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.
*
选项
答案
E
解析
第六段列举了闪电及雷雨在地球上和在美国每年和每日发生的数据。
转载请注明原文地址:https://kaotiyun.com/show/LNGd777K
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
EtaCarinaeisnowengaginginAstronomersareparticularlyinterestedinEtaCarinaebecause
Peoplefrommanyplacesweredrawntothecitybyitsgrowingeconomy.
Stressleveliscloselyrelatedto______.Less-educatedpeoplereportfewerdaysofstresspossiblybecause______.
A.concernedwiththeproblemsthatwewillhavetosolveinthefutureB.readingbooksofsciencefictionC.politicalimplica
PuertoRicanCuisine(菜肴)PuertoRico,aCaribbean(加勒比海区)islandrichinhistoryandremarkablenaturalbeauty,hasacuisine
WhichofthefollowingstatementsaboutFlowersandYeoistrue?Theattitudeoftheauthortowardstheresearchprojectis
FewFactsaboutSingapore1.SingaporeisanindependentcitystateinsoutheasternAsia,consistingofonemajorisland—the
WilliamFaulkner’sstoriesreflecthisMississippiupbringing.
ThepoetWilliamCarlosWilliamswasaNewJerseyphysician.
Whatarethetwodeclarationsconcernedwith?Thephrase“kickedaround”(paragraph4)couldbebestreplacedby
随机试题
诗经中描述祭祀和颂圣的篇目,题材是六艺中的()。
急性阑尾炎发病已4天,腹痛稍减轻,但仍发热,右下腹可触及有压痛的肿块,应()
肝素的抗凝机制是
男,36岁。头昏、乏力3年,血压160/100mmHg,血红蛋白80g/L,尿比重1.014,尿蛋白(++),颗粒管型0~2/HP,BUN16.4mmol/L(46mg/dl),血肌酐309.4μmol/L(3.5mg/dl)。眼底视网膜动脉细窄迂
患者男,60岁,长期高脂饮食,近来发现排便次数增多,腹泻,持续性腹部隐痛,腹部可触及肿块,固定、压痛。怀疑结肠癌,患者接下来应该做的检查是
非淋菌性尿道炎的病原体以沙眼衣原体和支原体为主。()
黄林是国有企业的财务科科长、会计师,不仅自己业务能力强,而且经常组织全科的同志学习会计业务,对别人的提问也是耐心回答。小刘刚从事会计工作不久,每次碰到不懂的业务问题都喜欢问黄林科长,他总是耐心回答,直到小刘明白为止。然而,就是这样一位好科长,上个月却被莫名
试比较各种寻址方式的效率,以下结论中不正确的是()。
在考生文件夹中完成如下综合应用:在考生文件夹中有“仓库”数据库CHAXUN3包括三个表文件:ZG(仓库号C(4),职工号C(4),工资N(4))DGD(职工号C(4),供应商号C(4),订购单号C(4),订购日期D,总金额N(10)
A、Itwasinteresting.B、Itwasboring.C、Itwasdiscouraging.D、Itwasmoving.D本题考查对关键词汇的理解能力。对话中男士说今天早上那个盲童讲的话深深打动了我,女士答,我想每个人
最新回复
(
0
)