首页
财务会计
医药卫生
金融经济
考公考编
外语考试
学历提升
职称考试
建筑工程
IT考试
其他
登录
职称考试
Learn about Light 1 Ancient civilizations were amazed by the existence of li...
Learn about Light 1 Ancient civilizations were amazed by the existence of li...
admin
2020-12-24
44
问题
Learn about Light
1 Ancient civilizations were amazed by the existence of light for thousands of years. The Greek philosophers believed thatlight was made up of countless, tiny particles that enter the human eye and create what we call vision. However , Empedocles and a Dutch scientist named Christian Huygens believed that light was like a wave. According to them, light spread out and travelled like a straight line. This theory was accepted during the 19th century.
2 In 1905,Albert Einstein published a research paper in which he explained what is referred to as the photoelectric effect. This theory explains that particles make up light. The particles Einstein was referring to are weightless bundles (束)of electromagnetic (电磁) energy called photons (光子)_ Today, scientists agree that light has a dual ( 二重) nature — it is part particle and part wave. It is a form of energy that allows us to see things around us. .
3 Things that give off light are known as sources of light. During the day, the primary source of light is the sun. Other sources of light include stars, flames, flashlights, street lamps and glowing gases in glass tube.
4 When we draw the way light travels we always use straight lines. This is because normally light rays travel in a straight line. However, there are some instances that can change the path and even the nature of light. They are reflection, absorption, interference (干扰),etc.
5 Physicists have attempted to measure the speed of light since the early times. In 1849, Hippolyte Fizeau conducted an experiment by directing a beam of light to a mirror located kilometers away and placed a rotating cogwheel (旋转齿轮)between the beam and the mirror. From the rate of rotation of the wheel,number of wheel’s teeth and distance of the mirror, he was able to calculate that the speed of light is 313 million meters per second. In a vacuum (真空),however, the speed of light is 299,792,458 meters per second. This is about a million times faster than the speed of an airplane.
Objects are visible to the human eye as light is _______
选项
A a straight line
B a beam of light
C sources of light
D the path of light
E a form of energy
F the speed of light
答案
E
解析
根据第二段最后一句:It (light) is a form of energy that allows us to see things around us. visible-可以看到的。
转载请注明原文地址:https://ti.zuoweng.com/ti/z79QKKKQ
相关试题推荐
Theydidn’tseemtoappreciatethemagnitudeoftheproblem.A.existenceB.caus
共用题干 OlderVolcanicEruptionsVolcanoesweremoredestructiveinancienthist...
共用题干 OlderVolcanicEruptionsVolcanoesweremoredestructiveinancienthist...
共用题干 OlderVolcanicEruptionsVolcanoesweremoredestructiveinancienthist...
第三篇TheWorld’sBest-SellingMedicine Sinceancienttimes,peopleallover...
弟一篇TheWorkfsBest-Se川ngMedicine Sinceancienttimes,peoplealloverthe...
弟一篇TheWorkfsBest-Se川ngMedicine Sinceancienttimes,peoplealloverthe...
Theydidn’tseemtoappreciatethemagnitudeoftheproblem.AexistenceBcause
共用题干 第三篇TheWorld'sBest-SellingMedicineSinceancienttimes,peopleallov...
共用题干 第三篇TheWorld'sBest-SellingMedicineSinceancienttimes,peopleallov...
随机试题
(61-62题共用备选答案) A.羌活胜湿汤 B.败毒散 C.三仁汤 D
目前评价营养状况最普遍和最重要的方法是 A、体重 B、皮皱厚度 C、体
在FIDIC施工合同下,发包人人员引起的延误、妨碍,承包商有权索赔( )。 A
C
应收账款保理对于企业而言,其财务管理作用不包括()。
诊断戈谢病最可靠的方法是
某医院外科手术室的面积为30m2,院方要求手术室一般照明与室内:医疗设备均为一级
病人对医生的问题只能在表面先产生反应,缺乏进一步的联想,该症状为 A.思维被
问题解决策略主要包括{pz_填空}和启发式策略。
通常将闪点小于___℃的液体归为甲类火灾危险性物质。A.-18B.23C.28D.60