问题 实验题

在做“描绘小灯泡的伏安特性曲线”的实验中,实验室提供了小灯泡(3.8V,0.3A)、电流表(0~0.5A,内阻约为0.4Ω)、电压表(0~15V,内阻约为20 kΩ)以及滑动变阻器(5Ω,2A)等实验器材。

(1)如果用多用电表欧姆档粗略测量该小灯泡的电阻,应选用的档位是_____________。(选填选项前面的字母)

A.×1000

B.×100

C.×10

D.×1

(2)如果既要满足小灯泡两端电压从零开始连续变化,又要测量误差较小,应从图示的电路中选择_____________电路做实验电路。(选填对应电路图下面的字母)

(3)利用实验数据画出了如图所示的小灯泡的伏安特性曲线。根据此图给出的信息可知,随着小灯泡两端电压的升高,小灯泡的电阻_____________。(选填“变大”、“变小”或“不变”)

答案

(1)D

(2)B

(3)变大

阅读理解

For 99% of human history, people took their food from the world around them. They ate all that they could find, and then moved on. Then around 10,000 years ago, about 1% of human history, people learned to farm the land.

The kind of food we eat depends on which part of the world we live in, or which part of our country we live in. For example, in the south of China they eat rice, but in the north they eat noodles. In European countries near the sea, people eat a lot of fish. In central Europe, away from the sea, people don’t eat so much fish, but they eat more meat. For example, in Germany and Poland, there are hundreds of different kinds of sausages.

In North America, Australia, and Europe, people eat with knives and forks. In China, people eat with chopsticks. In parts of India and the Middle East, people use their fingers to pick up food.

Nowadays it is possible to transport food easily from one part of the world to another. We can eat whatever we like, at any time of the year. In Britain, bananas come from Africa; rice comes from India or the U.S.A.; strawberries come from Chile or Spain. Food is a very big business. But people in poor countries are still hungry while people in rich countries eat too much.

小题1:10,000 years ago, people ______ .

A.learned to farm the land

B.cooked different kinds of food

C.couldn’t find food around them

D.transported food from one country to another小题2:In North America, Australia, and Europe, people ______ .

A.eat with chopsticks

B.eat with knives and forks

C.use their fingers to pick up food

D.use bread to pick up food小题3:______ have many kinds of sausages.

A.Chile and Spain

B.America and Australia

C.China and Japan

D.Germany and Poland小题4:Which of the following is NOT true?

A.What we eat depends on where we live.

B.Poor countries are still having food problems.

C.Rich countries don’t need food from others.

D.Nowadays we can eat whatever we like at any time of the year.

填空题