问题 实验题

探究凸透镜成像规律:

(1)实验中出现了如图所示的情形,要使像成在光屏中央,应将光屏向____________(上/下)调整。

(2)已知凸透镜焦距为10cm,将烛焰放在距离凸透镜25cm处,调节光屏可得到倒立、____________(放大/缩小/等大)的实像,应用这个原理工件的仪器有____________。

(3)在上述实验的基础上,将蜡烛向远离透镜的方向移动,要在光屏上得到清晰的像则应将光屏____________(远离/靠近)透镜,光屏上的像____________(变大/变小/不变)

答案

(1)下

(2)缩小; 照相机  

(3)靠近 ;变小

单项选择题
阅读理解

阅读理解

     Do you always forget where you placed your keys or your purse? What was the name of the movie

you saw last week? The major cause of your forgetfulness may be linked to what you store in your body,

not in your short-term memory bank.

     Tests continue to show that people with enough Vitamin B-2 do well in memory exams. The "B"

could stand for "brain", if you're one of many with limited instant recall. And the number one source of

that vitamin is sunflower seeds.

     Even when you're sleeping or relaxing, your brain is still at work. Although it makes up just two

percent of your total body weight, it uses up to 30 % of the calories you take in each day. For it to work

properly, it must be fed. Even if you're not a breakfast eater, that meal is the best way to prepare your

brain for the day. A quick and easy English muffin with peanut and butter in it, a glass of milk, and an

orange, might be what your brain may be asking you the first thing in the morning when you feel your head

is in a fog. Having sunflower seeds and fruit between meals adds more muscle to that hungry, demanding

organ. Vitamin B-1 also helps the memory, and that is found in eggs, meats and nuts. In Chinese culture,

walnuts (核桃) are known as the fruit for a long life because it is believed that they feed both the kidneys

and the brain. And accor ding to Chinese culture, if you keep those two important organs in good working order, you'll live longer.

     However forgetful you are, just keep in mind the letter "B", which will help you to "bear in mind almost everything" even on those days when life's challenges are sending you in a billion directions.

1. The underlined word "muffin" in the third paragraph probably means_________.

A. menu          

B. dinner          

C. calorie          

D. cookie

2. In the passage, Chinese culture is mentioned to____________.

A. support the idea of long life       

B. show the importance of vitamin B-1  

C. warn the readers of two organs      

D. remind us of walnuts and sunflower seeds

3. What can we conclude from the passage?

A. What we eat seems more important than what we learn in terms of memory.  

B. Two percent of our brain is still active when we are sleeping or relaxing.

C. It doesn't make much difference to our brain whether we have breakfast or not.  

D. Life's challenges have no effect on our memory, if dealt with in a proper way.

4. The best title for the passage could be_______________.

A. Human of Memory Loss              

B. Vitamin B-2 and Memory

C. Forgetful? But not Brain             

D. Chinese Culture of Long Life