【題目】如圖所示，把一重力不計(jì)的通電直導(dǎo)線AB水平放在蹄形磁鐵磁極的正上方，導(dǎo)線可以在空間自由運(yùn)動(dòng)，當(dāng)導(dǎo)線通以圖示方向電流I時(shí)，導(dǎo)線的運(yùn)動(dòng)情況是（從上往下看）（ ）

A．順時(shí)針方向轉(zhuǎn)動(dòng)，同時(shí)下降

B．順時(shí)針方向轉(zhuǎn)動(dòng)，同時(shí)上升

C．逆時(shí)針方向轉(zhuǎn)動(dòng)，同時(shí)下降

D．逆時(shí)針方向轉(zhuǎn)動(dòng)，同時(shí)上升

【答案】C

【解析】如圖所示，將導(dǎo)線AB分成左、中、右三部分。中間一段開始時(shí)電流方向與磁場(chǎng)方向一致，不受力；左端一段所在處的磁場(chǎng)方向斜向上，根據(jù)左手定則其受力方向向外；右端一段所在處的磁場(chǎng)方向斜向下，受力方向向里。當(dāng)轉(zhuǎn)過一定角度時(shí)，中間一段電流不再與磁場(chǎng)方向平行，由左手定則可知其受力方向向下，所以從上往下看導(dǎo)線將一邊逆時(shí)針方向轉(zhuǎn)動(dòng)，一邊向下運(yùn)動(dòng)，C正確。

練習(xí)冊(cè)系列答案
相關(guān)習(xí)題

科目：高中地理 來源： 題型：

【題目】

Did you see American figure skater, Jeremy Abbott, crash to the ice during the short program at the Sochi Olympics, rolling into the wall, clutching his side in pain. Ten seconds later, he got up and continued his skate—despite the pain, embarrassment and fear. All I could think was: this kid’s got courage. In business we have a word for it—resilience, the ability to gain strengths and confidence from overcoming unpleasant events.

However, opposite examples appeared in Sochi Olympics as well. For them, failure is someone else’s fault, because they do not accept personal responsibility. Therefore, they have to pay a high price for this attitude. After years of studying failure, I have learned one thing: modesty and open-mindedness in the face of mistakes is the single best thing you can do to improve results. Everyone fails, but not everyone recovers from failure. The key is to learn from it rather than get beaten by it.

The good news is that each of us has the potential to live a resilient life on and off the job. It may be difficult, but that just makes it all the more powerful and important. If you believe the above paragraph to be true, then you’re probably more resilient than you think you are. It takes confidence to be resilient but that too much confidence is a killer is so true of leadership. For example, Ron Johnson, the ill-fated CEO of JC Penney, was so stubborn that he completely missed all sorts of signals from employees and customers and instead listened to all those who agreed with him, which failed his strategy. Bouncing back from failure requires that you recognize something has gone wrong, and you were the one who made it happen.

The challenge of resilience is not just about our work. When parents help their kids deal with every challenging situation, they are doing an unhelpful action to their children. Parents want to protect their kids from failure, but doing so takes away the opportunity from them to practice not

just a life skill but an essential work skill. When self-esteem becomes more important than results, we are accidentally training young people to become less adaptable, not more.

Resilience is not just about getting up off the floor, but also being ready for whatever comes next, even when you don’t know what it is. Failures and setbacks are no longer unusual events, but regular features of a dynamic, competitive and highly demanding work environment. Getting up to finish your skate is no longer optional.

【1】The example of Jeremy Abbott shows that one should ______.

A. recover from failure

B. stick to his own viewpoint

C. take others’ opinions to heart

D. challenge difficulties bravely

【2】According to the author, what can best build up resilience?

A. Being positive and powerful.

B. Being competitive and helpful.

C. Being modest and open-minded.

D. Being confident and responsible.

【3】 Which of the following examples shows us resilience?

A. A teacher offers students timely help and care.

B. A determined athlete practices skating hard every day.

C. A confident leader persuades his staff to follow his plan.

D. A student has got a low grade but continues to work hard.

【4】Which might be the best title for the passage?

A. An Example of Resilience: Ron Johnson

B. Resilience: A Lesson from Sochi

C. Optional Challenges of Resilience

D. Resilience in Family Education

查看答案和解析>>

科目：高中地理 來源： 題型：

【題目】2016年9月11日，山東青島市即墨于21時(shí)25分發(fā)布雷電黃色預(yù)警信號(hào)。當(dāng)晚受雷陣雨影響，空氣潮濕。距地面一定高度的空中有兩塊相距3 km的足夠大的云團(tuán)，兩塊云團(tuán)正在以5 m/s的相對(duì)速度靠近，不斷與空氣摩擦帶電。設(shè)兩云團(tuán)之間電勢(shì)差保持3×109 V不變，已知發(fā)生放電時(shí)的電場(chǎng)強(qiáng)度為3×106 V/m，云團(tuán)間的電場(chǎng)可視為勻強(qiáng)電場(chǎng)，則大約經(jīng)過________秒，將會(huì)發(fā)生放電現(xiàn)象；在這次放電中，若從一塊云團(tuán)移到另一塊云團(tuán)的電荷量為500 C，閃電歷時(shí)0.01 s，則此過程中的平均電流為________安培。

查看答案和解析>>

科目：高中地理 來源： 題型：

【題目】A

In 1995, Oseola McCarty gave a present of $ 150,000 to the University of Southern Mississippi. She wanted to help poor students. It was a very generous thing to do. But her friends and neighbors were surprised. McCarty was a good woman. She went to church. She was always friendly and helpful. But everyone in her town knew that McCarty was not rich. In fact, she was poor.

How did a poor 86-year-old woman have so much money? Oseola McCarty was born in 1908 in Hattiesburg, Mississippi. She had to leave school when she was eight years old to help her family. She took a job washing clothes. She earned only a few dollars a day. Oseola washed the clothes by hand. Then she hung the clothes to dry. She did this for nearly 80 years. In the 1960s’ she bought an automatic washer and dryer. But she gave them away. She did not think they got the clothes clean enough! At that time, many people started to buy their own washers and dryers. McCarty did not have much work, so she started to iron clothes instead.

McCarty never married or had children. Her life was very simple. She went to work and to church. She read her Bible. She had a black-and-white television. But she did not watch it very much. It had only one channel.

McCarty saved money all her life and eventually had about $250,000.When she was 86, a lawyer helped her make a will. She left money to the church, her relatives, and the university. McCarty just wanted to help others. She did not think she was a special person. But then people found out about her present to the university. She received many honors(榮譽(yù)). She even flew in an airplane for the first time! Oseola McCarty died in 1999.She was a shy and ordinary woman who became famous.

【1】Oseola McCarty gave $150,000 to the University of Southern Mississippi __________.

A. to help the poor students

B. to surprise her friends and neighbors

C. to show her generosity

D. to be a good and rich woman

【2】From the story we know ___________.

A. McCarty was born in a poor family near the University of Southern Mississippi

B. everyone was surprised because they thought McCarty had no education

C. washers and dryers brought a change in McCarty’s life

D. McCarty gave half of her money to the church and her relatives.

【3】 Which of the following is true?

A. McCarty had to work to help her family after school every day.

B. McCarty learned to read the Bible by herself in the school.

C. McCarty made one third of her money by washing and ironing clothes.

D. McCarty did not have her own family because she had no husband or children.

【4】 From which of the following can we tell McCarty lived a simple life?

A. She worked hard all her life.

B. She didn’t think she was special.

C. She didn’t have many interests.

D. She had a TV set with many channels.

查看答案和解析>>

科目：高中地理 來源： 題型：

【題目】B

Katharine Graham, once described as ＂the most powerful woman in America＂, was the owner and publisher of The Washington Post newspaper. Under her leadership, it became one of the most important newspapers in the country.

Katharine Graham was born in New York in 1917. Graduating from the University of Chicago in 1938, Katherine got a job as a reporter for a newspaper in San Francisco, California. In 1933, Katharine’s father bought a failing newspaper, The Washington Post. It was the least successful of five newspapers in Washington.

Soon Katharine returned to Washington and got a job editing letters to the editor of her father’s newspaper. In 1946, her husband Philip Graham became publisher of The Washington Post. When she was 46, her husband died, leaving Katharine Graham four children to raise and a newspaper to operate.

At first, she was concerned only with finding a way to keep control of The Washington Post until her sons were old enough to lead it. She had no training in business or experience in operating a large company and decided to learn. She hired excellent reporters and editors. In 1969, Missus Graham became publisher as well as president of The Washington Post company. In the 1970s, The Washington Post became famous around the world. Katharine Graham also played an important role in supporting women by employing more of them. When she was eighty years old, Katharine Graham wrote a very popular book called Personal History about her life, which won a Pulitzer prize for biography in 1998. Friends of Katharine Graham said she used her intelligence and bravery to improve the American media.

【1】 Katharine Graham first worked as ___________.

A. a reporter B. an editor

C. a publisher D. a manager

【2】 When Katharine’s father bought The Washington Post, __________.

A. it had been in business for a short time

B. it was one of the largest newspapers in the US

C. it was in a difficult situation

D. it had enjoyed great success and fame

【3】The most difficult time for Katharine came when __________.

A. her father died

B. her husband died

C. she took control of The Washington Post

D. she returned home to raise her four kids

【4】What can we infer from the passage?

A. The newspaper was failing under Katharine’s control.

B. There were more women editors than men editors in The Washington Post.

C. Katharine probably had a difficult time operating the newspaper at first.

D. Katharine was best known for her book Personal History.

查看答案和解析>>

科目：高中地理 來源： 題型：

【題目】短文改錯(cuò)

假定英語課上老師要求同桌之間交換修改作文，請(qǐng)你修改你同桌寫的以下作文。文中共有10處語言錯(cuò)誤，每句中最多有兩處。錯(cuò)誤涉及一個(gè)單詞的增加、刪除或修改。

增加：在缺詞處加一個(gè)漏詞符號(hào)（∧），并在其下面寫出該加的詞。

刪除：把多余的詞用斜線（\）劃掉。

修改：在錯(cuò)的詞下劃一橫線，并在該詞下面寫出修改后的詞。

注意：

1. 每處錯(cuò)誤及其修改均僅限一詞；

2. 只允許修改10處，多者（從第11處起）不計(jì)分。

It was the International Women’s Day. Li Hua had a good idea and tells his father that he was going to do everything to celebrate it. He asked his father to help him. First they decided to do some housework, that was always done by his mother. Li Hua cleaned the house completely while his father did some shop. Then they made a good meal, cooking fish, pork, chicken, soup but some other delicious dishes. Li Hua laid the table and set a vase full with flowers in the middle of the table. After that they hid them behind the door and waited the mother in order to give her a surprise. When his mother came back and saw the delicious food, she felt happily.

查看答案和解析>>

科目：高中地理 來源： 題型：

【題目】聽下面一段對(duì)話，完成五道小題，每小題僅填寫一個(gè)詞。這段對(duì)話你將聽兩遍。

查看答案和解析>>

科目：高中地理 來源： 題型：

【題目】目前有些居民區(qū)內(nèi)樓道燈的控制，使用的是一種延時(shí)開關(guān)。該延時(shí)開關(guān)的簡化原理如圖所示。圖中D是紅色發(fā)光二極管（只要有很小的電流通過就能使其發(fā)出紅色亮光），R為限流電阻，K為按鈕式開關(guān)，虛線框內(nèi)S表示延時(shí)開關(guān)電路，當(dāng)按下K接通電路瞬間，延時(shí)開關(guān)觸發(fā)，相當(dāng)于S閉合，這時(shí)釋放K后，延時(shí)開關(guān)S約在1 min后斷開，電燈熄滅。根據(jù)上述信息和原理圖，我們可推斷：

按鈕開關(guān)K按下前，發(fā)光二極管是________（填“發(fā)光的”或“熄滅的”），按鈕開關(guān)K按下再釋放后，電燈L發(fā)光持續(xù)時(shí)間約________min。這一過程中發(fā)光二極管是________。限流電阻R的阻值和燈絲電阻RL相比，應(yīng)滿足R________RL的條件。

查看答案和解析>>

科目：高中地理 來源： 題型：

【題目】如圖所示是一種延時(shí)開關(guān)，當(dāng)S1閉合時(shí)，電磁鐵F將銜鐵D吸下，將C線路接通。當(dāng)S1斷開時(shí)，由于電磁感應(yīng)作用，D將延遲一段時(shí)間才被釋放。則下列說法中正確的是（ ）

A．由于A線圈的電磁感應(yīng)作用，才產(chǎn)生延時(shí)釋放D的作用

B．由于B線圈的電磁感應(yīng)作用，才產(chǎn)生延時(shí)釋放D的作用

C．如果斷開B線圈的開關(guān)S2，無延時(shí)作用

D．如果斷開B線圈的開關(guān)S2，延時(shí)將變長

查看答案和解析>>

同步練習(xí)冊(cè)答案