问题 问答题

下表是做探究“电阻大小与哪些因素有关”实验所用到的导线情况及测出通过导体的电流.(温度一定)

导体代号ABCD
长度1m1.01.00.51.0
横截面积/mm21.20.61.20.6
材料镍铬镍铬镍铬
电流/A1.40.72.84.2
电压/V3333
(1)选择A、B导体进行实验,得出的结论:______.

(2)为了探究导体电阻与材料的关系应选择______导体(填导体代号)进行实验.

(3)本实验采用的探究方法是:______.

答案

(1)分析A、B导体可知,长度、材料都相同,只有横截面积不同,因此选择A、B导体进行实验,得出的结论是:导体的电阻与导体的横截面积有关;

(2)为了研究导线电阻与材料是否有关,就要使导线的长度、横截面积相同,材料不同,根据表格中的数据,只有B、D两根导线符合条件.

(3)在物理学中,当探究一个物理量与多个物理量之间的关系时,就要利用控制变量法,因此该实验的探究方法为控制变量法.

故答案为:(1)导体的电阻与导体的横截面积有关;(2)B、D;(3)控制变量法.

阅读理解

阅读理解。

     I hated dinner parties. But I decided to give them another shot because I'm in London. And my friend

Mallery invited me. And because dinner parties in London are very different from those back in New York.

There, 'I’m having a dinner party' means: "I'm booking a table for 12 at a restaurant you can't afford and

we'll be sharing the checque evenly, no matter what you eat. " Worse, in Manhattan there is always someone

who leaves before the bill arrives. They'll throw down cash, half of what they owe, and then people like me,

who don’t drink, end up paying even more. But if I try to use the same trick, the hostess will shout:"Where

are you going?" And it's not like I can say I have somewhere to go: everyone know I have nowhere to go.

     But in London, dinner parties are in people's homes. Not only that, the guests are an interesting mix. The

last time I went to one, the guests were from France, India. Denmark and Nigeria; it was like a gathering at

the United Nations in New York. The mix is less striking. It's like a gathering at Bloomingdale's, a well-known

department store.

     For New Yorkers, talking about other parts of the world means Brooklyn and Queens in New York. But

at Mallery's, when I said that I had been to Myanmar recently, people knew where it was. In New York people

would think it was a usual new club.

1. What does the word"shot" in Paragraph j probably mean? [ ]

A. Choice.

B. Try

C. Style.

D. Goal

2. What does the writer dislike most about dinner parties in New York? [ ]

A There is a strange mix of people.

B. The restaurants are expensive.

C. The bill is not fairly shared.

D. People have to pay cash.

3. What does the author think of the parties in London? [ ]

A. A bit ummul

B. Full of tricks.

C. Less cosdy.

D. More interesting.

4. What is the author's opinion of some New Yorkers from her experience? [ ]

A. Easy-going.

B. Self-centered.

C. Generous.

D. Conservative.

填空题