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
65
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
D
解析
第二段谈到了“对闪电过程没有全部弄清楚”(though processes are still not fully understood…),但是,第二段至第四段解释了闪电的成因及闪电的类型和形状。人类对闪电、雷雨现象具有相当充分的了解。
转载请注明原文地址:https://kaotiyun.com/show/1NGd777K
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
CaribbeanIslandsWhatwouldyouseeifyoutookacruisetotheCaribbeanIslands?Palmtreesandcoconuts(椰子)?Whitebeaches
CanBuildingsbeDesignedtoResistTerroristAttackIntheaftermathoftheterroristattackontheWorldTradeCenter,str
SomeUnusualCelebrationsSomeholidaysarewell-knownallaroundtheworld.AmongthemareNewYearsEvecelebrations.Al
HowtoBeaSuccessfulBusinesspersonHaveyoueverwonderedwhysomepeoplearesuccessfulinbusinessandothersarenot?
PuertoRicanCuisine(菜肴)PuertoRico,aCaribbean(加勒比海区)islandrichinhistoryandremarkablenaturalbeauty,hasacuisine
CompactDisksIfsomeonesaystoyouyourmusicCDsdon’treallyholdanymusiconthem,andtheyonlyhavenumbersrecorde
WhereDidAlltheShipsGo?TheBermudaTriangleisone【C1】______thegreatestmysteriesofthesea.Inthistriangulararea
Howcanthecreditcardrecognizethespokenpasswordgivenbytheuser?Whatisthemaindifferencebetweentheearliermodel
ListeningDeviceProvidesLandslide(山崩;地滑;塌方)EarlyWarningAdevicethatprovidesearlywarningofalandslidebymonitoring
MariaChapman,abolitionistandcloseassociateofWilliamLloyedGarrison,wrotemanybrochurescondemningslavery.
随机试题
支配大鱼际肌的神经为
中医精气神学说的“精”是指
乙是一个卖淫女,甲曾多次给她介绍嫖客。后来乙将新结识的妇女丙介绍给甲,甲得知丙愿意从事卖淫的消息后,先后三次容留、介绍丙卖淫。此后,丙表示不干了,但甲威胁说如果丙不继续干,就去司法机关告发其以前的卖淫行为,丙由于惧怕只好继续接受甲为她介绍的嫖客。公安机关根
银行办理个人汽车贷款时,可以将贷前调查工作全权委托给保险公司和汽车经销商进行。()
企业转让金融商品,年末,如“应交税费——转让金融商品应交增值税”有借方余额,正确的会计处理是()。
某企业拟进行一项固定资产投资项目决策,资本成本为12%,有四个方案可供选择。其中甲方案的项目计算期为5年,净现值为1000万元;乙方案的现值指数为0.85;丙方案的项目计算期为11年,净现值的等额年金为150万元;丁方案的内含报酬率为10%。最优的投资方案
【B1】【B10】
Histheoryturnedouttobevery(effect)______toimproveourexperiment.
A、Themanshouldwaitforawhile.B、Themanshouldkeepitasasecret.C、Shewouldliketoknowaboutthatproblem.D、Theman
A、Professionalathletes.B、Amateurathletes.C、Peoplewhooftentravel.D、Peoplewhooftenlacksleep.D
最新回复
(
0
)