问题 探究题

在“探究凸透镜成像规律”的实验中,将发光体S(箭头形状的发光二极管,长为2cm)、凸透镜T、光屏P安装在光具座上进行试验,如图所示。

固定凸透镜T,将发光体S放在离凸透镜4cm(物距)处,移动光屏P,如果找不到像,则记录光屏上光斑的特征;如果在光屏上出现清晰的像,则记下像的特征,测出光屏P到透镜T的距离(像距)和像的长度。然后,将物距依次增加2cm,重复上面的实验。实验数据如下表,根据表中的信息,回答下列问题:

(1)凸透镜T的焦距为_______________cm。

(2)物距在_____________范围时,在光屏上总成倒立放大的实像。

(3)当物距从开始再到逐渐增大时,则像的大小______________,像距_____________。(均选填“变大”、“变小”、“不变”、“先变小后变大”、“先变大后边小”)

(4)当物距等于7cm时,物体在光屏上_____________成像(填“一定会”、“一定不会”“可能会”)。分析表中成倒立实像的实验数据,当物像间距(+)最小时,成在光屏上的像的长度__ ______________发光体的长度。(填“大于”、“小于”或“等于”)。

(5)请你根据下表提供的信息,再找出一条规律________________________。

答案

(1) 8

(2) 大于8cm小于16cm(或大于10cm小于16cm、或大于f小于2 f)

(3) 变小;变小

(4)一定不会;等于

(5) 如:>8cm成实像;<8cm成虚像;>16cm成倒立缩小实像等;物像间距与像的大小之间的规律等(合理即可)

阅读理解

阅读理解。

     When my family moved to America from a small village in Guangdong, China, we brought not only our

luggage, but also our village rules, customs and culture. One of the rules is that young people should

always respect elders. Unluckily, this rule led to my very first embarrassment in the United States.

     I had a part-time job as a waiter in a Chinese restaurant. One time, when I was serving food to a

middle-aged couple, the wife asked me how the food could be served so quickly. I told her that I had

made sure they got their food quickly because I always respect the elderly. As soon as I said that, her

face showed great displeasure. My manager, who happened to hear what I said, took me aside and gave me a long lecture about how sensitive (敏感) Americans are and how they dislike the description "old". I

then walked back to the table and apologized to the wife. After the couple heard my reason, they

understood that the problem was caused by cultural differences, so they laughed and were no longer

angry.

     In my village in China, people are proud of being old. Not so many people live to be seventy or

eighty, and people who reach such an age have the most knowledge and experience. Young people

always respect older people because they know they can learn from their rich experience.

     However, in the United States, people think "growing old" is a problem since "old" shows that a

person is going to retire or that the body is not working well. Here many people try to keep themselves

away from growing old by doing exercises or jogging, and women put on makeup, hoping to look young. When I told the couple in the restaurant that I respect the elderly, they got angry because this caused

them to feel they had failed to stay young. I had told them something they didn't want to hear.

     After that, I changed the way I had been with older people. It is not that I don't respect them any

more; I still respect them, but now I don't show my feelings through words.

1. Jack brought the couple their food very fast because        .

A. the manager asked him to do so    

B. he respected the elderly

C. the couple wanted him to do so    

D. he wanted more pay

2. When Jack called the couple "elderly", they became        .

A. nervous

B. satisfied      

C. unhappy

D. excited

3. In Jack's hometown,        .

A. people dislike being called "old"      

B. people are proud of being old

C. many people reach the age of seventy or eighty

D. the elderly are the first to get food in restaurants

4. After this experience, Jack        .

A. lost his job in the restaurant      

B. made friends with the couple

C. no longer respected the elderly      

D. changed his way with older people

5. Which of the following is TRUE?

A. The more Jack explained, the angrier the couple got.

B. Jack wanted to show his feelings through words after his experience.

C. The manager went back to the table and apologized to the couple.

D. From this experience, Jack learned more about American culture.

问答题 简答题