小李和小明同学做“研究导体对电流的阻碍作用与导体的长度和横截面积的关系”实验.他

题型:问答题

问题:

小李和小明同学做“研究导体对电流的阻碍作用与导体的长度和横截面积的关系”实验.他们分别选用材料相同,但长度、横截面积不同的若干导体进行实验.他们分别将导体接在同一电源的两端,用电流表测得通过导体的电流,并记录数据如表一、表二所示.

表一

实验

序号

长度

(米)

横截面积

(毫米2

电流

(安培)

10.1010.2
20.2020.2
30.3030.2
表二

实验

序号

长度

(米)

横截面积

(毫米2

电流

(安培)

40.1020.4
50.2040.4
60.3060.4
(1)在实验过程中,小李和小明同学是根据______来比较导体对电流阻碍作用大小的.

(2)分析比较实验序号1、4(或2、5,或3、6)中的数据及相关条件,可得出的初步结论是:______.

(3)分析比较实验序号______的数据及相关条件,可得出的初步结论是:同种材料、横截面积相同的导体,长度越短,导体对电流的阻碍作用越小.

(4)小李进一步分析了表一和表二的数据,可得出的结论是:同种材料制成的导体,当______相同时,导体对电流的阻碍作用相同.

考点:影响电阻大小的因素
题型:问答题

A few years ago, I went to China with my parents. The five-day trip left me with a deep impression.

As the capital of China, Beijing is a very beautiful city with fresh air and clean streets which make the travelers feel very pleased. To my surprise, many people there were learning English. Later I was told that they did so because Beijing would hold the 29th Olympic Games and they wanted most foreigners to understand them. They strictly kept the traffic rules. When there was a red light, no one was seen crossing the street.

Of all the places I visited, I liked the Summer Palace best. To our surprise, although it was winter when we were there, we still saw green trees and many fresh flowers. The whole park was very beautiful.

We visited a very modern football field. We were told the buildings where the Olympic Games would be held were even better than that. I also enjoyed skiing in Xiangshan. Skiing is an interesting and exciting sport liked by many people.

In my eyes, China is a nice place and Chinese people are very kind. In Beijing Station, there were so many people, and most of them were going home to spend the Spring Festival—the most important Chinese festival, with their families. Passengers helped each other carry luggage(行李), and they were very kind to foreigners. We were given a card by the hotel we stayed at, on which was the address of the hotel. With the card we never got lost in the city.

The five days passed quickly, but the trip left me a lot of sweet memories.

根据短文,从题中所给的A、B、C、D四个选项中,选择最佳答案。(10分)

小题1:From the passage, we know the Summer Palace ______ .

A.has flowers only in summer

B.is worth visiting all the year round

C.is a place where people visit only in summer

D.is a place where many people ski in winter小题2:The writer enjoyed ______ in Xiangshan.

A.skating

B.swimming

C.skiing

D.board-skating小题3:The five-day trip of Beijing was ______.

A.during New Year’s Day

B.after the Spring Festival

C.on the Mid-Autumn Day

D.before the Spring Festival小题4:The foreigners were given a card each by the hotel ______.

A.so that they could easily find their hotel

B.in order to go shopping

C.so they could get something freely from the hotel

D.as the New Year’s gift小题5:In the writer’s eyes, Chinese people ______.

A.are kind

B.are helpful

C.strictly kept the traffic rules

D.all of the above

题型:问答题

关于锅炉表面排污的下列说法中错误的是()。

A.一般应在投药前进行

B.最好定期定量进行

C.排污前将锅水加至最高水位

D.排污时无须停炉或减低负荷

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TPS系统中自定义键的目标文件后缀是()

A.SO

B.OS

C.KS

D.KO

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《工程岩体分级标准>GB50218-94中规定围岩强度比Rczmax值属于下列()范围为一般地应力。

A.大于7

B.4~7

C.小于4

D.小于2

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T型、III-1-TM型、SZ-1-TM型缓冲器检修后组装有何要求?

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