Q=I^2Rt，纯电阻电路中 可推导出 Q=日夏养花网U^2/Rt=220*220*100/10000J=484J

中考英语科模拟试题（一）
听力部分(20%)
I.听句子(选择听到的单词，完成下列句子，每个句子读2遍)。(5分)
( )1.Last I went boating with Mary.
A. Saturday B. Sunday C. Monday
( )2.Mr black lives in the part of the USA.
A. northern B. southern C. western
( )3.We often help the twins with their .
A. history B. Chinese C. English
( )4.Is grown in your hometown?
A. tea B. cotton C. rice
( )5. water, nothing can live.
A. With B. Without C. No
II．听对话(根据听到的内容，选择正确答案 )。(10分)
第一节 听下面4段对话，每段对话后有一个小题，从题中所给的A、B、C、3个选项中选出最佳答案(每段对话读2遍)。
( )1.A. It’s near here.
B. It’s at the end of the bridge.
C. It’s on the other side of the river.
( )2. She comes from .
A. America B. Australia C. England
( )3. They’ll stay here for .
A. two hours B. three hours C. four hours
( )4. They are going to pick .
A. apples and oranges B. pears and oranges C. apples and pears
第二段 听下列3段对话，每段对话后有两个小题，从题中所给的A、B、C、3个选项中选出最佳答案(每段对话读2遍)。
听第一段对话，回答5、6小题。
( )5. What are they talking about?
A. They are talking about doing some shopping .
B. They are talking about their brothers.
C. They are talking about a shirt.
( )6. What is Kate going to buy?
A. She’s going to buy a skirt. B. She’ going to buy a shirt.
C. She’s going to buy shoes.
听第二段对话，回答7、8小题。
( )7. What’s wrong with Tom?
A. He had a cough B. He had a fever. C. He hurt his leg.
( )8. What did the doctor give Tom?
A. The doctor gave him nothing. B. The doctor gave him water.
C. The doctor gave him medicine.
听第三段对话，回答9、10小题。
( )9. When was Ann’s birthday?
A. It was last Saturday. B. It was this Sunday. C. It was last Sunday.
( )10. What did Bruno give Ann as a birthday present?
A. Bruno gave her a nice radio. B. Bruno gave her a nice watch.
C. Bruno gave her a small watch.
.听短文(根据听到的内容选择正确的答案，短文3遍)。(5分)
( )1. will hold a small party.
A. Mr Jones B. Mr Brown C. David
( )2. to go to the party.
A. Mr Jones is asked. B. Mrs Jones is asked.
C. Mr Brown and his wife are asked.
( )3. The telephone is .
A. in the same office B. near the office C. beside Jones’ desk
( )4. Mr Brown spoke to on the phone.
A. Mrs Brown B. Mrs Jones C. David
( )5.——Why was Mrs Brown looking for David?
——Because she thought .
A. he went out of the house.
B. he was answering the phone .
C. he was playing games with other children at home .
笔试部分(80%)
I.词汇。 (10分)
1.根据句子意思，用适当的词填空。
1) I want to post the letter .Can you lend me a ?
2) Travelling by air is expensive, but much than by sea or by land.
3) The man jumped into the sea and towards the island.
4) Jim is weak in Chinese and maths .That makes his parents about him.
5)One of my favourite is English.
2.根据汉语提示，用词组的适当形式填空。
1) Were they (在工作)this time yesterday?
2) Please (请自用)to the mooncakes , Ann and Kate.
3) Work hard or you ’ll (落后)others.
4) It’s quite late ,but Jane is still 日夏养花网 (睡觉)。
5) There’s a bookshop (贴近)the school.
.选择填空(从A、B、C、D4个选项中，选出可以填入空白处的最佳答案)。(15分)
( )1.They a football match tomorrow, and there a basketball match tomorrow, too.
A. are going to have ,is going to have B. are going to have ,is going to be
C. are going to be ,is going to have D. are going to be ,is going to have
( )2. Do the children do every morning?
A. eye exercises B. eye exercise
C. eyes exercise D. eyes exercises
( )3.Dick learned drawing ten years ago .He’s drawn pictures since then.
A. three hundred of B. two hundreds of
C. hundreds of D. hundred of
( )4. Tom is doing homework now. Can you the radio a little , Kate?
A. turn off B. turn down C. turn on D. turn away
( )5. John always says to himself, “If I hard ,I the exam this time. ”
A. work ,pass B. work, shall pass
C. shall study ,shall pass D. worked, shall pass
( )6. A lot of trees in our city in spring.
A. plant B. will plant C. are planted D. are planting
( )7. bad weather! It’s going to rain again.
A. What B. How C. What a D. How a
( )8. Mary finds it hard a letter in Chinese.
A. writes B. write C. writing D. to write
( )9. Can you tell me ?
A. which book to choose from B. which book to choose
C. to choose which book D. how to choose book
( )10. Though it rained heavily, were still working in the fields.
A. they B. and they C. but they D. so they
( )11. —— is this sweater?
——It’s .
A. Whose, yours B. Whose, mine C. Who ,hers D. What, mine
( )12. ——Do you know ?
——She Shanghai.
A. where is Lily, has gone B. where Lily is, has been to
C. where is Lily ,has been to D. where Lily is, has gone to
( )13. ——Could you help me carry the bag upstairs?
—— .
A. Nothing at all B. It’s a pleasure
C. That’s all right D. Of course, with pleasure
( )14. —— we swim in that river?
——No, you .It’s dangerous to swim there.
A. Must, can’t B. May, mustn’t C. Can, may not D. Shall, don’t
( )15. —— Would you like another cake?
—— .I’m quite full.
A. Yes, please B. I’d like to C. No, thanks D. I don’t like it
. 口语应用(选择每组对话的正确顺序)。(10分)
( )1.1) No ,never.
2) Sorry, I have to help Dad in the garden. Let’s go tomorrow instead.
3) Have you been to the zoo?
4) OK. See you tomorrow then.
5) Shall we go to the zoo now?
A. 3)1)5)2)4) B. 3)2)1)5)4) C. 5)2)4)3)1) D. 5)1)3)2)4)
( )2.1) At six .But you’d better get there a little earlier.
2) Do you know what to do after the game?
3) When?
4) To the restaurant(餐馆) behind the park..
5)Where?
6) We’ll go out for supper.
A.2)6)3)4)5)1) B.2)4)6)3)5)1) C.5)4)2)6)3)1) D.2)6)5)4)3)1)
( )3. 1) What about a school bag?
2) Tomorrow is Children’s Day .I want to buy a present for my sister.
3) What can I do for you?
4) She has one .Oh, I’d like to buy a new pen for her. She lost her pen days ago.
5) The green one looks nice. Do you think so?
6) Yes, I’ll get it.
A.1)5)2)3)6)4) B.2)6)4)3)5)1) C.3)2)1)4)5)6) D.3)2)5)6)4)1)
( )4. 1) OK. Thanks. Bye.
2) You’d better take a bus home ,I think.
3) Why not stay a little longer?
4) You can take either Bus No.8 or Bus NO.10.
5) We’re afraid we have to go home now.
6) It’s quite late.
7) Yes. But which bus shall we take?
A.2)5)1)6)3)4)7) B.5)3)6)2)7)4)1)
C.3)6)2)7)4)1)5) D.4)1)3)6)7)2)5)
( )5. 1) Why?
2) Where’s your homework ,Jim?
3) I was ill yesterday.
4) Sorry, Mr Li .I was not here yesterday.
5) Yes ,I am, thanks. Can I bring my homework here tomorrow?
6) I’m sorry to hear that. I hope you’re better now.
7) Yes. But you’d better finish it today.
A.2)4)1)3)6)5)7) B.2)3)6)5)7)4)1)
C.1)3)2)4)6)5)7) D.1)3)6)5)7)2)4)
IV．用所给动词的适当形式填空。(5分)
The twelve-year public(公立)school education in America usually
(begin) when a child is six years old. Some school education (have)
two parts; eight years of primary school (小学)and four years of secondary school(中学).And secondary school (call)high school.
Li Mei went to America two years ago ,She (study)in a high school since then. Now she (do) well both in English and the other subjects.
V．看图写话(根据图画语境，在空格中填入适当的词，使其意思完整、语法正确，每个空格限填一个单词)。(10分)

On her way home school Li Ming saw a wallet (钱包) off a bike .She picked it up and the man ,but didn’t her. So she
The bag and found a licence and some money in it .She thought the man must the owner(失主).She decided to find him as soon as possible. About half an hour later ,she got to the man’s house and gave the
back to him .He said thanks to her.
VI．完形填空(从每题4个选项中选择可以填入空白处的最佳答案).(10分)
Different people speak different languages, but 1 have a language of their own .Anyone can play. A player’s native(本国的)language is not 2 .A football player from Japan can play with a player from England. One does not
3 to understand the langrage of the other .The game 4 for them.
People who do not know each often become friends after they have played together. The new boy 5 girl in school quickly becomes one of the class after a few 6 .The new person on the job(工作)feels 7 after he or she played basketball with other people on the playground .People in different parts of the world learn to 8 one another through sports.
Whether in the stadium(运动场)or in other places ,people always 9 sports. They will change the rules(规则),invent new games, and forget some games, but they will never stop playing .Sports make 10 more interesting.
( )1.A.animals B. birds C. men D. sports
( )2.A.difficult B. easy C. good D. important
( )3.A. hate B. like C. need D. want
( )4.A. cares B. looks C. speaks D. wants
( )5.A.or B. but C. and D. with
( )6.A. games B. lessons C. minutes D. things
( )7.A.better B. sorry C. tired D. worse
( )8.A.look after B. help C. remember D. understand
( )9.A.change B. enjoy C. learn D. understand
( )10.A. game B. life C. people D. player
VII．阅读理解(根据短文内容，从每小题 A、B、C、D中选择一个最佳答案)。(15分)
A
When you are reading something in English ,you may often meet with a new word. What’s the best way to know it?
You may look it up in an English-Chinese Dictionary. It will tell you a lot about the word ,the pronunciation(语音),the part of speech(词性),the Chinese meaning and also how to use this word. But how can you know where the word is in www.rixia.ccso many English words? How to find it in the dictionary both quickly and correctly(准确地)?
First, all the English words are arranged in the alphabetical order(按字母顺序排列)。In the dictionary you can first see the word ,beginning with the letter A、B、C、D……That means, if there are two words,“monitor”.Then if there are two words both beginning with the same letter ,you may look at the second letter ,then the third, the fourth…For example,“before”is before“begin”,“foreigner”is before“forest”.
Do you understand how to look up a word in a dictionary ?The dictionary will be your good friend. I hope you’ll use it as often as possible in your English learning.
( )1.According to(根据)the passage, if we don’ t know a word ,we’ d better
.
A. think hard B. write it again and again
C. ask our teacher or classmates D. look it up in a dictionary
( )2.When you look up a word in the English-Chinese Dictionary ,you should understand its Chinese meaning and .
A. its pronunciation B. its part of speech
C. the use of it D. A, B and C
( )3. In the English-Chinese Dictionary ,the first part is .
A. the words beginning with the letter A
B. the words beginning with the letter B
C. the simple words
D. the very short words
( )4. Here are four words :(1) regular (2) relative (3) reject (4)religion
The right order in the English-Chinese Dictionary is .
A.(1)(2)(3)(4) B.(1)(3)(2)(4) C.(2)(3)(4)(1) D.(3)(1)(4)(2)
( )5. The English-Chinese Dictionary is .
A. useful in our Chinese learning.
B. our good friend in learning Chinese
C. a good friend in our English learning
D. not useful in learning English
B
An English traveler found himself in a northern European(北欧)country with a little money to buy the ticket for the travel back home. As he knew that it would take him only two days to get to England, he found that he world be all right without food. So he bought a ticket and got on the ship .He closed his ears to the lunch bell .When dinner time came ,he didn’t go to breakfast and at lunch time he again stayed in his room .At dinner time he was so hungry that he could not stand(忍受) it any longer.“I’m going to eat ,”he said,“even if they throw me into the sea.”At dinner he ate everything in front of him at the table ,and waited for the coming trouble.“Bring me the bill (账单),”he said .“There isn’t any bill ,”was the answer .“On the ship the money for the ticket includes(包括) meals,”the waiter(侍者) said to him.
( )6. An English traveler decided to go back home .
A. by air B. by sea C. by car D. by land
( )7.The Englishman closed his ears to the lunch bell because .
A. The meal was too expensive B. he was not feeling well
C. he wasn’t hungry at all D. he hadn’t enough money
( )8. Altogether (总共)the Englishman spent about day(s)without food.
A. one and a half B. two C. one D. none of the above
( )9. At last he went to have the meal at dinner time because .
A. he was told that the money for the ticket included meals.
B. he had borrowed some money from his friends
C. the dinner was very cheap and delicious
D. he couldn’t stand his hunger any more
( )10.When he knew he needn’t pay any money for the meal ,the English -man must be .
A. very angry B. very sad C. very glad D. very lucky
C
They English language we know today is about six hundred years old. For half that time, English was just the language of the English living in English living in England. The modern English language grew by about the year 1,400.Many words were borrowed from French and German.
As people from Europe(欧洲) traveled outside Europe. European languages began to be used in other parts of the world .At first, the languages stayed the same as those in Europe ,but slowly they began to grow apart(产生差异).
Today ,the differences between American English and British English are not very great. Written English is more or less the same in both Britain and America, though there are some spelling differences. For example, center, colour , and traveled are spelt as center ,color and traveled in American English .But people from the two countries can understand each other easily.
Though the English passed their language on to North America, these days ,the British have borrowed a lot of new words from the Americans, such as teen-ager, boyfriend ,radio, footballfan, right away, and so on.
There are only a very small number of differences in grammar in American English and British English . The most important differences are in spoken English.
You may wonder“Which is correct?”The answer is that it does not matter .But you Should speak either American English or British English .Do not try to speak both at the same time.
( )11. English was just the language of the English people for about
years.
A. 600 B. 300 C. 1,400 D. 5,000
( )12. As Europeans traveled outside Europe ,they .
A. passed their languages to the other parts of the world
B. spoke their languages in the other parts of the world
C. used French and German
D. have known many languages
( )13. Written English is in both Britain and America.
A. all the same B. not the same
C. almost the same D. quite different
( )14. Today ,the British .
A. have borrowed a lot of new words only from the German
B. have borrowed some new words only from the French
C. have borrowed a lot of new words from the French ,German and the Americans
D. will have to use American English out of their homeland.
( )15. When we speak English, we should .
A. speak either the British English or the American English.
B. speak the two at the same time.
C. speak only the American English.
D. tell the differences between American English and British English.
VIII.书面表达。(5分)
假设你是凯特，两个朋友前来到中国北京。2001年5月25日你写信给美国
的朋友安，告诉她一些有关中国、中国人民及中国食物的情况，请她早日到中国参观。
要求：写50—70个词；文字通顺、准确；把所给的词都用上。
Two months since come China beautiful country with places of interest Chinese people great invent many things they friendly to us Chinese food delicious like very much hope visit China

电功、电功率、焦耳定律、生活用电中考试题分析
随着中考改革的不断深入，近年来物理中考试题与前些年相比，有很大的变化。突出表现在具有鲜明的物理学科特色。

对于中考试题的研究我们可以从试题的解题思路、解题方法、易错之处进行研究。通过对近三年试题的研究，我认为一些被大家称为“热点”的试题可以分为四类：常规题、创新题、实验题。下面对这三类题做一个简要分析。

一、 常规题

这类试题在全国各省市的中考试题的全卷中占有比例大约为70%。按照解题过程可以将这类试题分为二类：一类是试题只涉及一个物理过程，一个计算公式。如：海淀2002中考试题28题、小李同学自制了一个简易“电热驱蚊器”，它的发热元件是一个阻值为1.0104欧的电阻。将这个电热驱蚊器接在电源的两端，当电源两端电压为220伏时，100秒内产生的热量为 焦。这类试题主要考查学生基础知识、基本技能的掌握情况。包括学生对知识的一般认识、基本的计算能力等。要求学生对所学知识有一个较全面的认识。

另一类是试题涉及两个以上物理过程，或多个状态，多个公式。

这类试题主要考查学生的分析问题的能力和解决问题的能力。这类试题要求学生思路清晰，教师在教学中应引导学生学会如何解决这类复杂问题。使学生掌握解题的一般过程：审题、解题、验证。审题要做到物理情景、物理过程清晰，变量、不变量清晰，状态量与过程量之间的关系清晰，并能利用情景图将其中的关系反映出来。如：2001年中考副题：如图所示是电饭锅加热和保温时的电路示意图。设加热时的功率为1100瓦，保温时功率为5瓦。

（1）用学过的公式推理说明，电饭锅处于加热状态时，开关S是断开还是闭合？

（2） R2的阻值为多大？

（3） 用此电饭锅把2.5千克水

从20℃加热到90℃需要最短时间是多少？

二、创新题

这类试题在中考试题中从考查作用看处在较高能力考查地位。突出对学生收集和处理信息的能力、分析和解决问题能力、语言表述能力、数理推导能力等较高能力的考查。

主要有几种形式：

1、在新情景下解决问题。如2002年海淀区中考试题33．在相距20千米的甲、日夏养花网乙两地之间有两条输电线，已知输电导线每米长的电阻为0.01欧。现输电线在某处发生短路，为确定短路位置，检修员利用电压表、电流表和电源接成如图20所示电路进行测量。当电压表的示数为1.5伏时，电流表的示数为30毫安，则可确定出短路位置离甲地 千米。

本题是考查欧姆定律的试题，但在新情景下出现，就增添了难度。

31．一个额定功率为1瓦的玩具电动机，正常工作时在2秒内将150克的钩码匀速提高1米，则此装置的效率是_____。（g取10牛/千克）

某校食堂有一台小型锅炉，锅炉铭牌如下表，烧锅炉师傅还提供了如下数据：

你去学海载舟上的模拟考场吧。那里有专项训练的（阅读理解、完形填空、填空），而且是自动评分的,也有答案对照

焦耳定律练习题
1、小明在科技实践活动中需要一只150的电阻，可手边只有600、200、120、80、70、30的电阻各一只，他可用 两只电阻 联代用，也可用 两只电阻 联代用。
2、标有“220V 40W”的电烙铁，接在220V的电源上，该电烙铁每分钟产生的热量是 J，1h消耗的电能是 kwh.
3、有甲、乙两只电炉，已知电炉电阻R甲>R乙，现将两只电炉分别接入电源电压为220V的电路中，在相同时间内，通过两电炉的电阻丝的电流I甲 I乙，两电炉的电阻丝放出的热量Q甲 Q乙。（均选填“>”、“<”或“=”）
4、小李同学自制了一个简易“电热驱蚊器”，它的发热元件是一个阻值为1.0104的电阻。将这个电热驱蚊器接在220V的电源上，100s内产生的热量是 J。
5、一电热器电阻丝的电阻为120，接在220V的电路中，要产生3.63105J的热量，需通电 min。
6、将一台“220V 100W”的电风扇、一个“220V 100W”的充电器、一把“220V 100W”的电烙铁分别接到220V的电源上，在相同时间内，通电后产生热量最多的是（ ）
A、电烙铁 B、充电器 C、电风扇 D、一样多
7、在相同时间内，电流通过电阻丝甲产生的热量比通过电阻丝乙产生的热量多，则下列说法正确的是（ ）
甲的电阻一nmPtEaR定大于乙的电阻
甲两端的电压一定大于乙两端的电压
甲中的电流一定大于乙中的电流
甲的实际功率一定大于乙的实际功率
8、把两全相同的电阻丝串联后接在电压为U的电源 上，它们在时间 t内产生的热量为Q1；若把它们并联起来接在同一电源上，在相同的时间内产生的热量为Q2，则
( )
A、Q1∶Q2＝1∶4 B、Q1∶Q2＝4∶1 C、Q1∶Q2＝1∶2 D、Q1∶Q2＝2∶1
9、在验证焦耳定律的实验中，为了比较电流通过两根不同的电阻丝产生的热量跟电阻的关系，实验时应同时保持相同的物理量是（ ）
通过它们的电流和加在两端的电压
通过它们的电流和它们的电阻
通过它们的电流和通电时间
通过它们的电流、加在它们两端的电压及通电时间
10、电熨斗通电生很烫，而连接电熨斗的导线却并不怎么热，这是因为（ ）
导线不绝缘保护层，能隔热
导线散热快，所以温度低
通过导线的电流小于通过电熨斗的电流
导线电阻小产生的热量少
11、为了使电热器的功率变为原来的一半，下列办法中正确的是（     ）
A、保持电压不变，电阻变为原来的一半；
B、保持电阻不变，电压变为原来的一半；
C、电压和电阻都变为原来的一半；
D、使电压变为原来的1/4，电阻变为原来的一半
12、用电热丝烧水，当电压为U时，t秒内可将水烧开.如果电压降为原来的一半，则同样烧开这些水所需的时间应为 ( )A．t／4 B．t／2 C．2t D．4t
13、有一只电烙铁，如果在同一个家庭电路里，要使它在相同的时间内产生的热量少些，下面几种改装方法可行的是：( )
A．把电阻丝剪去一小段。 B．更换一根较粗的电阻丝。
C．与电阻丝串联一个电阻。 D．与电阻丝并联一个电阻
14、电动汽车成为未来汽车发展的方向。若汽车所用电动机两端的电压为380V，电动机线圈的电阻为2，通过电动机的电流为10A，则电动机工作10min消耗的电能为多少焦？产生的热量是多少焦？

15、有一个电路，电阻R和小灯L串联在电源两端.电源电压为15V，已知电阻R=3，且R在电路中1s内产生的电热为27J,.灯L的额定功率为32W，求： 
（1）小灯泡的阻值.
（2）小灯泡的额定电压.
（3）小灯泡在电路中实际电功率

16在研究焦耳定律的演示实验中，
（1）（本题各空均选填“相同”或“不同”）为了研究电流通过导体放出的热量与电阻的关系，两烧瓶中煤油的质量应__________，通过两烧瓶中两根电阻丝的电流应__________，两烧瓶中两根电阻丝的阻值应__________。
(2)该实验采用的研究方法是：__________（选填“A”或“B”）。
A、与研究欧姆定律的控制变量法相同
B、与研究合力与分力关系的等效法相同

ABC与ADC并联
第一种情况:将A。C
两点
接入电路中，此时，A.C两点等分
圆周长
，ABC
长度
与ADC长度相等，由
电阻定律
知，ABC的
电阻
与ADC的电阻相等，通过的
电流
也相等，若通过ABC的电流为I1，ABC的电阻为R，则环的
电功率
P=2(I1^2)R
第二种情况:将A。D两点接入电路中，此时ABC的长度为AD的三倍，则ABC的电阻为AD的三倍，若通过ABC的电流为I2则通过AD的电流为3I2，则电功率P=3(I2^2)R+(3I2)^2R=12(I2^2)R，故2(I1^2)R=12(I2^2)R，所以
I1/I2=√6

“电热驱蚊器”就是将电能转化成内能，利用了电流的热效应工作．
当发热元件两端的电压为220V时，流过该元件的电流为I=UR=220V1.0104 =0.022A=22mA．
 通电100s产生的热量为Q=UIt=220V0.022A100s=484J．
故答案为：热；22；484．

1.（09嘉兴）5月20日是“中国学生营养日”，学生的膳食结构越来越受到学校、家庭和社会的重视。妈妈为了改善小红的早餐营养，买了一台全自动豆浆机，豆浆机的工作原理示意图和铭牌如下：

(1)计算豆浆机正常工作时的最大电流。
(2)豆浆机做一次豆浆，若电动机累计工作3分钟，电阻丝累汁加热12分钟，则总共消耗多少电能?
①3.64A②60300J

2.（09自贡）（6分）如下图所示，标有“6V、3W”字样的小灯泡与最大阻值为10的滑动变阻器串联在电路中。当变阻器连入电路中的电阻为6时灯正常发光。（不考虑灯泡电阻受温度影响，电源电压不变）求：
（1）灯泡电阻、电源电压；
（2）灯泡正常发光1min，变阻器产生的热量。
①12 9V
②90J

3. (09重庆)爱思考的林刚利用图16所示的电路进行实验，当闭合开关S后，发现标有“6V 3W”的灯L1和标有“12V 3W”的灯L2亮度并不相同。已知电源电压为6V，不考虑灯丝电阻值随温度的变化。求：
（1）通过灯泡L1的电流为多大？
（2）灯光L2每分钟消耗多少电能？
（3）灯泡L2的实际功率是多大？电路中灯L1和L2哪个更亮？
①0.5A
②45J
③0.75W L1
4. (09常德)如图所示，电源电压U=18V，当滑动变阻器的滑片P移至最左端时，小灯泡L正常发光，电流表的示数为0.5A； 当滑片P移至中点时，电流表的示数变为0.25A。
求：（1）小灯泡的额定功率；
（2）滑动变阻器的最大阻值。
①9W
②72
5. (09安溪)如图25所示电路中，电源电压保持6V不变。
（1）当闭合开关S，断开开关S1时，电流表的示数为0.1A，求电阻R2的阻值；
（2）当同时闭合开关S和S1时，电流表的示数为0.3A，求电阻R1消耗的电功率。
①60
②1.2W

6.（09綦江）如图13所示，小灯泡L上标有“6V 3W”字样，定值电阻R=6W，当开关S闭合时，小灯泡正常发光。
求：(1)小灯泡正常发光时的电流；
(2)定值电阻两端的电压；
(3)定值电阻R在l0s内消耗的电能
①0.5A
②3V
③15J
7.（09太原）在图16所示电路中，电源电压保持不变，定值电阻R1＝10, R2为滑动变阻器。闭合开关S，当滑片P在a端是，电流表的示数为0.3A；当滑片P在b端时，电压表示数为2V．
求：（1)滑动变阻器R2的最大阻值？
（2）当滑片P在b端时，定值电阻R1消耗的电功率是多大？
①20
②0.1W

8.（09泰安）右图是某品牌家用电饭锅的工作原理图，已知R2 的阻值为44；单独闭合开关S1时，电饭锅处于保温状态，此时的保温功率为40W。求：
（1）R1阻值是多少？
（2）同时闭合开关S1、S2，电饭锅工作1min消耗多少电能？
①1210
②68400J

9.（09襄樊）如图11所示的电路中，R1＝6，R2＝20，R3＝30，电源电压保持不变。当S1、S2都闭合时，电流表的示数是0.6A，求：
(1)电源电压是多少?这时R2中的电流是多少?
(2)当S1、S2都断开时，1分钟R1产生的热量是多少?
①18V 0.9A
②90J

10.（09河北）小明学了家庭电路知识后，利用电能表和秒表测量家中电热水器的实际功率。他的做法是：打开标有“220V 1210W”的热水器，关掉家里的其他用电器，测得电能表（标有“1800r/Kw•h”）的铝盘转过200转所用的时间是400s。（热水器电热丝的阻值不变）
求：（1）热水器的实际功率。
（2）通过热水器的电流。
（3）图19是小明家的供电线路。已知此时供电站输出的电压是220V，则供电站距他家多远？（已知每千米导线的电阻为5）①1000W
②5A
③400米
11.(09雅安）小刚同学家有一台电热水器，铭牌如下表所示。

根据铭牌所提供的信息，求：
（1）该电热水器电热丝正常工作时的电阻是多大？
（2）（2分）电热水器正常工作持续45min产生的电热是多少焦？
（3）若夏天用电高峰时家庭电路的实际电压只有198V，不考虑电热丝电阻随温度的变化，则电热水器在用电高峰时的实际功率为多少？（2分）
①24.2
②5400000J
③1620W
12.(09天津)图13是某简易电吹风工作原理的电路图(R为电热丝，M为电动机)，表3是该电吹风的铭牌。求：

(1)电吹风正常工作且吹热风时，流过电热丝的电流多大。
(2)电热丝R的阻值多大(电热丝的阻值随温度变化不计)。
①2A
②110
13.（09兰州）某同学发现深夜家里的台灯比傍晚时要亮，学习了电功率的知识后，他知道这与电灯两端的电压有关系。但家中没有电压表，他借助家中的电能表测得，傍晚只亮这盏台灯时，在4min10s内电能表的转盘转了2转，电能表的铭牌如图23所示，电灯的铭牌上标有“220V 25W”的字样。请你帮他估算出此时：
（1）台灯两端的实际电压和实际功率；
（2）说明在此估算过程中用到了哪些近似？
①176V 16W
②
14.（09朝阳）某种型号的电烤箱有高、中、低三个档位的发热功率。图12是其内部简化电路图，开关S1可分别与触点a、b接触。已知：R1= 60，R2 =120，电源电压为220V。
(1)当S1与a接触、S2闭合时，通过电热丝的总电流是多少？
此种接法属电烤箱的什么档位？
(2)求电烤箱处于另两个档位时发热功率的比值是多少？
①5.5A
②9：2
15.（09绵阳）现代生物医学研究使用的细菌培养箱内的温度需要精确测控，测控的方法之一是用热敏电其余阻来探测温度。如图甲所示的电路，将热敏电阻Ro置于细菌培养箱内，都置于箱外。这样既可以通过电流表的示数来表示箱内温度，又可以通过电压表的示数来表示箱内温度。已知该电路中电源电压是l2 V，定值电阻R的阻值是200 。热敏电阻Ro的阻值随温度变化的关系如图乙所示。求：
(1)当培养箱内的温度降低时，电流表的示数如何变化？
(2)当培养箱．内的温度为40℃时，电压表的示数是多大？
(3)已知电流表的量程是0 ~30 mA，电压表的量程是0~8 V，则此电路能够测量的最
高温度是多大？此时热敏电阻Ro消耗的电功率是多大？

①降低
②4V
③60 0.18W
16.（09贵阳）如图20甲所示，当开关S接a时，移动滑动变阻器的滑片P，根据测出的电流、电压值，画出了定值电阻R0的U—I图像；当开关S接b时，同样根据测出的电流、电压值，画出了灯泡L的U—I图像，如图20乙所示。
（1）求定值电阻R0的阻值；
（2）将R0与灯L串联接在6V的电源两端时，求灯丝的实际电阻值；
（3）将R0与灯L并联接入电路并调节电源电压，当 R0消耗的电功率为4.9W时，灯L恰好正常发光，求灯L的额定电功率。

①10②5③5.25W

17．（09•淄博）如图所示，小王同学自制了一个调温电热驱蚊器。它的发热元件R1是一个阻值为35的电阻，R2是“O—50”的滑动变阻器，电源电压是12V。当开关S闭合后，求：
(1)变阻器滑片P滑动到a端时，电路中的电流；
(2)变阻器滑片P滑动到R2中点时，R1两端的电压；
(3)发热电阻R1的最大功率。(计算结果精确到0.01)
①0.14A
②7V
③4.11W

第一卷