问题 探究题

教学中常用的投影仪结构如图甲所示,在水平放置的凸透镜的正上方有一与水平面成45°角的平面镜,右边竖直放一屏幕,物体的光线经凸透镜和平面镜后,可在屏上成一清晰的像,图乙是这一装置的示意图,A''B''是物体AB的像,图中BO1=30 cm,O1O2=20 cm,O2O3=90 cm。

(1)对凸透镜而言,物距和像距各为多少?

(2)在图乙中画出物体AB的成像光线图;

(3)若将凸透镜上移一点,像将向何方移动?

(4)说明螺纹透镜的作用。

答案

(1) u=30 cm,υ=110 cm

(2)作图如图所示

(3)凸透镜向上移,相当于物距增大,则像距必减少;则A'B'下移,则A''B''必左移

(4)螺纹透镜可对光源发出的光起会聚作用,能扩大聚光面积使像更清晰,它对光的会聚作用与凸透镜相同,但却薄得多,轻便得多

阅读理解

阅读理解

                                                     Summer Holiday Fun 2010!

     The summer holidays are upon us again.Here is our guide to summer holiday fun in Peterborough!

     Peterborough Museum

     The Age of the Dinosaurs is the museum's main attraction this summer.Get up close to prehistoric

creatures via some great handson exhibits!Watch out for monsters lurking around every ember!The

museum is open from 10?00 am to 5?00 pm Monday to Saturday, and from 12?00 pm to 4?00 pm on

Sundays in August.

     Call 01733 864663 for details.

     Saxon Youth Club

     School holiday fun:Young people aged 13~19 will be able to produce their own music, compete in

sports activities, or try their hand at cooking at Saxon Youth Club, Saxon Community Centre, Norman

Road, Peterborough every Monday and Wednesday from 3?00 pm.PLUS an aeroball tournament will

take place on Thursday,12th August between 3?30 pm and 6?30 pm.

     Call 01353 720274 for details.

     Houghton Mill

    Through the Looking Glass-a new production of the family favorite on Monday 30th, August.Bring

rugs or chairs to sit on and a picnic if you wish to eat during the play.Gates open 5∶30 pm,

performance 6∶30 pm~8∶30 pm.Tea room will be open until the end of the interval.Adult £10.

Child £7.Family £20.

      Booking advisable on 0845 4505157.

     Farmland Museum and Denny Abbey

     Farmland Games:From Wellie Wanging to Pretend Ploughing matches, come and join the Farmland

Team.Collect your sporting stickers and create a colorful rosette that is fit for a winner!No need to book,

just turn up between 12?00 pm and 4?00 pm on Thursday,19th August.Suitable for children aged four

and above, each child should be accompanied by an adult and all activities are included in the normal

admission price.Tickets Cost:£7 per child.

      For further information, call 01223 810080.

1. If you are interested in cooking, you can go to________.

A. Peterborough Museum  

B. Houghton Mill

C. Saxon Youth Club  

D. Farmland Museum

2. You want to watch the new play with your parents, so it will cost you________.

A. £7  

B. £17  

C. £27  

D. £20

3. Which of the following activities needs parents' company?

A. Playing farmland games.

B. Watching the new play.

C. Competing in sports activities.

D. Visiting the dinosaur exhibition.

4. If Tom comes to Peterborough Museum on August 19, he will have________to choose from for

   himself.

A. one activity  

B. two activities

C. three activities  

D. four activities

单项选择题