首页
登录
职称英语
The electromagnet was invented in England by William Sturgeon, who took an i
The electromagnet was invented in England by William Sturgeon, who took an i
游客
2025-03-21
23
管理
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. [br] Henry’s electromagnet was______.
选项
A、exactly like Sturgeon’s
B、an improvement over Sturgeon’s
C、more dangerous than Sturgeon’s
D、not as good as Sturgeon’s
答案
B
解析
本题是一道具体细节题。问亨利的电磁铁与斯特杰恩的电磁铁有什么区别。文章第二段指出,在美国,一位名叫约瑟夫·亨利的科学家改进了斯特杰恩的电磁铁,他用丝绸将铜导线进行绝缘处理。这样他便能够在铁芯上缠绕许多圈导线,而不会在线圈的匝间造成短路的危险。他的电磁铁可以吸起2 300磅的铁。因此,本题的正确答案应是B“亨利的电磁铁是斯特杰恩的电磁铁的改进”。
转载请注明原文地址:https://tihaiku.com/zcyy/4007086.html
相关试题推荐
Englandisnotabigcountry:fromnorthtosouthandfromeasttowestiti
Englandisnotabigcountry:fromnorthtosouthandfromeasttowestiti
Englandisnotabigcountry:fromnorthtosouthandfromeasttowestiti
Englandisnotabigcountry:fromnorthtosouthandfromeasttowestiti
TheelectromagnetwasinventedinEnglandbyWilliamSturgeon,whotookani
EvenifThomasEdisonhadn’tinventedtheelectriclightsuccessfully,we______
AchainofshopsinEastYorkshire,Englandhasbeentoldthatitwouldbea
AchainofshopsinEastYorkshire,Englandhasbeentoldthatitwouldbea
AchainofshopsinEastYorkshire,Englandhasbeentoldthatitwouldbea
AchainofshopsinEastYorkshire,Englandhasbeentoldthatitwouldbea
随机试题
Thinkaboutwhatwouldmakeyoureally,reallyhappy.Moremoney?Wrong.Smi
HowisJackyrecently?[br][originaltext]F:Hey,jack!Howareyouthesedays?
Whichofthefollowingisthemaintopicofthenews?[originaltext]Germany
Directions:forthispart,youareallowedthirtyminutestowriteacomposition
全血的粘滞性主要取决于A.血浆蛋白含量 B.红细胞数量 C.白细胞数量 D
关于货币的时间价值,下列表述正确的有()。 Ⅰ.现值与终值成正比例关系 Ⅱ
“我们敢说日常所见的人中。十分之九都是他们的教育所决定的”,这一观点是出自洛克的
对这个政策有一些人感到不那么顺眼,我们的做法是允许不同观点存在,拿事实来说话。农
下列哪项不是骨折功能复位的标准? A.儿童下肢缩短移位2cmB.侧方成角移
在高科技时代强调医学偷教育的必要性,最主要的原因在于医学高新技术A.促进了医学发
最新回复
(
0
)