第1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 kind 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 mush 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. X-rays Are Used to Detect and Treat Cancer.
E. Seeking New Sources of Energy
F. Nuclear Energy is Beginning to Compete with Coal
Paragraph 3 ______
第2题:
Jae Kwon gave examples in Paragraph 4_________.
A. to show chemical batteries are widely applied.
B. to introduce nuclear batteries can be safely used.
C. to describe a nuclear-powered system.
D. to introduce various energy sources.
细节理解题。根据文章第四段可知Kwon举例的目的是为了说明原子能电池是安全的,所以B项正确。
第3题:
A、frustrate
B、challenge
C、conquer
D、press
第4题:
第5题:
A、solver
B、solve
C、solving
D、solution
第6题:
D
Batteries can power anything from small sensors to large systems. While scientists are finding ways to make them smaller but even more powerful, problems can arise when these batteries are much larger and heavier than the devices themselves. University of Missouri(MU) researchers are developing a nuclear energy source that is smaller, lighter and more efficient.
“To provide enough power, we need certain methods with high energy density(密度)”,said Jae Kwon, assistant professor of electrical and computer engineering at MU. “The radioisotope(放射性同位素) battery can provide power density that is much higher than chemical batteries.”
Kwon and his research team have been working on building a small nuclear battery, presently the size and thickness of a penny, intended to power various micro / nanoelectromechanreal systems (M/NEMS). Although nuclear batteries can cause concerns, Kwon said they are safe.
“People hear the word ‘nuclear’ and think of something very dangerous,” he said, “However, nuclear power sources have already been safely powering a variety of devices, such as pace-makers, space satellites and underwater systems.”
His new idea is not only in the battery’s size, but also in its semiconductor(半导体). Kwon’s battery uses a liquid semiconductor rather than a solid semiconductor.
“The key part of using a radioactive battery is that when you harvest the energy, part of the radiation energy can damage the lattice structure(晶体结构) of the solid semiconductor,” Kwon said, “By using a liquid semiconductor, we believe we can minimize that problem.”
Together with J. David Robertson, chemistry professor and associate director of the MU Research Reactor, Kwon is working to build and test the battery. In the future, they hope to increase the battery’s power, shrink its size and try with various other materials. Kwon said that battery could be thinner than the thickness of human hair.
71. Which of the following is true of Jae Kwon?
A. He teaches chemistry at MU.
B. He developed a chemical battery.
C. He is working on a nuclear energy source.
D. He made a breakthrough in computer engineering.
细节理解题。根据第三段的叙述可知Kwon在研究一种原子能电池,所以C项正确。
第7题:
It is certain that men will never stop _____ new energy sources to power their growing industry.
A. finding
B. to find
C. having found
D. found
第8题:
Besides climate change, developing countries like China need to deal with energy【21】and environmental issues: the development of sources of clean energy needs to be【22】line with their interests. Clean energy has been given greater prominence than ever before; it is seen as a new industrial【23】and【24】of economic growth for the new century. The time for clean energy has come.
In China, clean energy is moving ahead at full speed. Take wind power as an example: by the end of last year, China had【25】wind power generating capacity of 12. 21GW, making China the largest wind power generator in Asia and fourth in the world. But according to the research, one-third of wind power capacity is running【26】due to an inability to get the power to the national【27】.
India-like China—relies【28】on coal for its energy needs. This will only change if the funds and technology to develop clean energy, such as wind and nuclear power, are【29】. India will not choose clean energy【30】. Nuclear power is currently the most【31】of clean energy sources.【32】, if it is to be【33】on a large scale by developing nations, technological advances will be needed to make it competitive with coal.
Compared【34】developed countries, developing countries have more【35】choices when it comes to energy structure. Promoting economic growth requires【36】energy—and coal, the cheapest and most【37】source of energy for many countries—is the【38】choice. Cheap coal means cheap electricity and a competitive economy. Rising electricity prices would cause public【39】and impact on standards of【40】.
(21)
A.scarce
B.scare
C.scarcity
D.scary
第9题:
A.solution
B.solving
C.solve
D.solver
第10题: