如图所示,两根相距为l的平行直导轨ab、cd、b、d间连有一固定电阻R,导轨电阻

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问题:

如图所示,两根相距为l的平行直导轨ab、cd、b、d间连有一固定电阻R,导轨电阻可忽略不计;MN为放在ab和cd上的一导体杆,与ab垂直,其电阻也为R;整个装置处于匀强磁场中,磁感应强度的大小为B,磁场方向垂直于导轨所在平面(指向图中纸面内);现对MN施力使它沿导轨方向以速度v(如图)做匀速运动;令U表示MN两端电压的大小,则(  )

A.U=vBl,流过固定电阻R的感应电流由b到d

B.U=vBl,流过固定电阻R的感应电流由d到b

C.U=vBl,流过固定电阻R的感应电流由b到d

D.U=vBl,流过固定电阻R的感应电流由d到b

考点:右手定则导体切割磁感线时的感应电动势
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Imagine that your hairstyle is important for your future.  For teenage boys in  Papua  New Guinea this is true! The Hulie people believe that beautiful hair shows a man is healthy and strong.. They respect men who wear wigs, so teenage Hulie boys have to grow great hair. With this hair, they make a wig that they can wear every day.

The Hulie live deep in the rain forest of Papua New Guinea.  Before the 1930s, people from the outside world didn't even know about them. Today, there are about 70000 Hulie people,  Most still follow their traditional way of life. The Hulie live in small villages, but families. do not live together. Women and small children live in one house and. men live together in another house.  When boys are eight years old, they have to leave their mothers to live with their fathers.

Some Hulie children go to school to study reading and math.  But after middle school. While teenage girls babysit their younger brothers and sisters, most teenage boys,to wig school.  At wig school, they learn how to grow their hair and how to make wigs. The rules are pretty serious

1 .They cannot run, because their hair can be damaged.

2. They have to stay away from fire.

3. They have to put water on their hair 12 times a day to make it Grow faster.

When a Hulie teen wears his wig for the first time, he shows he is a man now, he can get married. To prepare, boys grow their hair for 18 months or longer. Then they cut it and use their own hair to make a mushroom-shaped wig.  Later they grow their hair again for special wigs. These special wigs are for celebrations and festivals. Hulie men wear their mushroom-shaped wigs every day, but they like to be fashionable, too. To add style, they decorate their wigs with flowers and feathers.

小题1:The article is mainly about________

A. teenage Hulie girls   

B. teenage Hulie boys      

C. Hulie men and women

小题2: People didn't know the Hulie people until the 1930s because______

A.they lived in small villages 

B. there are only 2700Huli people

C. they were hidden in the rain forest

小题3: The underlined phrase "people from the outside world" means______

A. people who don't live in the rain forest  

B. people who follow their old traditions

C. people who do things outside of the forest

小题4:According to the article we can refer that Huli_________

A. teenage boys live with the mothers  

B. teenage girls live with their fathers

C. husbands and wives do not live together

小题5:Hulie boys do not decorate their wigs with_______

A. flowers            B. mushrooms         C. feathers

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0.35里有(  )个百分之一,0.204里有(  )个千分之一。

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抗痨化疗方案的两个阶段包括()。

A.初治与复治阶段

B.初治与继续巩固阶段

C.复治与继续巩固阶段

D.开始强化及继续巩固阶段

E.开始强化与复治阶段

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常规安全检查通常是对作业人员的行为、作业场所的环境条件、生产设备设施等进行的检查。检查效果很大程度上取决于检查人员的个人经验和能力。为了尽量减小检查人员个人因素对检查结果的影响,常采用的方法是( )。

A.作业条件危险性评价法
B.可靠性分析法
C.事故树分析法
D.安全检查表法

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(三)


根据下列条件,回答下列问题:
某企业开发出一种新产品,单位成本为1000元。

如果该企业希望获得20%的利润率,那么该产品定价为( )元,这种定价方法被称为( )。

A.1500,成本导向定价法

B.1200,成本导向定价法

C.1500,竞争导向定价法

D.1200,竞争导向定价法

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