问题 不定项选择

如图,空间某区域中有一匀强磁场,磁感应强度方向水平,且垂直于纸面向里,磁场上边界b和下边界d水平。在竖直面内有一矩形金属线圈,线圈上下边的距离很短,下边水平。线圈从水平面a开始下落。已知磁场上下边界之间的距离大于水平面a、b之间的距离。若线圈下边刚通过水平面b、c(位于磁场中)和d时,线圈所受到的磁场力的大小分别为Fb、Fc和Fd,则

[ ]

A.Fd>Fc>Fb      

B.Fc<Fd<Fb

C.Fc>Fb>Fd

D.Fc<Fb<Fd

答案

答案:D

阅读理解

阅读理解。

     Around 200 people who thought their only experience of the London 2012 Olympic Games would

be minor heats of synchronized swimming (花样游泳) have received an unexpected change to the

men's 100m final because of an embarrassing ticketing mistake.

     The London 2012 Organizing Committee (Locog) confirmed on Wednesday that an error in its

ticket selling had led to four synchronized swimming competitions being oversold by 10, 000 tickets.

     Locog and its ticket agent spent the Christmas period contacting ticket holders and offering them

alternatives that included the tickets they had applied for but unsuccessful. The changes need no additional cost. It has also offered to return any discrepancy (差额) if the new tickets cost less than the originals. Locog said the replacement tickets would come from a number of unsold seats across the Olympic

Games and that it was doing all it could to make up the error to the fans who bought tickets.

     Locog said the error occurred in the summer, between the first and second round of ticket sales,

when a member of staff made a mistake, entering “20,000” into the computer rather than the correct

figure of 10,000 remaining tickets. The error was discovered when Locog checked the number of tickets

that had been sold against the final seating numbers, and began contacting ticket holders before Christmas.

     Thousands of ticket holders have already struck lucky, changing to tickets for major events including

swimming and athletics finals, and in around 200 cases the hottest of all, the men’s 100m final. Locog said

the decision to award 100m final tickets was made because one of the synchronized swimming

competitions was on the same afternoon as the event, August 5.

1. As a result of the ticketing mistake, about 200 people ____.

A. will luckily be able to watch the men’s 100m final

B. will not enjoy the synchronized swimming events

C. will have to change their tickets to other games

D. have applied for tickets to the men’s 100m final

2. In order to solve the problem, the Locog ____.

A. required the holders to return the tickets

B. allowed the holders to apply for another ticket

C. would charge the discrepancy for changing the tickets

D. offered to change the tickets without any extra cost

3. The underlined word “it” (Paragraph 3 ) refers to ____.

A. Locog                        

B. the ticketing mistake

C. the Olympic Games            

D. the additional cost

4. How many ticket holders will have to change their tickets?

A. 200.      

B. 10,000.        

C. 20,000.        

D. 30,000.

5. Which of the following is true according to the text?

A. The synchronized swimming is the hottest of the Olympics.

B. Thousands of ticket holders refused to change their tickets.

C. The men’s 100m final will take place on August 5, 2012.

D. The number of tickets for synchronized swimming is 10,000.

单项选择题