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
42
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.
Some instances such as reflection and absorption can change ________
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
D
解析
第四段倒数第二句中的some instances就是指代倒数第一句中的reflection, absorption, interference
转载请注明原文地址:https://ti.zuoweng.com/ti/I79QKKKQ
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...
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...
随机试题
人防工程内不应设置( )。 A.哺乳室 B.幼儿园 C.托儿所
房贷险的第一受益人是()。[2015年10月、2013年6月真题] A.贷款
受理申请宣告公民失踪或死亡的机关是人民法院。( )
业主大会成立前,重托商业银行开立的住宅专项维修资金专户()。
2013年12月26日,中国社科院和社会科学文献出版社共同发布的《社会蓝皮书》显
乘车时,急刹车,右膝前方受到撞击。出现右髋剧痛,髋关节运动障碍,处于屈曲、内收、
下列哪项内容有助于鉴别肾盂肾炎和膀胱炎A.尿中WBC++/HPB.尿路刺激征C.腰痛明显D.尿中有白细胞管型E.尿WBC+/HP,RBC5~10个/HP
以下关于宪法特征的描述错误的是() A.宪法具有最高的法律效力,所有其他的法都不得和宪法相抵触 B.宪法是包括执政党在内的一切组织和个人的最高行为...
朱某系某县民政局副局长,率县福利企业年检小组到同学黄某任厂长的电气厂年检时,明知该厂的材料有虚假、残疾员工未达法定人数,但朱某以该材料为准,使其顺利通过年...
一般性政策工具是中央银行运用最多的传统工具,具体包括()。A.再贴现率B.再贷款C.公开市场业务D.法定存款准备金率E.信贷规模