题干

如图所示,一束白光斜射入半圆形的玻璃砖的圆心,通过玻璃砖后有ab两条光线,可知(   )

A:在玻璃中,a光的传播速度小于b光的传播速度

B:在真空中,a光的波长小于b光的波长

C:玻璃砖对a光的折射率小于对b光的折射率

D:若改变光束的入射方向使θ角逐渐增大,则折射光线a首先消失

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答案(点此获取答案解析)

A,B,D

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    Which boy hasn't dreamed of being a cool secret agent (特工)? The wonderful fighting abilities and the world-saving adventures are much more colorful than most people's everyday lives. Well, Cody Banks is just like any other boy, except that he is not just dreaming. He has a big secret his friends never know about. He was trained to be a spy (间谍)by a special CIA programme, which was made to look like a summer camp. He learned high-speed driving, hand-to-hand fighting and the use of high-tech tools.

    After proving he could become a young hero by saving a baby from a runaway car, Banks gets his first real task. He must make friends with a popular girl at school, Natalie Connors. Then, he must spy on her father, a scientist who has developed a dangerous technology (技术).Banks must stop a group of bad people from forcing Natalie's father into using the technology to endanger the world.

    The CIA may have taught him first-class self-defense moves, but they didn't show him how to talk to girls. Banks has zero ability when it comes to dealing with girls. How can he get around his problem and get an invitation to the girl's upcoming birthday party? Will he finally become Natalie's boyfriend and find out whatever he can about her father's work?

    Agent Cody Banks has everything that young people are interested in: big explosions, breath-taking performances and funny girl-dating experiences. It was listed No.2 in the American box office last week.

    “This story is interesting and fun for the whole family to enjoy, and especially cool for young boys,” said Paul Perkins, a film reviewer in the US.