试题与答案

如图所示,处在磁感应强度为B的匀强磁场中的单匝矩线圈abcd,以恒定的角速度ω绕

题型:选择题

题目:

如图所示,处在磁感应强度为B的匀强磁场中的单匝矩线圈abcd,以恒定的角速度ω绕ab边转动,磁场方向垂直于纸面向里,线圈所围面积为S,线圈导线的总电阻为R.t=0时刻线圈平面与纸面重合,且cd边正在离开纸面向外运动.则正确的是(  )

A.时刻t线圈中电流的瞬时值icosωt

B.线圈中电流的有效值I

C.线圈中电流的有效值I=

D.线圈消耗的电功率P

答案:

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D题目分析:根据教材知识,在学习中感受到压力是正常的。适度的焦虑体现了我们对考试积极认真的态度,但过度的考试焦虑,则会干扰我们的学习,对身心健康造成不利影响。我们要克服过度的焦虑,从容对面对考试。...

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题型:阅读理解

Quit while you're ahead

I am one of those people who are terrible at saying no.I take on too many projects at once, and spend too much of my time doing things I'd rather not be doing.I get work done, but it's not always the best I can do, or the best way I could spend my time.

That's why my newest goal, both as a professional and a person, is to be a quitter.

Being a quitter isn't being someone who gives up, who doesn't see important things through to the end.I aspire (渴望) to be the opposite of that.The quitter I want to be is someone who gets out when there's no value in what he's doing, or when that value comes at the expense of something more important.

A friend of mine once told me, "I knew I was an adult when I could stop reading a book, even after getting 500 pages into it." Strange though it sounds, we all tend to do this.We get involved in something, realize we don't want to be a part of it, but keep on going.We say "Well, I've already invested so much time in this, I might as well stick it out."

I propose the opposite: quit as often as possible, regardless of project status or time invested.If you're reading a book, and don't like it, stop reading.Cut your losses, realize that the smartest thing to do is to stop before your losses grow even more, and quit.Instead of reading an entire book you hate, read half of a bad one and half of a good one.Isn't that a better use of your time?

Step back for a second.Let's learn how to say "no" at the beginning, or in the middle, and free up more of our time to do the things we'd like to be doing, and the things actually worth doing. Saying no is hard, and admitting a mistaken yes is even harder.If we do both, we'll start to make sure that we're spending our time creating value, rather than increasing our losses.Let's be quitters together.

小题1:The author wants to be a quitter, because he _____.

A.hopes to improve his personality

B.wishes to have more time for relaxation

C.expects to make more efficient use of his time

D.has found it hard to do several things at one time小题2:In what circumstances does the author suggest quitting is a good idea?

A.When you feel tired and need a rest.

B.When you know a task cannot be finished.

C.When you meet with difficulties along the way in your life.

D.When you realize what you are doing is not worth the time.小题3:If you stop reading a book you hate, the author might think that ______.

A.you are wise to cut your losses

B.it's a pity that you have wasted so much time

C.you should finish a book that you have started

D.you should regret choosing the wrong book小题4:The message the author tries to convey is to ______.

A.learn to say no

B.live your life to the fullest

C.create more value

D.stop doing many things at once

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