问题 选择题

只含有ab两种单色光的复色光由某种介质射向真空,光路如图所示,则下列说法正确的是

A.a光在玻璃砖中的传播速度比b光小

B.a光的频率比b光小

C.a光的临界角比b光小

D.ab通过相同的双缝干涉实验装置,a光的条纹间距比b光大

答案

BD

:由光路图可知,b光折射率大,a光在玻璃砖中的传播速度比b光大,a光的频率比b光小,选项A错误B正确;由全反射临界角公式可知,a光的临界角比b光大,选项C错误;由双缝干涉条纹间隔公式,ab通过相同的双缝干涉实验装置,a光的条纹间距比b光大,选项D正确。

阅读理解

阅读理解。

     Lily has a penfriend in America. Her name is Alice. They write to each other every week. They tell each

other about their lives. Here is a letter from Lily.

Dear Alice,

    Thank you for your letter and telling me about your best friend.In this letter,I'm going to tell you about my

friend.Her name is Cathy. She has long brown hair and blue eyes. She is the same age as me,but a little taller.

She is always happy. We sit together in class and help each other with our homework. We always play

together after school and play computer games for an hour. Cathy thinks quickly (迅速地) and does better

than me. She is learning to play the piano (钢琴).I am learning to play the piano,too.We play together every

day. It's fun. We always have a good time.

     Please write to me soon. 

                                                                                                                                                   Love, 

                                                                                                                                                   Lily

1. How often does Lily write to Alice? [ ]

A. Every two weeks.

B. Every week.

C. Every day.

D. Every three weeks.

2. Who is Lily's best friend? [ ]

A. She doesn't have one.

B. Cathy.

C. Alice.

D. Tommy.

3. What is Cathy's hair like? [ ]

A. Long and green.

B. Long and brown.

C. Short and brown.

D. Short and black.

4. When do they play computer games? [ ]

A. Before school.

B. At school.

C. After school.

D. At the weekend.

5. What other things do they do together every day? [ ]

A. Write letters.

B. Sing.

C. Play the piano.

D. Use the computer.

填空题