问题 计算题

(1)下列过程中,没有利用电磁波的是_______________。

A.电视机接收卫星电视信号       B.移动电话通话

C.电风扇通电后正常运转         D.雷达发现飞机

(2)[3分]物理学中描述电场强弱的物理量是_________。

A.电流      B.电荷量        C.电场强度       D.磁感应强度

(3)[3分]在国际单位制中,电容的单位是____________

A.法拉     B.伏特      C.安培       D.欧姆

(4)[3分]下列说法正确的是__________

A.电磁感应现象是牛顿发现的

B.交流发电机发出的电流方向不变

C.升压变压器的原、副线圈匝数相同

D.远距离输电要用高电压,是为了减少输电线上的电能损失

(5)[4分]当螺线管中通入如图所示的电流时,位于它B端附近的小磁针____________(填“会”或“不会”)发生偏转,螺线管A端的磁极是____________(填“N极”或“S极”)

(6)[6分] 一根长L=0.2m的直导线,通有I=2A的电流,放入磁感应强度B=1T的匀强磁场中。问:

①当导线方向与磁场方向平行时,导线会不会受到安培力?

②当导线方向与磁场方向垂直时,导线受到的安培力是多大?

答案

(1) C (2) C (3)A(4)D(5)会N极(6)①不会     ②0.4N

题目分析:(1)电风扇通电后正常运转是将电能转化为机械能,没有用到电磁波,故选C

(2)物理学中描述电场强弱的物理量是电场强度,

(3)电容的单位是法拉,伏特是电压的单位,安培是电流的单位,欧姆是电阻的单位,故选A

(4)法拉第发现电磁感应,A错误,交流电的方向每个周期变化一次,B错误,升压变压器原线圈中的匝数大于副线圈中的匝数,C错误,输电过程中输送功率一定,所以根据公式可得输送电压越高,输送电流就越小,即输电线上损耗的电能就越小,D正确,故选D

(5)根据电流的磁效应可得当螺线管中通入如图所示的电流时,螺线管中产生磁场,所以B端附近的小磁针发生偏转,,根据安培定则可得A端的磁极为N极,

(6)①当通电导线和磁场方向平行时,没有磁场力的作用,

②根据公式可得F=0.4N

点评:对这些基础知识,要求比较高,所以在平时的学习中需要注意

阅读理解

Once upon a time, there lived a rich man. He had a servant (仆人). He and the servant loved wine (酒)and good food very much. Each time the rich man left his home, the servant would drink the wine and eat up all the nice food in the house. The rich man knew what his servant did, but he had never caught his servant doing that.

  One morning, when he left home, he said to the servant, “Here are two bottles of poison (毒药) and some nice food in the house. You must take of them.” With these words, he went out.

  But the servant knew that the rich man had said was untrue. After the rich man was away from his home, he enjoyed a nice meal. Because he drank too much, he was drunk(醉了) and fell to the ground. When the rich man came back, he couldn’t find his food and his wine. He became very angry. He woke the servant up. But the servant told his story very well. He said a cat had eaten up everything. He was afraid to be punished(惩罚), so he drank the poison to kill himself.

小题1:In the story, _______ liked wine and good food very much.

A.the rich man

B.the servant

C.both A and B

D.neither A and B小题2:The rich man knew that it was _____ that drank the wine and ate up all the nice food.

A.the cat

B.himself    

C.nobody

D.the servant小题3:The rich told the servant that there was poison(毒药) in the two bottles, because ________.

A.there was in fact poison in the bottles

B.did not want the servant to drink his wine

C.he wanted to kill the cat

D.he wanted to kill the servant小题4:In fact, _______ ate all the nice food and drank the wine.

A.the servant   

B.cat   

C.the rich man  

D.nobody小题5:From the story, we know that the servant is very _______.

A.lazy   

B.bad   

C.clever   

D.kind

单项选择题 A1/A2型题