问题 填空题

某导体的电阻为10欧。10秒内通过导体横截面的电量为3库,则通过导体的电流为       安,电流通过导体做功       焦,若通过导体的电流为0.6安,则该导体的电阻为       欧。

答案

0.3;9;10;

题目分析:由电流公式可得:通过导体的电流

10s内电流通过导体所做的功;W=I2Rt=(0.3A)2×10Ω×10s=9J;

因导体电阻与流过导体的电流及导体两端的电压无关,故电流变为0.6A时,导体的电阻仍为10Ω;

所以答案为:0.3;9;10.

点评:由电流的定义可求得电流的大小;由电功公式可求得10s内电流所做的功;由电阻的性质可知电流变化后的电阻的阻值.

单项选择题 A1型题
完形填空
完形填空。
     Every country has its own dining customs. Americans feel that the first rule of being a   1    guest is to
be on time. If a person is invited to dinner at six thirty, the hostess   2   him to be there at six thirty or
    3      a few minutes after. Because she usually does the cooking, she has to time the meal   4    the hot
rolls and the coffee and the meat can be at their best when the guests come. If they are late, the food will
not be so   5 , and the hostess will be   6  .  7   the guest cannot come on time, he should call his host or
hostess on the phone, give the reason, and tell    8   what time he can come.   9   the situations, guests
sometimes bring a box of candy, a bottle of wine or a bunch of flowers to give to the hostess as a    10    
of appreciation.
     As guests continue to arrive, it is usually considered polite for the   11   in the group to   12   when a
woman enters the room and continue to stand until she is seated.    13  , most young people and some
groups of elder people   14    stress equality of the sexes no longer observe the custom. A visitor should
be   15   to each situation and follow the lead of the Americans present.
     When the guests sit down at a dinner table, it is a    16     for the men to help the ladies by pushing
their chairs under them. However, some Americans    17   do this, so the visitors must notice what others
do and do the   18  .  19   the meal is under way and if the dinner is in a private home, a guest    20 
 avoid embarrassment by leaving talk to someone else.
( )1. A. polite      
( )2. A. tells       
( )3. A. at most     
( )4. A. in case    
( )5. A. tender     
( )6. A. angry      
( )7. A. If          
( )8. A. at         
( )9. A. Looking at  
( )10. A. matter    
( )11. A. host       
( )12. A. smile     
( )13. A. As a result
( )14. A. whose     
( )15. A. aware      
( )16. A. custom    
( )17. A. even      
( )18. A. following  
( )19. A. Unless    
( )20. A. shouldn't  
B. elegant      
B. expects      
B. less than    
B. as long as  
B. nutritious  
B. nervous      
B. Unless      
B. in          
B. Combined with
B. heart        
B. men          
B. stand        
B. Moreover    
B. what        
B. similar      
B. regulation  
B. no longer    
B. same        
B. Until        
B. must        
C. honored    
C. asks        
C. at least    
C. so that    
C. good        
C. shameful    
C. Whether    
C. on         
C. Depending on
C. sense      
C. hostess    
C. applaud    
C. In addition  
C. who        
C. active      
C. habit      
C. still      
C. deed       
C. While      
C. needn't    
D. serious          
D. hopes            
D. more than        
D. on condition that
D. enough            
D. disappointed      
D. Although          
D. about            
D. Related to        
D. sign              
D. women            
D. nod              
D. However          
D. which            
D. sensitive        
D. principle        
D. no more          
D. example          
D. After            
D. may