搜题请搜索小程序“爱下问搜题”
问题 填空题

如图所示，在平行金属带电极板MN的电场中将电荷量为-4×10-6C的点电荷从A点移到M板，静电力做负功8×10-4 J，把该点电荷从点移到N板，静电力做正功为4×10-4J，N板接地．则：

（1）A点的电势φA是______V，

（2）UMN等于______V

（3）M板的电势ϕM是______V．

答案

（1）A、N间的电势差：UAN=

WAN
q
=
4×10-4
-4×10-6
V=-100V，又：UAN=φA-φN，φN=0，则A点的电势：φA=-100V．

（2）UMN=

WMN
q
=
WMA+WAN
q
=
8×10-4+4×10-4
-4×10-6
V=-300V．

（3）UMN=φM-φN，φN=0，则M板的电势：φM=-300V．

故答案为：（1）-100；（2）-300；（3）-300

改错题

改错题。

     For different reasons，people are pouring into big cities，which cause much more trouble

than expected.As the growth of the population，city problems are grown day by day.To begin

with，big cities are becoming so crowded that it makes find jobs very difficult.As a result，

people without jobs are likely to become danger to our society.In additional，the environment

is getting worse and worse，but there is pollution and traffic problems as well as.We can’t

choose but face with them.In my opinion，big cities need to control the population to help

develop itself for the future.In terms of improving the environment, every citizen should be

called on to contribute to protect the environment.
查看答案
单项选择题

（）是指经中国人民银行批准的直接参与者和特许参与者开设的用于资金清算的存款账户。

A.准备金账户

B.备付金账户

C.内部账户

D.清算账户
查看答案