问题 选择题

对下列概念、公式的理解,正确的是(  )

A.根据E=,电场中某点的电场强度和检验电荷的电荷量q成反比

B.根据C=,电容器极板上的电荷量每增加1 C,电压增加1 V,则该电容器的电容为1 F

C.根据W=qU,一个电子在电势差为1 V的两点间被电场加速,电场力做功为1 eV

D.根据Uab,若带电荷量为1×10-5 C的正电荷从a点移动到b点,克服电场力做功为1×10-5 J,则a、b两点的电势差为Uab=1 V,且a点电势比b点高

答案

BC

题目分析:每滴液滴在下落过程中A带电荷量不同,由电场自身决定,与检验电荷无关,所以A错误;根据C=,当电容器极板上的电荷量每增加1 C,电压增加1 V,则该电容器的电容为1 F,所以B正确;根据W=qU,一个电子在电势差为1 V的两点间被电场加速,由于电子的电荷量大小为e,故电场力做功为1 eV,所以C正确;克服电场力做功为1×10-5 J,则电场力做功Wab=-1×10-5 J,可得Uab=-1 V,a点电势比b点低,故D错误。

完形填空
完形填空。
     I’m Mike and I come from England. Now I’m    1   at Beijing International School. I’m good   2   all
my subjects and I enjoy    3   in China.
     In   4   , the Olympic Games will be held (举行) in London. It’s    5   news for English people. At that
time many foreigners are going to   6   London. My friends and    7   are going to    8    them around Big
Ben, Buckingham Palace and    9   because they are very famous in the world. I’m going to   10   with the Chinese   11   in Chinese. But now I don’t know    12 _ Chinese, so I must study it very   13   . From now on,   14    will take me two hours to learn Chinese every day. I’m looking forward   15    the Olympic
Games.
( )1. A. read          
( )2. A. at            
( )3. A. live          
( )4. A. 2007          
( )5. A. tiring        
( )6. A. visit          
( )7. A. me            
( )8. A. take          
( )9. A. the Great Wall
( )10. A. tell          
( )11. A. visiter      
( )12. A. many          
( )13. A. harder        
( )14. A. it            
( )15. A. watch        
B. reading        
B. in            
B. living        
B. 2008          
B. boring        
B. find          
B. I              
B. look          
B. the River Seine
B. say            
B. visiters      
B. much          
B. hard          
B. it’s          
B. to watch      
C. study        
C. for          
C. to live      
C. 2012        
C. bad          
C. sweep        
C. my          
C. put          
C. Tower Bridge
C. speak        
C. visitor      
C. few          
C. hardly      
C. that        
C. to watching  
D. studying    
D. with        
D. lives        
D. 2009        
D. exciting    
D. clean        
D. mine        
D. invite      
D. Victoria Peak
D. talk        
D. visitors    
D. a few        
D. careful      
D. this        
D. watching    
选择题