问题 实验题

小明在探究“导体的电阻跟哪些因素有关”的实验中,猜想:

①电阻可能跟导体的材料有关

②电阻可能跟导体的温度有关

③电阻可能跟导体的长度有关

④电阻可能跟导体的横截面积有关

右面表中是他在实验中所用的导体的相关记录:

(1)要探究猜想①,应该选用导体A和       (填导体编号)进行对比试验。

(2)要探究猜想③,应该选用导体C和       (填导体编号)进行对比试验。

(3)要探究猜想④,应该选用导体A和      (填导体编号)进行对比试验。

(4)以上实验用到了               的实验方法。

(5)小明发现实验器材中金属丝只有一根,其他器材足够,下面实验探究活动中他不可能完成的是:         

A.探究导体电阻与长度的关系

B.探究导体电阻与横截面积的关系

C.探究导体电阻与材料的关系

D.探究导体电阻与温度的关系

答案

(1)D(2)A(3)B(4)控制变量法(5)C

题目分析:电阻的大小决定于导体的材料、长度、横截面积以及温度;根据其探究的因素利用控制变量法来分析,要探究电阻与其中一个量是否有关,应控制其它因素都相同,据此来选择导体。

(1)要探究猜想①,根据控制变量法的思路,应该控制导体的长度、横截面积、温度都不变,因此应该选择导线A和D;(2)要探究猜想③,根据控制变量法的思路,应该控制导体的材料、横截面积、温度都不变,因此应该选择导线A和C;(3)要探究猜想④,根据控制变量法的思路,应该控制导体的长度、材料、温度都不变,因此应该选择导线B和A;(4)实验中用到了控制变量法;(5)探究导体电阻与材料的关系时,需要两根不同材料的电阻丝,所以不能探究导体电阻与材料的关系。

阅读理解

Edward Sims was born in 1892. He was the fifth child and only son of Herbert and Dora Sims. Herbert was a blacksmith(铁匠), and had a thriving trade making horseshoes. He was determined that his first-born son would follow him into the blacksmith. For this reason, Edward had to leave school at the age of 12,and worked with his father.

However, Edward was not cut out to be a blacksmith. Although he has an athletic body, he didn't have strong arms like his father, and he felt dizzy in the heat of the smithy.  When he tried to find alternative employment, he found it difficult because he had never learnt to read or write.

One day, he went for an interview at a solictior’s office. The job was a runner, taking documents from the office to other offices in the city. The solicitor was pleased to see that Edward was physically fit, but when he discovered that the young man couldn't read or write, he decided against employing him. "How can you deliver documents to other offices," he asked, "if you can't read the addresses on them?"

Bitterly disappointed, Edward left the building and went to wait for a tram to take him back to the suburb where his father’s smithy was. Next to the bus stop, a man was selling newspapers from a stand .

"Excuse me, son?" he said. "Would you look after my stand for a moment?"

For the next 20 minutes, Edward sold newspapers, lots of them. When the man came back, he was so delighted with his new assistant's honesty, that he offered him a job. Edward took it immediately.

In the next few months, the two men progressed from working on newspaper stands to selling newspapers, tobacco,confectionery(糖果点心)and other goods in a shop. Then they opened a second shop, and a third. Eventually, they had a chain of 25 shops in three cities.

Edward became very rich, so he employed a tutor to teach him to read and write. The tutor  was amazed at what Edward had achieved. "Imagine what you could do if you’d been able to read and write when you were younger!" he said.

“Yes!” said Edward. “I could have run myself to exhaustion delivering documents for a solicitor!”

小题1:What would be the best title for the text?

A.Success of illiterate newsboy

B.Local blacksmith becomes famous

C.The thriving trade of the blacksmith

D.Reading and writing-the road to success小题2:What can you infer from the underlined expression “not cut out to be” in the second paragraph?

A.Edward Sims did not like being a blacksmith.

B.Edward Sims did not like working with his father.

C.Edward Sims was not strong enough and it made him feel ill.

D.Edward Sims was good at it but wanted to do another job.小题3:When Edward applied for the job as a runner for a solicitor,        .

A.the solicitor turned him down because he wasn’t intelligent enough

B.the solicitor offered him the job because he was so fit

C.the solicitor gave him the job but told him he had to learn to read

D.the solicitor didn’t offer him the job because he couldn’t read小题4:Which of the following is NOT ture about Edward Sims?

A.He was such a good salesman that he went on to own 25 newsagent shops with another man.

B.The newspaperman liked him so much he gave him a job.

C.He ran himself into exhaustion delivering papers.

D.He learnt to read and write.

单项选择题