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
考研
A. Cloud-to-ground lightening occurring in the U. S. B. Types of lightening C. Cause of lightening D. Differences between thunde
A. Cloud-to-ground lightening occurring in the U. S. B. Types of lightening C. Cause of lightening D. Differences between thunde
admin
2012-05-19
42
问题
A. Cloud-to-ground lightening occurring in the U. S.
B. Types of lightening
C. Cause of lightening
D. Differences between thunder and thunderstorm
E. Frequencies of thunderstorms occurring in the world and the U. S.
F. Shock waves as thunder
G. Forming process of lightening
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.
41. ______
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.
42.______
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.
43. ______
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.
44. ______
Thunder is generated by the tremendous heat released in a lightning discharge. Temperatures near the discharge can reach as high as 50,000T within thousandths of a second. This sudden heating acts as an explosion, generating shock waves we hear as thunder.
45. ______
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.
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
段落中提到了种种闪电类型(intra—cloud lightning,cloud-to-ground lightning,ball lightning)及对它们的相关介绍,因此判断B是答案。
转载请注明原文地址:https://kaotiyun.com/show/hNp4777K
0
考研英语一
相关试题推荐
Highoilpriceshavenotyetproducedaneconomicshockamongconsumingcountries,butfurtherrises,especiallysharp(1)_____,
Highoilpriceshavenotyetproducedaneconomicshockamongconsumingcountries,butfurtherrises,especiallysharp(1)_____,
Highoilpriceshavenotyetproducedaneconomicshockamongconsumingcountries,butfurtherrises,especiallysharp(1)_____,
Admittedly,minoraccidentsandslipupscontinuetoshakepublicconfidenceinnuclearpower.Giventheunquantifiablerisk
Title:PeopleShouldbeRewardedAccordingtoAbility,ortoAgeandExperienceYourcompositionshouldbebasedontheoutline
Whatequipmentonashipwasmadefromhemp?Waydoagriculturaliststhinkthathempwouldbebetterforpaperproductionthan
FromthefirsttwoparagraphswecanlearnthatthetrendoffoodobsessionisThephrase"globalcuisine"(Paragraph4)probabl
Eatingbetterandmoreadventurouslyisbecominganobsession,especiallyamongpeoplewithmoneytospend.Healthiereatingand
WhichofthefollowingreflectsthechangeofCatholicChurch?Therelationshipbetweenthefirsttwoparagraphscanbedescrib
NiagaraisanIndianwordwhichmeans"roaringwater".Indeed,theroarofthefallingwaterofNiagaracanbeheard(1)_____a
随机试题
参与补体三条激活途径的成分是
抗菌谱广、副作用小的喹诺酮类药物是()。
有关口服铁剂的注意事项,错误的是
根据有关规定,国有企业实施改制时应当明确企业与职工的相关责任。下列有关国有企业改制时企业与职工关系问题的表述中,正确的有()。
简述组织结构设计的步骤和部门结构选择的方式。
A、 B、 C、 D、 B第一组字母都是开放图形,第二组字母都是完全封闭图形。
Governmentisnotmadeinvirtueofnaturalrights,whichmayanddoexistintotalIndependenceofit;andexistinmuchgreate
中国佛教建筑的发展可以追溯到佛教在汉代被引入中国时。佛教的本土化也从此时开始,阐释着中国建筑的美学和文化。佛教建筑主要包括庙宇、佛塔和石窟。佛教建筑被视为一个将书法、雕塑和绘画结合起来的伟大艺术宝库。在中国,佛教始终也没有像基督教在西方那样,获得
【F1】Formorethantwodecades,U.S.courtshavebeenlimitingaffirmative-actionprogramsinuniversitiesandotherareas.Thel
将考生文件夹下JUNE文件夹中的文件KU.WPS删除。
最新回复
(
0
)