问题 填空题

某班同学在“探究凸透镜成像规律”的实验中,记录并绘制了物体到凸透镜的距离u跟像到凸透镜的距离v之间关系的图象,如图所示,则该凸透镜的焦距是______cm,当u=15cm时,在光屏上能得到一个倒立、______的实像,______(照相机/幻灯机/放大镜)就是用此原理制成的.

答案

由图知,当物距等于20cm时,像距等于20cm,所以此时成倒立等大的实像,物距等于像距等于2f.

所以f=10cm,当物距等于15cm时,物距处于f和2f之间,此时成倒立放大的实像.幻灯机和投影仪是根据这个原理制成的.

故答案为:10;放大;幻灯机.

单项选择题
阅读理解

A spirit of adventure, curiosity about different cultures and the desire for a challenge can be found in young people everywhere. More and more students in China are backpacking around the country.

According to the China Youth Travel Service, Hainan, Dalian, Zhangjiajie and Qingdao were among the most popular spots for young Chinese backpackers last year. Backpacking allows the traveler a greater sense of independence.

“I can no longer put up with the instructions of a tourist guide,” said Huang Ye, a 19-year-old college student in Beijing. “They are always driving you to places that you do not want to go to and trying to make you buy local souvenirs(纪念品).”

Huang likes to travel as a backpacker. She prefers an independent trip that she took with two friends to Jiuzhaigou in Sichuan Province. There, they chose some scenic spots to visit and avoided the masses of tourists.

Backpackers see the difficulties of such travel as a challenge. Living on bread and water for days on end, wearing the same clothes over and over again and carrying a heavy bag on their backs while climbing a mountain are all character-building experiences.

But perhaps the greatest challenge that a backpacker faces is not a physical one, but mental. They may face loneliness if they travel alone.

Chen Xuewei, 21, suffered when he took off around China last year. “I felt very lonely at the beginning of my journey. A walkman didn’t make me feel better, but rather heightened the sense of loneliness I felt. I even called up my friends to tell them that I wanted to give up and go back to Beijing,” he recalled. But he kept going. He started to make friends and appreciate the local customs. He took lots of photos to record his trip and now he is glad he stuck it out.

Backpackers generally find themselves to be mature(成熟)after their experiences. “Their travel logs(旅行日志)track their development as people.” “When I feel frustrated, I read my travel log again,” said Tang Weifeng, a postgraduate at Peking University. “By reading it, I get a sense that I am better off now than I was when I wrote those words by the light of a torch in a hot tent.”

63. Which of the following is NOT mentioned as one of the advantages of backpacking according to the story?

A. It builds up your character.

B. Through the experience, you learn to live in a tent.

C. Through the experience, you learn to rely on yourself.

D. Through the experience, you learn to deal with loneliness.

64. What does the underlined word “frustrated” in the last paragraph mean?

A. Disappointed.       B. Happy.       C. Tired.       D. Excited.

65. What is the story mainly about?

A. Some backpackers’ experiences.  

B. The advantages of backpacking.

C. Young people’s love of backpacking.

D. The increasing popularity of backpacking among Chinese students and its reasons.