问题 问答题

(选修模块3-4)

(1)下列说法中正确的是______

A.照相机、摄影机镜头表面涂有增透膜,利用了光的干涉原理

B.光照射遮挡物形成的影轮廓模糊,是光的衍射现象

C.太阳光是偏振光

D.为了有效地发射电磁波,应该采用长波发射

(2)甲、乙两人站在地面上时身高都是L0,甲、乙分别乘坐速度为0.6c和0.8c(c为光速)的飞船同向运动,如图1所示.此时乙观察到甲的身高L______L0;若甲向乙挥手,动作时间为t0,乙观察到甲动作时间为t1,则t1______t0(均选填“>”、“=”或“<”).

(3)x=0的质点在t=0时刻开始振动,产生的波沿x轴正方向传播,t1=0.14s时刻波的图象如图2所示,质点A刚好开始振动.

①求波在介质中的传播速度;

②求x=4m的质点在0.14s内运动的路程.

答案

(1)A、在选择增透膜时,一般是使对人眼灵敏的绿色光在垂直入射时相互抵消,这时光谱中其它频率的光将大部分抵消,因此,进入镜头的光有很多,但以阻挡绿光为主,这样照相的效果更好.对于增透膜,有约1.3%的光能量会被反射,再加之对于其它波长的光,给定膜层的厚度是这些光在薄膜中的波长的

1
4
倍,从薄膜前后表面的反射绿光相互抵消.这是利用了光的干涉原理.故A正确.

B、光照射遮挡物形成的影轮廓模糊,是由于光的衍射造成的.故B正确.

C、太阳光是自然光,各个方向振动的光都有.故C错误.

D、频率越高,波长越短,电磁波发射效率越高,故为了有效地发射电磁波,应该采用微波发射.故D错误.

故选AB

(2)身高L=L0,因为人是垂直于物体速度方向的,没有尺缩效应,故乙观察到甲的身高L=L0;根据相对论的钟慢效应,可以推测两人在接近光速运动时,相对地球来说时间都变慢了,但乙相对于甲的速度更大,因此可以推测,乙的钟要更慢一点(相对于甲),故乙观察到甲动作时间为t1>t0

(3)①由题知,振动在△t=0.14s时间内传播的距离为△x=7m,则该波的传播速度为 v=

△x
△t

代入数据得 v=50m/s

②在0.14s内,x=4m的质点只振动了

3
4
个周期,所以该质点运动的路程:s=3A=15cm

故答案为:(1)AB,(2)=,>

(3)①波在介质中的传播速度为50m/s;②x=4m的质点在0.14s内运动的路程为15cm.

阅读理解

It was a lovely day at the park and Stella Bianchi was enjoying the sunshine with her two children when a young boy, aged about four, approached her two-year-old son and pushed him to the ground.

“I’d watched him for a little while and my son was the fourth or fifth child he’d pushed,” she says. “I went over to them, picked up my son, turned to the boy and said, firmly, ‘No, we don’t push.’” What happened next was unexpected.

“The boy’s mother ran toward me from across the park,” Stella says, “I thought she was coming over to apologize, but instead she started shouting at me for blaming her child. All I did was let him know his behavior was unacceptable. Was I supposed to sit back while her kid did whatever he wanted and hurt other children?”

Getting your own children to play nice is difficult enough. Dealing with other people’s children has become a hidden danger.

In my house, jumping on the sofa is not allowed. In my sister’s house it’s encouraged. I find myself saying “no” a lot when her kids are over at mine. That’s OK between sisters but becomes dangerous when you’re talking to the children of friends or acquaintances.

“Kids aren’t all raised the same,” agrees Professor Naomi White of Monash University.” But there is still an idea that they’re the property of the parent. We see our children as a mirror of ourselves, so if you’re saying that my child is behaving improperly, then that’s somehow a criticism(批评) of me.”

In those situations, it’s difficult to know whether to approach the child directly or the parent first. There are two opinions.

“I’d go to the child first,” says Andrew Fuller, author of Tricky Kids. “Usually a quiet reminder that ‘we don’t do that here’ is enough. Kids have antennae (直觉) for how to behave in different settings.”

He points out bringing it up with the parent first may make them feel careless, which could cause problems. Of course, approaching the child first can bring its own headaches, too.

This is why White recommends that you approach the parents first. Raise your concerns with the parents and ask them to deal with it,” she says.   

Asked how to approach a parent in this situation, psychologist Meredith Fuller answers: “Explain your needs as well as stressing the importance of the friendship. Start with something like: ‘I know you’ll think I’m silly but in my house I don’t want…’” 

小题1:What did Stella Bianchi expect the young boy’s mother to do when she talked to him?

A.Make an apology

B.Come over to stop her

C.Blame her own boy

D.Take her own boy away小题2:What does the author say about dealing with other people’s children?

A.It’s important not to hurt them in any way

B.It’s no use trying to stop their wrongdoing

C.It’s advisable to treat them as one’s own kids

D.It’s possible for one to get into lots of trouble小题3:According to professor Naomi White, when one’s kids are criticized, their parents will probably feel ______.

A.discouraged

B.hurt

C.puzzled

D.affected小题4: What should one do when seeing other people’s kids misbehave according to Andrew Fuller?

A.Talk to them directly in a mild way

B.Complain to their parents politely

C.Simply leave them alone

D.Punish them lightly

问答题 简答题