如图电路,R1=2欧,R2=4欧,电源电压6伏,闭合开关S,通过R1的电流为__

题型:填空题

问题:

如图电路,R1=2欧,R2=4欧,电源电压6伏,闭合开关S,通过R1的电流为______安,电压表示数是______伏.

考点:电阻的串联欧姆定律及其应用
题型:填空题

如图所示,请根据电路图,用两根导线把图中电路元件连接成相应的电路。

题型:填空题

                                                        Heroes of Our Time      

A good heart

    Dikembe Mutombo grew up in Africa among great poverty anddisease. He came to Georgetown

University on a scholarship(奖学金)to study medicine一but Coach(教练)John Thompson got alook

at Dikembe and had a different idea. Dikembe became a star inthe NBA,and a citizen of the United

States. But he never forgot the1and of his birth, or the duty to share his fortune with others. Hebuilt

a new hospital in his old hometown in the Congo. A friend hassaid of this good-hearted man:"Mutombo

believes that God hasgiven him this chance to do great things. "Success and kindness

    After her daughter was born, Julie Aigner-Clark searched forways to share her love of music and

art with her child. So she borrowed some equipment, and began filming children's videos in her own

house. The Baby Einsteln Company was born, and in justfive years her business grew to more than

$20 million in sales. Andshe is using her success to help others-producing child safety videos with

John Walsh of the National Center for Missing and Exploited Children. Julie says of her new program:

"I believe it's the most important thing that I have ever done.I believe that childrenhave the right to live

in a world that is safe. "Bravery and courage

     A few weeks ago, Wesley Autrey was waiting at a Harlemsubway station with his two little girls

when he saw a man fall in to the path of a train. With seconds to act, Wesley jumped onto thetracks,

pulled the man into the space between the rails(铁轨),andheld him as the train passed right above

their heads.

     He insists he's not a hero. He says,"We have got to show each other some love. "

1. What was Mutombo praised for? 

A. Being a star in the NBA.

B. Being a student of medicine.

C. His work in the church.

D. His willingness to help the needy.

2. Mutombo believes that building the new hospital is___________. 

A. helpful to his personal development

B. something he should do for his homeland

C. a chance for his friends to share his money

D. a way of showing his respect to the NBA

3. What did the Baby Einstein Company do at its beginning?

A. Produce safety equipment for children.

B. Make videos to help protect children.

C. Sell children's music and artwrork.

D. Look for missing and exploited children.

4. Why was Wesley Autrey praisied as a hero? 

A. He helped a man get across the rails.

B. He stopped a man from destroying the rails.

C. He protected two little girls from getting hurt.

D. He saved a person without considering his own safety.

题型:填空题
如图所示,矩形线圈有N匝,长为a,宽为b,每匝线圈电阻为R,从磁感应强度为B的匀强磁场中以速度v匀速拉出来,那么,产生的感应电动势和流经线圈中的感应电流的大小应为(  )

A.E=Bav,

B.E=NBav,

C.E=Bav,

D.E=NBav,

题型:填空题

工作面在回采前必须编制()。

A、采区设计

B、作业规程

C、生产规程

D、生产计划

题型:填空题

机关管理体制的核心问题是()

A.机构构建

B.制度运作

C.权力划分

D.监督到位

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