问题 选择题

如图所示,平行直线表示电场线,但未标方向,带电为+10-2C的微粒在电场中只受电场力作用,由A点移到B点,动能损失0.1J,若A点的电势为-10V,则:①B点的电势为10V  ②电场线方向从右向左③微粒的运动轨迹可能是轨迹1   ④微粒的运动轨迹可能是轨迹2

以上正确的是(  )

A.①③

B.②④

C.②③

D.①④

答案

由动能定理可知WE=△EK=-0.1J;

可知粒子受到的电场力做负功,故粒子电势能增加,B点的电势高于A点电势;而电场线由高电势指向低电势,故电场线向左,故②正确;

AB两点的电势差UAB=

WE
q
=-10V,则UA-UB=10V

解得UB=0V;故①错误

若粒子沿轨迹1运动,A点速度沿切线方向向右,受力向左,故粒子将向上偏转,故③正确;

若粒子沿轨迹2运动,A点速度沿切线方向向右上,而受力向左,故粒子将向左上偏转,故④错误;

故选C.

阅读理解

Honestly, since my son was born, I have thought a lot about how to raise a child. I once heard a story that told about when a baby was born. The story said that when a baby was born, a new master was born. The parents of that baby would become the servants. The question is: Why? Based on my observation, this phenomenon is true. Most parents who don't pay much attention to their kids have difficulties with their kids' attitude.

I'll make a comparison of how two families raise their children. The first one is a family with three children. Both mother and father never say "No" to their children's demands. As a result, all of their children became stubborn and won't listen to their parents’ words, "We can't."

The second family educated their children strictly from one year old to high school. The parents never approved or agreed directly to give their children what they wanted. They always postponed one or two days, even if they could afford it. Due to the way their parents educated them, these children understood that if they wanted something, they had to wait or they had to make an effort first. As a result, all the kids from the second family successfully graduated from university on time.

In my opinion, if we want to be successful parents and raise our children well, we have to start disciplining them when they are toddlers but not wait until they become teenagers.

小题1:Why did the writer give two different stories in this passage?

A.To help prove his opinion about raising a child.

B.To list different ways that parents may take.

C.To criticize some parents’ foolish action.

D.To prove that his way of education is right.小题2:What does the underlined word “postponed” in the third paragraph mean?

A.Carried out at once.

B.Gave up.

C.Put off.

D.Made a decision.小题3: In the writer’s opinion, which of the following about raising a child is TRUE?

A.Children should be respected once they were born.

B.Parents should educate their children as early as possible.

C.It is right time to educate their children when they are teenagers.

D.Children should be helped whenever they make mistakes.小题4: What do you think is the best title of this passage?

A.Make a comparison of how two families raise their children

B.To be successful parents

C.How to raise children well

D.Educate children strictly from one year old to high school

判断题