试题与答案

如图所示,在x轴上方存在着垂直于纸面向里、磁感应强度为B的匀强磁场,一个不计重力

题型:选择题

题目:

如图所示,在x轴上方存在着垂直于纸面向里、磁感应强度为B的匀强磁场,一个不计重力的带电粒子从坐标原点O处以速度v进入磁场,粒子进人磁场时的速度方向垂直于磁场且与x轴正方向成120°角,若粒子穿过y轴正半轴后在磁场中到x轴的最大距离为a,则该粒子的比荷和所带电荷的正负是(  )

A.,正电荷

B.,正电荷

C.,负电荷

D.,负电荷

答案:

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题型:阅读理解
任务型阅读。
     阅读下面的短文,并根据所读内容在文章后表格中的空格里填入最恰当的单词。
     注意:每空一词。

     In the United States, engineering is a profession(职业) that has been historically under the control of
men. Even today, it's still true that few women become civil or chemical or mechanical engineers, but that's
something on www.EngineerGirl.org encouraging girls to change the present situation. Young women who
visit the web site can find out about a great job choice they might not have considered.
     "Women are not well represented in engineering and in engineering education programs and then of
course, down the road, in the engineering workforce. So only about 20 percent of engineering
undergraduate degrees (本科文凭) go to women, and then only about nine percent of working engineers
are women."
     Mary Mattis, the National Academy of Engineering, says "we know from the research that
middle-school girls are at a critical point in their lives, and that it's a time when we need to reach them, so
this website aims to increase their awareness of interesting fields in engineering. On the other hand, it wants
to make them understand what a wonderful productive and exciting job you can have as an engineer."
     Engineering is a demanding course of study-there is a lot of science and math, for many girls and even
boys that can be challenging. But Ms. Mattis says that the EngineerGirl website stresses that engineering
can also be fun and exciting.
     "It's about designing things. It's about changing the world for people. It's about making a difference.
And, in addition, you can make a good living; you can be independent economically by becoming an
engineer. All of those things are messages that girls need to get."
     While most engineers go into traditional fields such as mechanical and electrical engineering, the
EngineerGirl site also emphasizes engineering jobs which are related to other fields such as bio-engineering,
sports engineering and -believe it or not-chocolate engineering.
     Even if you are not a girl in the target(目标) age group, there's a lot of interesting information on the
site, including biographies(自传)of some well-known women engineers.

TitleWebsite(1)______ Girls to Learn Engineering
Present(2)_____ for the engineering profession in the USAThe majority of men take up the profession throughout(3) ______, while only a small number of women work as engineers.
(4)_____ of the website▲To increase young women's(5)_____of interesting fields in engineering.
▲To make them understand what productivity and (6)_____ the job of being engineers can bring them.
(7)___________ of being
 engineers
▲ It can be fun and exciting.
▲ It can(8)_____ the world for people.
▲ You can make a good living.
▲ You can get economic independence by (9) _____ an engineer
Other fields concerning engineeringVarious chances are talked about like bio-engineering and engineering (10) _____ to sports, and even chocolate.

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