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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。
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( )1. A. come over    
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( )18. A. China       
( )19. A. before      
( )20. A. the best     		B. come in    
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B. looking at 
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B. cloudy     
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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   
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C. always        
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C. smart         
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单项选择题

下列行为中，应征增值税的是( )。

A．银行销售金银的业务

B．银行开办的融资租赁业务

C．集邮公司销售护邮袋

D．发行 * * 票业务
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