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
31
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.
A.Cloud-to-ground lightning occurring in the U. S.
B.Types of lightning
C.Cause of lightning
D.Differences between thunder and thunderstorm
E.Frequencies of thunderstorms occurring in the world and the U. S
F.Shock waves as thunder
选项
答案
C
解析
第二段以云层到地面的闪电为例子解释了闪电的原理。第三段述及闪电发生的过程。
转载请注明原文地址:https://jikaoti.com/ti/NEysFFFM
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
SaveEnergyAtHomeOntheaverage,Americanswasteasmuchenergyastwo-thirdsoftheworld’spopulationconsumes.That’slar
TestsShowWomenSuitedforSpaceTravelBetween1977and1981,threegroupsofAmericanwomen,numbering27inall,betweenth
TheSmog(烟雾)Foroveramonth,Indonesiawasincrisis.Forestfiresragedoutofcontrolasthecountrysuffereditsworstdr
Migrant(移民的)WorkersInthepasttwentyyears,therehasbeenanincreasingtendencyforworkerstomovefromonecountrytoa
AlmostHuman?Scientistsareracingtobuildtheworld’sfirstthinkingrobot.Thisisnotsciencefiction:somesaytheywill
IrarelyweararaincoatbecauseIspendmostofmytimeinacar.
CropProblemAdvancesintechnologyhavehelpedmoreoftheworld’spopulationlivebetterandlonger,andthatispartofo
PushbikePerilLowspeedbicyclecrashescanbadlyinjureorevenkillchildreniftheyfallontotheendofthehandlebars
SeeingRedMeansDangerAheadThecolorredoftenmeansdanger-andbypayingattention,accidentscanbeprevented.Inthefutu
WhereDidAlltheShipsGo?TheBermudaTriangleisone【C1】______thegreatestmysteriesofthesea.Inthistriangulararea
随机试题
Theboatsailedslowly,keeping______tothecoastasthemaninitwasafraidof______thedirection.
张某投资设立了甲个人独资企业,以下说法正确的是:()
二次灌浆时,当灌浆层要求与设备底座底面接触较密实时,宜采用()灌浆。
实施电子转单后,依据《口岸查验管理规定》相关规定,口岸检疫机构()。
世界观和人生观的关系是()。
水资源短缺一直是我围在人口增长、城市化和工业化过程中所面临的一个长期的、趋势性的问题,成为制约我国经济发展的一大瓶颈。专家认为,海水淡化是沿海及临海地区最经济、最实用、最灵活的水危机解决方案。随着技术的进步,海水淡化的成本将逐步降低,最终将达到与成本正逐步
简述德意志帝国从建立到1900年前后主要的外交政策。(华南师范大学2006年世界近现代史真题)
下列命题中属于揭示事物本质的有
事务内部故障可以分为预期的和非预期的,运算溢出故障属于____________的事务内部故障。
TheChineseNewYearisabigtraditionalholidayinSingapore.OnitsEve,whilemanywill【C1】______forthereuniondinner,o
最新回复
(
0
)