问题 选择题

2011年3月11日,日本特大地震引起核电站的核泄漏,对周边地区造成核污染,其排出的放射性物质中含有铀235 (U)裂变反应后的产物,如:铯137 (Cs)和碘131 (I)0查证资料显示,铯137会发生β衰变,半衰期为30年,同时放出能量为0.66MeV的γ光子,其频率为V1;碘131也会发生β衰变,半衰期为8天,同时放出能量为0.36MeV的γ光子,其频率为v2,下列说法正确的是(  )

A.铀235裂变的方程可能为:

 23592
U+
 10
n→
 13755
Cs+
 8837
Rb+10
 10
n

B.碘131衰变的方程可能为:

 13153
I→
 13152
Te+
 0-1
e

C.若有10个铯137原子核经过30年,剩下5个铯137原子核

D.光子的频率v1:v2=11:6

答案

A、裂变方程前后的质量数不守恒,A错误;

B、衰变方程的电荷数不守恒,B错误;

C、半衰期是大量原子的统计规律,对少量原子没有意义,C错误;

D、光子的能量与频率成正比,所以v1:v2=0.66:0.36=11:6,D正确;

故选D

完形填空
完形填空。
     Good news! A new educational CD-ROM called "Around the World in Eight Hours" has just  1 . It sounds
interesting, doesn't it? This CD-ROM can help you learn English and  2  at the same time. It is designed  3  
Nancy Jackson.
     Yes, she is the  4  of children's favourite CD-ROM "Online Traveller"!
     The main character of this wonderful new game is Itchy Feet. He is a thirteen-year-old boy and  5  
travelling. One day, he was lying on the grass and  6  the beautiful blue sky when he  7  and had a very
strange dream.
     In his dream, he saw a golden cloud. These words  8   on it."Welcome, travellers! See those big  9  of
different colours with questions on them? You get a point every time you answer a question  10 . When you
have got enough points, a cloud will come down and carry you off to a place you have  11  visited before. Are
you ready? Let's go!"
     When you play this game, you will play the role of Itchy Feet. This game has eight levels, and each level
will  12  you about an hour to finish. If you are  13 , you can travel around the world in eight hours!
     This CD-ROM helps you learn English by testing your knowledge of English grammar and vocabulary.
Every time you reach a  14  place, you will see a lot of useful  15  about that place on your screen. For
example, when you reach London, you will learn  16  the Museum of London and many  17   interesting
places.
     Every time you pass a level, you will see a map of the  18 . The places you have visited are marked in
bright purple. What will you see   19  you pass all eight levels? Well, that is for you to find out!
     This game is one of  20  on the market. You will really enjoy it. You can get it in all computer shops
and bookshops. Get it now before it is sold out!
( )1. A. come over    
( )2. A. Math         
( )3. A. by           
( )4. A. dancer       
( )5. A. love         
( )6. A. watching     
( )7. A. fell sleep   
( )8. A. are written  
( )9. A. cloud        
( )10. A. excitedly   
( )11. A. never       
( )12. A. spend       
( )13. A. silly       
( )14. A. old         
( )15. A. information 
( )16. A. over        
( )17. A. others      
( )18. A. China       
( )19. A. before      
( )20. A. the best    
B. come in    
B. History    
B. on         
B. teacher    
B. loving     
B. looking at 
B. felt asleep
B. were written
B. cloudy     
B. incorrectly
B. ever       
B. take       
B. angry      
B. beautiful  
B. information
B. from       
B. another    
B. French     
B. after      
B. good       
C. come out      
C. Physics       
C. in            
C. nurse         
C. loves         
C. seeing        
C. fell asleep   
C. was written   
C. clouds        
C. slowly        
C. always        
C. cost          
C. smart         
C. quiet         
C. an information
C. about         
C. the other     
C. Japan         
C. and           
C. better        
D. come on       
D. Geography     
D. with          
D. designer      
D. to love       
D. finding       
D. fall asleep  
D. is written    
D. clouds'       
D. correctly     
D. sometimes     
D. pay for       
D. generous      
D. new           
D. a information 
D. to            
D. other         
D. world         
D. or                                     
D. worst         
单项选择题