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
The electromagnet was invented in England by William Sturgeon, who took an iron rod and bent it into the shape of a horseshoe. T
The electromagnet was invented in England by William Sturgeon, who took an iron rod and bent it into the shape of a horseshoe. T
admin
2014-04-23
13
问题
The electromagnet was invented in England by William Sturgeon, who took an iron rod and bent it into the shape of a horseshoe. This "horseshoe" was coated with varnish (清漆) and a layer of copper wire was wrapped around it. An electric current was passed through the wire, thus making the rod magnetic. The rod was now, because of magnetic attraction, able to support nine pound of iron.
In the US, a scientist named Joseph Henry improved on Sturgeon’s electromagnet by insulating (使绝缘) the copper wire with silk. He was able to wrap many turns of wire around an iron core without danger of circuits between the turns. His magnet could hold 2 300 pounds.
This experiment prompted Henry to try his hand at converting magnetism into electricity. First he coiled (缠绕, 盘绕) some insulated wire around an iron bar, connecting both ends of the wire to a galvanometer (电流计). The iron bar was placed across the poles of the electromagnet. Then the coil of the electromagnet was connected to a battery. The galvanometer indicated a voltage , then dropped to zero. Henry signaled his assistant to disconnect the coil. The galvanometer showed that once again a voltage had been produced, although this time in the opposite direction. The principle of electromagnet induction (感应现象) had thus been discovered. Unfortunately for Joseph Henry he did not publish findings and someone else (Faraday) got the credit for the discovery.
Henry was encouraged by his experiment______.
选项
A、to insulate the copper wire
B、to change magnetism into electricity
C、to convert electricity into magnetism
D、to avoid short circuits
答案
B
解析
本题问亨利受改进试验的鼓励,打算做什么试验。文章第三段第一句话指出,这一实验促使亨利着手搞起了磁、电转换实验。因此,本题的正确答案应是B“将磁转换成电”。
转载请注明原文地址:https://kaotiyun.com/show/6bWO777K
0
在职攻硕英语联考
相关试题推荐
MillionsofpeopleintheUnitedStatessufferfrom______backpainthatcomesfromsittingtoolongatadesk.
WhenAmericanastronautGlenreturnedtotheearthandaheartywelcome______him,hewasconsideredtobeanationalhero.
Withinhoursofappearingontelevisiontoannouncetheendofconscription,PresidentJacquesChiracmovedquicklytopreventa
RichardSatava,programmanagerforadvancedmedicaltechnologies,hasbeenadrivingforcebringingvirtualrealitytomedicine
Somepeoplefeelthattelevisionshouldgiveless______tosport.
PresidentCoolidge’sstatement,“ThebusinessofAmericaisbusiness,”stillpointstoanimportanttruthtodaythatbusinessin
Oilcanchangeasocietymore_________thananyonecouldeverhaveimagined.
Itbeganasjustanotherresearchproject,inthiscasetoexaminetheeffectsofvariousdrugsonpatientswithaseveremoodd
Britain’semissionsofgreenhousegases,blamedbymanyscientistsforcontributingtoglobalwarming,havefallenby14percent
随机试题
某企业2008年1月银行存款日记账20日至月末的所记经济业务如下:(1)20日开出支票#09478,支付购入材料的贷款1400元。(2)21日存入销货款转账支票2400元。(3)24日开出支票#09479,支付购料运杂费700
肾岩好发年龄为:
A.宜佐健脾和胃、凉肝定惊之品B.忌用有肾毒性的药物C.忌用有肝毒性的药物D.应慎用在母乳中浓度高的中药E.一般应从“最小剂量”开始婴幼儿患者中药的使用应
患者,女性,26岁,患肝硬化伴食管静脉曲张破裂出血。入院第2天,行三腔双囊管压迫止血,护士需要给患者进行护理评估,但应险外
会计核算提供的信息应当符合国家宏观管理的要求,满足各方了解企业财务状况和经营成果的需要,满足会计内部管理的需要,称为会计信息质量要求原则中的()。
正整数x是一个完全平方数。(1)对于每一个质数p,p是x的一个因子,p2也是x的一个因子;(2)是一个整数。
在存在逆向选择的保险市场上,以下哪种情况最有时能发生?()。
下列宏操作中限制表、窗体或报表中显示的信息的是()。
Thetrainclatteredoverpointsandpassedthroughastation.Thenitbegansuddenlytoslowdown,presumablyinobediencetoa
A、Thereisagreatdifferencebetweenreadingandlistening.B、Thereareeffectivewaystopracticetheproofreadingskill.C、Hi
最新回复
(
0
)