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  3. 共用题干 Electromagnetic Energy1 White light seems to be a combination of all co...

共用题干 Electromagnetic Energy1 White light seems to be a combination of all co...

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问题 共用题干
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 kind of energy that produce
warmth and sunburn are examples of electromagnetic energy.
2 The sun is 93 million miles away from the earth.Yct we can use energy from die sun because elec-
tromagnetic energy travels through space.
3 Many other kinds of energy are also types of electromagnetic energy.Radio,television,and radar signais
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.Wayes of infrared and visible light
have more energy than waves of radio,television,or radar. Ultraviolet rays（紫外线）and X-rays are eleetro-
magnetic 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.
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．入bout 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 chemi-
cal 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 elec-
tricity.It is also being used to operate engines in large ships.Scientists continue to seek new and better
methods of obtaining and using energy.
选项 Visible light that produces warmth is an example of _______________.
A:electromagnetic energy
B:electromagnetic energy travels through space
C:came from the sun
D:when a change in the nucleus of an atom takes place
E:whlen the sunrays are fierce
F:chemical energy is generated
答案A
解析第三段的第一句为主题句，意为：许多其他种类的能量也是不同类型的电磁能。该段 列举了电磁能的具体例子，C项“Types of Electromagnetic Energy（电磁能的类型）”与主题句意 思吻合，故选C。
第四段的第二句为主题句，意为：我们的能量大多来白太阳。B项“The Most Important Source of Energy（最重要的能量来源）”与主题句意思吻合，故选B。
第五段的最后一句为主题句，意为；我们现在相信太阳的能量来自核反应，在此过程 中，氢转变为氦。A项“Nuclear Reactions as the Lasting Source of the Sun' s Energy（核反应是太 阳能最持久的来源）”与主题句意思吻合，故选A。
第六段的最后一句为主题句，意为：科学家仍在继续寻找获取和使用能量的新的、更好 的方法。E项“Seeking New Sources of Energy（寻找新的能源）”与主题句意思吻合，故选E。
第一段的最后一句指出，“可见光和其他能产生热量和造成晒伤的能量都是电磁能的 例子”。故选A。
第二段的第二句指出，“我们能使用太阳能，因为电磁能可以在太空中穿梭”。故选B。
第四段的最后一句指出，“其他的发电机靠煤炭驱动，但是，煤炭中储存的能量也来自 于太阳”。C项中的“came from the sun (来自太阳）”与原句意思相符，故选C。
第五段的第五句指出，化学能来自于电子重组。故选F。第4部分：阅读理解第一篇 本文介绍了引起食物中毒的原因及食物中毒的预防和治疗处理措施。
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