复议申请,应向()申请行政复议。
设备安装工程具备无负荷联动试车条件,由()组织试车。
编辑加工题:按发稿要求以规范的方式对短文进行编辑加工整理。张元济张元济出生于浙江省海盐县名门旺族,幼承家学,26岁即考中进士,甲午战争失败后,张元济开始学习英文,倡导新政与变法
省委的文件同时发给市委、县委,这种行文方式属于()。
某个全国公司拟在总部及全国各地分公司安装一种电脑话务员系统。该系统使消费者通过电脑话务员拨打接线员接入电话,即使如此,在可预见的将来,人工接线员的数量仍不会减少。以下各项有助于解释人工接线员不会减:少,除了:
有以下程序#includevoidf(int*p,int*q);main(){intm=1,n=2,*r=&m;f(r,&n);printf("%d,%d",m,n);}voidf(int*p,int*q){p=p+1;*q=*q+
Ifyou’vebeenfollowingthestatusofArcticseaiceforthepastfewyears,hearingscientists【C1】______thepotentialcomingo
最新回复
(
0
)