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

题型:选择题

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
题型:选择题

Chicago  On  a  Budget

How to have fun in Chicago without spending a lot of money?

Sightseeing

○ The Art Institute of Chicago has a fine collection of photos and paintings. The ticket is $10.00,but go on Tuesdays and you’ll get in free(免费).

○ The Sears Tower is the world’s third tallest building. By going to the 103rd floor, you can get a great view of the whole city! All for only $8.50.

○ There are free concerts in Grant Park in summer. They are held Wednesday through Saturday night at 7:30 p.m.

○ Attend the taping of a TV show for free. The Oprah Winfrey Show and The Jenny Jones Show both offer tourists free tickets. For The Oprah Winfrey Show you’ll have to book tickets at least a month before.

Places to stay

You can get a hotel for $100 to $ 300 a day. However, you can get a room in the dormitory(宿舍) at Roosevelt University for $215 for a whole week! But you have to stay for 30 days to get this great rate(优惠).

小题1:This passage is written for telling us ___________.

A.Chicago is a big and beautiful city

B.where we can see fine photos and paintings

C.how to make a cheap trip in Chicago

D.there are many free concerts in Chicago小题2:It will cost you _________ if you visit the Art Institute instead of the Sears Tower on Sundays.

A.more

B.less

C.the same

D.none小题3:You may go to ________ if you like to get a great view of the whole city.

A.the Art Institute

B.the Sears Tower

C.Roosevelt University

D.Grant Park小题4:You have to spend at least _____________in all to stay in a dormitory room at Roosevelt University at a good rate.

A.$100

B.$300

C.$215

D.$860小题5:According to this passage, which of the following statements in NOT TRUE ?

A.You are free to go to the Art Institute on Tuesdays.

B.Free Grant Park concerts are held four nights a week in summer.

C.The Sears Tower is the world’s third tallest building.

D.You can get tickets to The Oprah Winfrey as soon as you arrive.

题型:选择题

自动分析仪中采用“顺序分析”原理的是()。

A.分立式自动生化分析仪

B.干化学式自动生化分析仪

C.离心式自动生化分析仪

D.连续流动式自动生化分析仪

E.高效液相色谱仪

题型:选择题

某医院为验证某药品的疗效,对其进行了双盲实验,双盲实验的主要目的是()

A、使研究更合乎道德 

B、减少抽样误差的影响 

C、尽可能减少退出和失访的人群 

D、使对比组间人口特征和临床特征有可比性 

E、尽可能减少来自研究者和受试者的主观偏倚

题型:选择题

用滤纸过滤时,玻璃棒下端(),并尽可能接近滤纸。

A、对着一层滤纸的一边

B、对着滤纸的锥顶

C、对着三层滤纸的一边

D、对着滤纸的边缘

题型:选择题

经过人们的长期研究已经确定,金属与电解液作用所发生的腐蚀,是由于金属表面发生()而引起的。因此,这一类腐蚀,通常叫做电化学腐蚀。

A.微电池

B.原电池

C.电极电位

D.干电池

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