光反应(light reactions)
光反应(light reactions)
相关考题：
Electromagnetic EnergyWhite 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 EnergyB. The Most Important Source of EnergyC. Types of Electromagnetic EnergyD. X-rays Are Used to Detect and Treat Cancer.E. Seeking New Sources of EnergyF. Nuclear Energy is Beginning to Compete with CoalParagraph 3 ______
A light used to signal passing intentions must be an ______.A.all-round yellow light onlyB.all-round white light onlyC.all-round blue light onlyD.alternating red and yellow light
An anchored vessel on pilotage duty must show which light(s) at night?A.A sternlight onlyB.Anchor lights onlyC.A white light over a red light onlyD.A white light over a red light and anchor lights
A vessel trawling will display a ______.A.red light over a white lightB.green light over a white lightC.yellow light over a red lightD.white light over a green light
A buoy marking a wreck will show a(an) ______.A.white light FL (2) and a topmark of 2 black spheresB.occulting green light and may be letteredC.yellow light and will be numberedD.continuous quick white light and may be numbered
共用题干Electromagnetic Energy1 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.Infrared radiation can produce heat______. A:when it is absorbed by matterB:when it is cloudyC:because they can pass through solid objectsD:when the sunrays are fierce.E:when a change in the nucleus of an atom takes placeF:when electron rearrangement takes place
共用题干Electromagnetic Energy1 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 cloudyday 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.Yet we can use energy from the sun because elec-tromagnetic 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 electro- 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.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 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-tncity.It is also being used to operate engines in large ships.Scientists continue to seek new and better methods of obtaining and using energy.Paragraph 5_____________A:Nuclear Reactions as the Lasting Source of the Sun's EnergyB:The Most Important Source of EnergyC:Types of Electromagnetic EnergyD:X-rays Are Used to Detect and Treat CancerE:Seeking New Sources of EnergyF:Nuclear Energy Is Beginning to Compete With Coal
共用题干Electromagnetic Energy1 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 cloudyday 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.Yet we can use energy from the sun because elec-tromagnetic 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 electro- 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.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 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-tncity.It is also being used to operate engines in large ships.Scientists continue to seek new and better methods of obtaining and using energy.Visible light that produces warmth is an example of______________.A:electromagnetic energyB:electromagnetic energy travels through spaceC:came from the sunD:when a change in the nucleus of an atom takes placeE:when the sunrays are fierceF:chemical energy is generated
产生彩色投影必须调整下面哪个参数（）A、light的light transmission设为100%B、light的light transmission设为0%C、投影层的阴影层的light transmission设为80%D、接受阴影层的light transmission设为100%
单选题The color of the exhaust from a diesel engine should be （）AclearBhazy light brownChazy light blueDhazy light grey
单选题（）are located on the road panel of main switchboard.AMegohm meter, insulation light and synchroscopeBSynchroscope, synchro light and megohm meterCShore power switch, insulation light and synchroscopeDMegohm meter, insulation light and shore power switch
单选题A buoy marking a wreck will show a(n)（）.Awhite light FL (2) and a topmark of 2 black spheresBocculting green light and may be letteredCyellow light and will be numberedDcontinuous quick white light and may be numbered
单选题An anchored vessel on pilotage duty must show which light(s) at night? （）AA sternlight onlyBAnchor lights onlyCA white light over a red light onlyDA white light over a red light and anchor lights
单选题A vessel trawling will display a（）.Ared light over a white lightBgreen light over a white lightCyellow light over a red lightDwhite light over a green light
单选题A hollow-cathode lamp is（）AA broad-band light sourceBA narrow-band light sourceCA light detectorDNot a light source
单选题打开锚灯！ （）ASwitch on the deck light!BSwitch on the anchor light!CSwitch on the cargo light!DSwitch on the hold light!
单选题A list signal of one white light indicates that the vessel is （）.Aon an even keelBlisting about 1° to the side the light is displayed onClisting over 5° With the light displayed on the high sideDlisting，and the chutes should be directed to the side where the light is displayed
单选题Which statement concerning Montauk Point Light is TRUE（）.AThe light comes on at sunsetBThere is an emergency light if the main light is extinguishedCThe height of the light is 24 feetDThe tower is painted with black and white stripes
单选题An alternating light（）.Ashows a light with varying lengths of the lighted periodBshows a light that changes colorCmarks an alternate lesser-used channelDis used as a replacement for another light
单选题Every field of chemistry _____ different chemical reactions.AholdsBconsistsCcomposesDinvolves
单选题A towing light is（）.Ashown below the sternlightBwhite in colorCdisplayed at the mastheadDa yellow light having the same characteristics as the stern light