问题 问答题

“十一”去无锡市旅游的小明站在同一位置用数码相机(焦距可改变)对着无锡著名景点——锡山先后拍摄了两张照片甲和乙,如图所示。他产生了这样的疑问:物体通过凸透镜在光屏上所成像的大小与透镜的焦距有何关系呢?小明对此进行了探究。

(1)小明找来了一些凸透镜,但不知道它们的焦距,请你为他提供一种测量透镜焦距的方法。(可画图说明,4分)

(2)测出凸透镜焦距后,小明先后选用了三个焦距分别为15cm、10cm、5cm的凸透镜,在保持物距始终为35cm的情况下依次进行实验,发现所成的像越来越小。请根据实验结果判断小明在拍摄哪一张照片时照相机镜头的焦距较大。

答:拍摄      照片时照相机镜头的焦距较大。(3分)

(3)在探究过程中,小明总是让物距保持不变,请你说出他这样做的理由。(3分)

答案

(1)略   (2)乙  (3)控制变量,u不变时,才能得到像的大小与焦距的关系

(1)凸透镜正对阳光,光线平行于凸透镜的主光轴,经凸透镜会聚在主光轴上最小、最亮的点,该点是凸透镜的焦点,在焦点左右的光点不是最小最亮的,测量的焦距偏大或偏小;(2)根据像的大小和凸透镜焦距的关系:物距一定时,焦距越小,像越小.甲和乙两张照片中,乙照片上锡山的像比较大,照相机镜头的焦距较大.(3)因为像的大小与物距和焦距都有关系,根据控制变量法,探究像的大小与焦距的关系,应保持物距不变,改变焦距,观察像的大小变化.

阅读理解

阅读理解。

     Many people hate the idea of having to sleep on a plane. But Swedish entrepreneur Oscar Dios thinks

they can be persuaded otherwise and he has created a new kind of hostel to prove it.

     Dios says it is the world's first jumbo jet hostel, an actual jet-plane Sweden's main airport outside

Stockholm which has been converted (改装) into a 25-room guesthouse that sleeps as many as 72 people.

     "I learned about this plane that was standing abandoned at Arlanda airport and I've been trying the concept

of hostels in many different houses and buildings," he told reporters. "I thought, 'Why not a plane?'" 

     Jumbo Hostels opened for business on Thursday, giving customers the chance to check in and sleep in

a room that can best be described as cozy.

     "The most challenging part with this project is trying to build something inside a metal hull (外壳)-it's just

really, really tight."

     The jet, which was originally produced for Singapore Airlines, was taken out of service in 2002. One thing

the hostel has going for it is price-a room starts at 350 Swedish crowns (about $ 41), which is a lot less than

hotel rooms outside of major airports.

     Another feature: customers can get married on the wing of the plane and live in the plane's more luxurious

honeymoon room situated in the cockpit (驾驶舱).

     Instead of walking down the aisle (走廊), lovebirds can take what Jumbo Hostels calls the "wing walk,"

where they can be joined in great joy at the wing tip. The hostel has someone ready to perform the ceremony.

     But in some respects, this hostel remains a plane-most customers have to share the jet's nine bathrooms

and staff only wear air steward and stewardess clothes. The only room that has its own bathroom is the

honeymoon suite.

1. Swedish entrepreneur Oscar Dios creates a new kind of jet hostel in order to _____. [ ]

A. make people more comfortable

B. earn more money from people

C. change people's idea of not sleeping on the plane

D. explore the sources of the universe

2. According to the passage the jet hostel is _____. [ ]

A flying in the sky

B. hung in the sky

C. lying on the airport

D. buried underground

3. The advantages of the jet hostel are the following EXCEPT _____. [ ]

A. more comfortable

B. suitable for new couples

C. convenient bathroom

D. cheaper

4. This abandoned plane originally belongs to _____. [ ]

A. Stockholm Airlines 

B. Singapore Airlines

C. Sweden Airlines

D. Oscar Dios Airlines

5. Which statement of the following do you think can best describe this passage? [ ]

A. A new fashion of wedding in the plane.

B. For travelers, a new way to get a restful night.

C. A new way to enjoy yourselves.

D. How to change a plane into a hostel.

多项选择题