首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Volts from the Sky 1.Lightning has caused awe and wonder since old times. Although Benjamin Franklin demonstrated lightning a
Volts from the Sky 1.Lightning has caused awe and wonder since old times. Although Benjamin Franklin demonstrated lightning a
admin
2010-01-13
45
问题
Volts from the Sky
1.Lightning has caused awe and wonder since old times. Although Benjamin Franklin demonstrated lightning as an enormous electrical discharge more than 200 years ago, many puzzles still surround this powerful phenomenon.
2.Lightning is generated when electrical charges separate in rain clouds, though processes are still not fully understood. Typically, positive charges build at the cloud top, while the bottom becomes negatively charged. In most instances of cloud-to-ground lightning, the negatively charged lower portion of the cloud repels negatively charged particles on the ground’s surfaces, making it become positively charged, The positive charge on the ground gathers at elevated points.
3.A flow of electrons begins between the cloud and earth. When the voltage charge becomes large enough, it breaks through the insulating barrier of air, and electrons zigzag earthward. We see the discharge as lightning.
4.Lightning can occur within a cloud, between clouds, or between clouds and the ground. The first variety, intra-cloud lightning, is the most frequent but is often hidden from our view. Cloud-to -ground lightning, making up about 20 percent of lightning discharges, is what we usually see lightning comes in several forms, including sheet, ribbon, and ball, Intra-cloud lightning can illuminate a cloud so it looks like a White sheet, hence its name. When cloud-to-ground lightning occurs during strong winds, they can shift the lightning channel sideways, so it looks like a ribbon. The average lightning strike is more than 3 miles long and can travel at a tenth of the speed of light. Ball lightning, the rarest and most mysterious form, derives its name from the small luminous ball that appears near the impact point, moves horizontally, and lasts for several seconds.
5.Thunder is generated by the tremendous heat released in a lightning discharge second. This sudden heating acts as an explosion, generating shock waves we hear as thunder.
6.About 2,000 thunderstorms are occurring in the world at any time, generating about 100 lightning strikes every second, or 8 million daily. Within the United States, lightning strikes are estimated at 20 million a year, or about 22,000 per day. You have a 1-in-600,000 chance of being struck by lightning during your lifetime. Lightning can strike twice or more in the same spot. The Empire State Building in New York is struck by lightning about two dozen times annually.
7.You can measure how far you are from a lightning strike by counting the seconds between viewing the flash and hearing the bang, and then dividing by five. This approximates the mileage.
*
选项
答案
B
解析
第四段介绍了闪电的三种类型;云层内部闪电,云层与云层之间的闪电,云层与地面之间的闪电。此外,还从形状上介绍了闪电可有片状、带状和球状。
转载请注明原文地址:https://kaotiyun.com/show/FNGd777K
本试题收录于:
职称英语综合类基础题库职称英语分类
0
职称英语综合类基础
职称英语
相关试题推荐
ThepeopleofKiribatiworrythatonedaytheircountrywillbetakenawaybyasuddenhightide.Thecoralislandnationsoft
SaveEnergyAtHomeOntheaverage,Americanswasteasmuchenergyastwo-thirdsoftheworld’spopulationconsumes.That’slar
StoneHillMallisdifferentfromothermallsbecauseithasItisimpliedinthepassagethatthewritertakesa(n)______att
Asmembersdroppedout,theclubbecamesmallerandsmaller.
Graphene’sSuperstrengthBigtechnologycomesintinypackages.Newcellphonesandpersonalcomputersgetsmallereveryyear
ThetiesymbolizesalloftilefollowingexceptWhydoesBlairsometimesshowupinaformaleventwithoutatie?
UrbanRainforestOnthewestsideoftheislandofManhattaninNewYorkCity,treebytree,leafbyleaf,a2,500squarefoo
ModerateEarthquakeStrikesEnglandAmoderateearthquakestruckpartsofsoutheastEnglandon28April2007,topplingchimn
随机试题
硬盘工作时应特别注意避免__________。()
杀灭细菌芽孢最常用的方法是()
医学伦理学的研究内容不包括以下哪一项
企业开业、变更名称、注销,由()发布企业法人登记公告。
某环评机构在为位于M市某化工厂建设项目做环境影响评价的过程中,发现根据《中华人民共和国环境影响评价法》的规定在制作公众参与篇章时无须召开听证会,而根据《环境影响评价公众参与暂行办法》的规定须召开听证会,则应()。
只用本金计算利息称为()。
()是指根据被代理人的委托而产生的代理。
各相关机关和单位在实施工程建设强制性标准的监督管理中的作用是()。
审计证据必须具有______的价值和______的价值。
社会主义法治理念是中国特色社会主义的法治理念,包含“依法治国、执法为民、公平正义、服务大局、党的领导”五个方面的基本内涵。其中,属于社会主义法治核心内容的是
最新回复
(
0
)