问题 计算题

如图是一个电热毯电路原理图。是R0是电热毯中的电阻丝,R是与电热毯电阻丝串联的电阻,电热毯上标有“220V 100W”字样,S是控制电热毯处于加热状态或保温状态的开关。

(1)用学过的公式推理说明开关S断开时,电热毯是处于加热状态还是保温状态?

(2)若要求在保温时电流通过电阻丝R0每秒钟有1J的电能转化为内能,电阻R的阻值应是多大?

答案

(1)保温状态

(2)4356Ω

阅读理解

Reading newspapers has become an important part of everyday life. Some people read newspapers as the first thing to do in the morning. Others read newspapers as soon as they have free time during the day so that they can learn what is happening in the world.

Sometimes, we do not have enough time to read all the news carefully, so we just take a quick look at the front page. At other times, we may be in such a hurry that we only have a few minutes to look at the headlines (标题) of the passage.

Newspapers can be found everywhere in the world. We can get many different kinds of newspapers in big cities, but in some mountain villages we can see few newspapers.

Some newspapers are published (出版) once a week, but most of the papers are published once a day with many pages, some even published twice a day! You know different people enjoy reading different newspapers. Some like world news, and others prefer short stories. They just choose what they are interested in.

Today newspapers in English have the largest numbers of readers in the world. The English language is so popular that many Chinese students are reading English newspapers such as China Daily or 21st Century. Also they bring us more and more information with Internet.

小题1: People read newspapers in order to ________________ .

A.learn the latest news

B.meet their own different needs

C.read the short stories

D.find the morning news小题2:From the passage we can see that           when people get newspapers.

A.they read them very carefully

B.they just read the headlines

C.not everyone reads all the pages

D.they have no time to read them小题3: Newspapers have so many pages because __________ .

A.more and more people like to read them

B.people enjoy reading something different

C.newspapers become cheaper

D.more pages mean more money小题4: Newspapers ______________ are the most popular in the world.

A.in English

B.in Chinese

C.in other language

D.with many pages小题5:According to the passage, besides newspapers, people also get information from _______.

A.magazines

B.Advertisements

C.e-mails

D.Internet

单项选择题