问题 探究题

小华同学要做“测量小灯泡的功率”的实验,请你跟随小华边实验边思考,逐一回答下面的几个问题。

(1)请在方框内画出该实验电路图。

(2)小华刚连接完最后一根导线,立即看到灯泡发出明亮的光。在一旁观察的小雨一惊,提醒小华实验中有问题。小华想,我的实验连线没有出问题啊!请你帮助小华找出实验中两个操作不当之处:①_____________________;②_______________________。

(3)做完实验后,小华将“测量小灯泡的功率”实验与以前做过的“伏安法测量小灯泡电阻”的实验进行比较,发现这两个实验有许多相似的地方,也有不同之处。请你写出一个不同之处:_______________。

(4)小华根据测量灯泡实际功率的多组实验数据,作出了,I-U图象,如下图所示。结果发现图线不是直线,这表明灯泡的电流与电压不成正比。小华很纳闷,请你帮助他分析原因

答案

(1)“略”

(2) 连接电路过程中开关没有断开 滑动变阻器没有置于阻值最大处(答案不唯一)

(3)原理不同 (答案不唯一)

(4)小灯泡灯丝的电阻不是定值,随着温度的升高而增大 (答案不唯一)。

完形填空

阅读理解。

     New York is a very large city with 8 million people. How do so many people move about the city on their

way to work and school? So, we should know something about its transport.

     In New York you can travel about the city by subway, bus, taxi and car. The subway runs on the railroad

lines under the city. It crosses the city at different points and goes to all parts of the city. Traveling by subway

is the fastest way to get around the city.

     The second way to travel around the city is by public bus. It's a slower way to travel. This is because the

bus moves in road traffic which is often heavy.

     You can also travel around the city by taxi. This is the most expensive way, but the taxi will take you to the

very place you wish to go to. If traffic is heavy, the taxi will be slow. During the mornings and afternoons,

there is the "rush hour". This is the time when the traffic is very heavy with people going to and from work.

     The last way to get around New York is using your own car. However, it's not easy for you to drive,

especially when you are driving in the "rush hour". If there is an accident on the road, you will have to wait for

a long time.

     The best time to travel around the city is from 9 a.m. to 4 a. m. This is the time after the morning "rush

hour" and before the evening "rush hour". Traffic will be less crowed because most people are already at

school or at work.

1. The text is mainly about _____.

A. the weather of New York

B. the transport in New York

C. the people in New York

D. traffic accidents in New York

2. The fastest way to travel in New York is by _____.

A. subway

B. taxi

C. bus

D. car

3. The most expensive way to travel in New York is by _____.

A. subway

B. taxi

C. bus

D. car

4. The phrase "rush hour" in the fourth paragraph means "_____" in Chinese.

A. 比赛中的冲刺时刻

B. 一小时内所跑的路程

C. (上下班)交通高峰时刻

D. 匆匆忙忙的一小时

5. It you travel around New York in your own car, which of the following is the best time?

A. From 8 a. m. to 10 a. m.

B. From 3 p. m. to 5 p. m.

C. From 10 a. m. to 5 p. m.

D. From 10 a. m. to 3 p. m.

单项选择题 A1型题