在赤道附近有一根导线沿东西方向水平放置，当导线竖直向下运动时_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题填空题

在赤道附近有一根导线沿东西方向水平放置，当导线竖直向下运动时，会产生感应电动势，那么，这根导线的____________端电势较高（选填“东”或“西”）。

答案

东

分析：在赤道的上方磁场的方向从南向北，根据右手定则，判断电势高低．

在电源内部电流从负极流向正极．

解答：解：伸开右手，使拇指与其余四指垂直，并且与手掌在同一个平面内；

在赤道的上方磁场的方向从南向北，让磁感线从掌心进入，

拇指所指的方向指向导体棒运动方向，也就是竖直向下，

这时四指由西指向东，也就是感应电流的方向．

导线作为电源，在电源内部电流从负极流向正极，所以东端电势高．

故答案为：东．

点评：解决本题的关键掌握用右手定则判断感应电流的方向，伸开右手，使拇指与其余四指垂直，并且与手掌在同一个平面内；让磁感线从掌心进入，拇指所指的方向指向导体棒运动方向，这时四指指向就是感应电流的方向．

写句子

补充句子。

1．这件衣服 _______________________________

2．我国的国旗是________________________________

3．闪闪的星星像________________________________

4．菜园里有__________________________________

5．小松鼠_______________________________________

完形填空

In a land far away, once upon a time there was great poverty （贫困）,and only the rich could manage without great _36. Three of those rich men and their servants were_37_together on a road when they came to a very_38_village.
The first could not stand seeing the poverty, _39 he took all the gold and jewels from his wagons (四轮载重马车) and shared 40 out among the villagers. He wished them all the best of luck, and he left.
The second rich man ,seeing the _41 situation, stopped for a short time and gave _42 all his food and drink, since he _43 see that money would be of little _44 to them. He made sure that they each 45their fair share and would have enough food to _46 for some time . Then, he left.
The third rich man, on seeing such poverty, _47 and went straight through the _48 without stopping. The two other rich men saw this from a distance and commented with each other 49 the third rich man lacked sympathy. It was _50 that they themselves had been there to offer help.
However, three days later, they 51the third rich man ,who was coming in the opposite direction . He was 52 travelling quickly, but his wagons, 53 the gold and valuables they had been 54 ,were now full of farming tools and bags of 55 .He was rushing back to help them out of poverty.

B．expectations

A．the villagers

B．his servants

A．turned back