如图所示为用某种透明材料制成的一块柱体形棱镜的水平截面图,FD为圆周,圆心为O,

题型:计算题

问题:

如图所示为用某种透明材料制成的一块柱体形棱镜的水平截面图,FD为圆周,圆心为O,光线从AB面入射,入射角θ1=60°,它射入棱镜后射在BF面上的O点并恰好不从BF面射出.

(1)画出光路图;

(2)求该棱镜的折射率n.

考点:光的折射定律
题型:计算题

阅读理解。

     Prana was a beautiful dog, whose name means  "breath  of life". Although he died several years ago, I

can still remember the days we spent together and what he has taught me about love.

     I have two apple trees in the garden. Prana loved apples.  When he went outside, he'd catch an apple

and take it into the house to eat later.  The apples had been on the ground and were often dirty so I

wasn't always happy that Prana had brought them into the house.

     It was an autumn day in America, but it was very cold  A big snow fell and we had not done anything

for its coming.  On  that  special   day,   Prana  went  outside and I watched  him through the window.  I

noticed that he was madly digging (挖) holes and bringing the apples to the ground so they could be seen

above the snow. I did not know why he was doing this. He seemed to want to do something special.       .

     When I called him back, he had his usual  one  apple  in  his mouth. About five minutes later, I looked

outside.  The garden was completely covered with birds.  Prana  had  dug up all those apples for his bird

friends to eat. He knew that they wouldn't have stored enough food for the coming winter!

1. Prana was__________.                      

A. the writer                

B. a boy

C. a bird                    

D. a dog

2. I wasn't always happy because_________.

A. Prana loved apples

B. Prana caught an apple and ate it

C. `the apples fell on the ground and were dirty

D. Prana brought the dirty apples into the house            

3. On the snowy day, Prana ___________.

A. ate up all the apples

B. dug holes to put the apples in them

C. brought the apples under the snow to the ground

D. left the house and died

4. The birds flew to the garden to ____________.

A. look for Prana

B. eat the apples

C. make new homes

D. store food for the winter

5. The topic of the story is about ___________.        

A. apples              

B. animals

C. love                

D.life

题型:计算题

(1).()有效成分尚未清楚的方剂粗提宜采取的提取方法为
(2).()挥发性成分含量较高的方剂宜采取的提取方法为
(3).()挥发性成分、水溶性成分为有效成分的方剂宜采取的提取方法为
(4).()无组织结构,新鲜药材宜采取的提取方法为

A.煎煮法

B.浸渍法

C.渗漉法

D.双提法

题型:计算题

对蒸发器的维护有何要求?

题型:计算题

在吸取大气中的热量方面,甲烷被认为是二氧化碳的()多倍。

A.5

B.10

C.15

D.20

题型:计算题

消防常用金属切割机是采用()二冲程汽油发动机带动砂轮片高速运转。

A.单缸

B.双缸

C.三缸

D.四缸

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