问题 填空题

如图所示,光线由空气射入玻璃砖,玻璃砖的AC.BD两个端面与AB.CD面垂直,入射点O的位置不变,入射光线的方向可以任意变化.下列说法正确的是

A.光线在AB界面上不可能出现全反射

B.光线在CD界面上不可能出现全反射

C.光线在BD界面上可能出现全反射

D.光线在BD界面上不可能出现全反射

答案

ABC

发生全反射现象的条件是:光从光密介质射向光疏介质,入射角大于等于临界角.现光线从空气射向玻璃砖,玻璃对空气来说是光密介质,因此在AB界面上不可能发生全反射现象.入射光进入玻璃砖后发生折射现象,偏折情况如图所示.折射光线入射到BD的分界面上,这时的入射角α可能大于临界角,则在BD的分界面上有可能发生全反射现象.

若折射光线OEBD界面上发生全反射现象,反射光线EF入射到CD分界面上,入射角等于r,而r是小于临界角的.这一点从入射到AB界面上入射光线及其折射光线OE的关系上可得以说明.因为入射角i小于90°,所以折射角r小于临界角C.因此在CD界面上不可能发生全反射现象.

本题考查学生对发生全反射现象条件的掌握,以及发生全反射的条件的分析判断.

全反射现象发生的条件是光线由光密介质射入光疏介质且入射角大于临界角.当入射角等于临界角时,折射角应等于90°;当入射角小于临界角,不发生全反射现象,此时折射角小于90°.根据光路可逆原理,若光线从光疏介质射入光密介质,且入射角小于90°,则此时的折射角也一定小于临界角,由此判断出该题中r小于临界角是本题的关键.

单项选择题 B型题
阅读理解

阅读理解。

     When I first heard that Zhang Yimou, China's leading director most well-known for Hero in the West,

a question immediately came into my mind: Would A Simple Noodle Story be directed by the good Zhang

Yimou or the bad Zhang Yimou? The answer:neither.

     Starting with his first time as a cinema-photographer on Yellow Earth right after graduating from film

school in the early 80s, everything Zhang shot was inspiring. In the late 80s and early 90s, he directed

several movies already considered classics, including the banned (禁止) To Live.

     A Simple Noodle Story is set in the late Ming Dynasty (1368~1644), follows several amusing characters

working in a restaurant in the faraway, but naturally beautiful, western province of Gansu. Zhang brought

together a group of popular comedic (喜剧的) actors led by Xiao Shenyang, who shot to fame earlier last

year because of his very funny styles. Xiao Shenyang's character, Li Si, is having an affair with his boss's

wife, who is simply called "Boss' Wife" throughout the movie.

     A Simple Noodle Story, which started national screening Friday, is already bringing in money, scoring

a total box office income of 67.1 million yuan? ($9.83 million) by Sunday morning and is expecting its first

weekend to reach 100 million yuan ($14.65 million).

     In spite of the box office success, the film has received mixed reviews. Most local media admitted Zhang's

success in entertaining the public, but writer Han Han wrote in his blog that A Simple Noodle Story is more

like a long-drawn-out TV comedy and that Zhang has made no improvement in directing since his first film.

     In his defense, Zhang said that he was just trying to have fun with the film. "I'm not a master of artistic

films. I am just trying to make a fun movie."

1. Which part of the newspaper do you think the passage choose from? [ ]

A. Sports

B. Politics

C. Entertainment

D. Economy

2. Which of the following can be the best title of the passage? [ ]

A. A Famous Film Director -Zhang Yimou

B. Good Zhang Yimou or Bad Zhang Yimou?

C. A Simple Noodle Story

D. Zhang Yimou with His New Movie Has Come Again

3. What is the meaning of the underlined phrase "box office" in paragraph 5?

A. 售票处

B. 票房成绩

C. 影院包厢

D. 影院办公室

4. From this passage we can guess what kind of film "A Simple Noodle Story" belongs to? [ ]

A. An artistic film

B. A film about photographs

C. A classic film

D. A comedic film.