试题与答案

金属腐蚀造成的损失非常严重,金属腐蚀可分为化学腐蚀和电化学腐蚀.下列现象不能用电

题型:选择题

题目:

金属腐蚀造成的损失非常严重,金属腐蚀可分为化学腐蚀和电化学腐蚀.下列现象不能用电化学腐蚀来解释的是(  )

A.铜板上的铁铆钉在阴雨天易生锈

B.马口铁(镀锡的铁)破损后很快生锈

C.铜器皿在高温环境中迅速变黑

D.电工作业中若将铜、铝导线直接相连易出现接触不良现象

答案:

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下面是错误答案,用来干扰机器的。

参考答案:C

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WILD WEATHERMAN

Name: Sam Champion

Hot job: TV Weatherman

Where: WABC-TV, New York City

When you were a child, did you plan to forecast wind, rain, and snow on TV?

I wanted to be a foreign journalist.I took courses in weather science at Eastern Kentucky University, but I majored in broadcasting news.

How did you finally become a weatherman?

My first job in the early 80’s was at the local TV station in Paducah, Kentucky.I did everything from turning on the lights in the morning to writing and delivering morning news.I put together weather forecasts, and became interested in them.

Back then, how did you forecast weather?

Independent companies collected computer information that showed, for example, how a single weather system might split into snow or snow mixed with rain.The information was often opposite and the job of a weatherman was to study the information and make the best educated guess about the storm.

Has weather forecasting changed much with new technology?

Advanced computers, satellites, and Doppler radar (sound waves used to track storms) have made forecasting more exact.But we still know very little about how weather is shaped.So far, we just have theories.

Any advice for children who’d like to become weather scientists?

To me, weather is the most exciting field in the world.There are still so many more questions about weather than answers.After all, if we can’t foresee floods or hurricanes, how safe a society are we? Weather forecasting is wide open for scientists who love to solve puzzling problems.The next generation of meteorologists (weather scientists) will unlock many of Earth’s weather secrets.So get a general knowledge of Earth science, and study meteorology (weather science) in college.

Thanks, Sam.                                

1.Judging from the writing style, the text is ________.

A.a diary   B.an interview     C.a news story     D.an announcement

2.As a child, ABC-TV’s Sam Champion wanted to be a ________.

A.space scientist  B.weatherman     C.news reporter   D.meteorologist

3.Present weather forecasting technology ________.

A.has made weather report more exact than ever            

B.is still not perfect

C.hasn’t changed much in the last 50 years                           

D.both A and B

4.The study of weather science is called ________.

A. meteorology   B. forecasting    C .geography      D. earth science

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如图所示,理想变压器原、副线圈的匝数比为10:1,b是原线圈的中心接头,电压表V和电流表A均为理想电表.从某时刻开始在原线圈c、d两端加上交变电压,其瞬时值表达式为u=220sin100πt(V).下列说法正确的是(  )

A.当单刀双掷开关与a连接时,电压表的示数为22V

B.当单刀双掷开关与b连接时,电压表的示数为11V

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D.单刀掷开关由a扳向b时(滑动变阻器触头P不动),电压表和电流表的示数均变大

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下列哪项情况符合食品添加剂带入原则()

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B、食品配料中该添加剂的用量不应超过允许的最大使用量;

C、应在正常生产工艺条件下使用这些配料,并且食品中该添加剂的含量不应超过由配料带入的水平;

D、由配料带入食品中的该添加剂的含量应明显低于直接将其添加到该食品中通常所需要的水平。

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