问题 实验题

小华班上正在学习用电池组(电压为3V)、电压表、电流表和滑动变阻器等实验器材,测量标有“2.5V”字样小灯泡的电功率.

(1)如图所示是小华连接的实物连接图,其中有一处连接错误,请在错误连线上打“×”,并用笔画线代替导线画上正确的连线.

(2)还有一位同学由于连接电路错误,在移动滑动变阻器的触头时,发现一只表的示数增大而另一只表的示数减小,其故障可能是:______________________________.

(3)排除故障后,小华通过实验得到的实验数据如下表.请你帮助小华计算、分析实验数据.

电压U/V0.51.01.52.02.52.8
电流I/A0.080.100.140.180.200.22
功率P/W      
小灯泡的亮度不发光很暗较暗较亮正常发光强烈发光
①小灯泡L的额定功率为__________W.

②小灯泡消耗的功率与其发光亮度之间的关系是____________________.

③小华通过表中的数据,求出了灯泡在不同发光状态下的电阻值,发现这几个电阻值相差较大,其主要原因是________________________________________.

答案

(1)

(2)电压表测量的是滑动变阻器两端的电压(3)①0.5②实际功率越大,亮度越亮③灯丝温度升高,电阻变大

题目分析:(1)滑动变阻器不能同时接下面两个接线柱,应接一上一下的方式进行连接,如下图所示.

(2)电压表测灯泡两端电压时,移动滑动变阻器的触头,电路中的两只表示数都变大或都变小,不会出现一表示数变大,而另一表示数减小的情况;如果移动滑动变阻器的触头时,发现一只表的示数增大而另一只表的示数减小,可能是电路连接错误,电压表与滑动变阻器并联,电压表测滑动变阻器两端电压.

(3)①灯泡电压为额定电压U=2.5V时的功率为额定功率,由表知U=2.5V所对应电流I=0.20A,灯泡的额定功率P=UI=2.5V×0.20A=0.5W.②分析表中数据可知,小灯泡消耗的功率与其发光亮度之间的关系是:小灯泡的实际功率越大,亮度越亮.③不同状态下,功率不同,灯丝的温度不同,灯丝电阻不同,这表明灯丝电阻受温度影响.故答案为:(1)电路图如图所示.(2)电压表测量的是滑动变阻器两端的电压(3)①0.5②实际功率越大,亮度越亮③灯丝温度升高,电阻变大.

完形填空

第二节 (共5小题;每小题2分,满分10分)

下面材料是普林斯顿大学新生入学手册中为大学生提供咨询和服务部门的介绍。请仔细阅读材料,从所给的六个选项(A、B、C、D、E和F)中,选出符合61—65各小题要求的最佳选项,并在答题卡上将该项涂黑。选项中有一项为多余选项。

A. Career Services (Room 113)

The staff of the Career Services center advise students on career choices and applications for higher education . They also help students and graduates apply their academic and life experiences to achieving career fulfillment, provide them with the services and resources necessary to make better informed career decisions and help them develop the skills necessary to progress their career plans.

Opening Hours: Monday through Friday: 8:30 am –4:30 pm

Phone : (412) 396-6644

Fax: (412) 396-6644

B. The Accommodation Office ( Room 114)

The Accommodation Office is the place to find everything concerning accommodation during your studying at this university. It offers a free advisory service and a wide range of handbooks and checklists covering the full range of housing available. In addition to this, the office also offers other services ,such as the allocation of places in local residences and the provision of information regarding privately owned accommodation.

Opening Hours: Monday through Friday: 1:30 pm –4:30 pm

Phone : (412) 396-6754

Fax: (412) 396-6752

C. Medical Center (Room 115)

The staff of the Medical Center aim to provide convenient and comprehensive medical care to students and staff of the university. The center is well equipped and the staff here are trained to deal with a broad range of medical problems. Both female and male doctors as well as nursing staff are available for consultation. Also, all kinds of medicines are sold here and are cheaper for students than other drugstores.

Opening Hours: 24 hour from Monday to Sunday

Phone : (412) 396-6649

Fax: (412) 396-6648

D. The sports office (Room 207)

Sport and recreation play an important role in the lives of students. The university has lots of indoor and outdoor sports facilities and all students are encouraged to participate in some form of sport and recreation. This office can provide information about sporting and activities to keep you fit.

Opening Hours: Monday through Friday: 7:00am-10:00pm

Phone : (412) 396-6877

Fax: (412) 396-6876

E. Food service (Room 127)

Tasty , nutritious meals and a wide variety of smacks are available from the cafeterias on campus. Maybe you are not familiar with different cafeterias here and find it difficult to get a good meal. Don’t worry! The Food Service can provide you with specific information on the food available here and offers meal plans based on your individual needs.

Opening Hours: Monday through Friday: 2:30pm-5:30pm

Phone : (412) 396-6899

Fax: (412) 396-6890

F. Library (Room 215)

There are various books and reference materials in every subject here including literature, art and math. Besides books, there are also photo-copying, video, audio-visual and computing facilities. Our collection is big and our main task is to help you solve problems on making use of the library.

Opening Hours: Monday through Friday: 8:30am-5:30pm

Phone : (412) 396-6312

Fax: (412) 396-6706

下面是一些学生的信息, 请匹配他们要选择的服务部门。

61. Richard is a foreign student majoring in medicine. He can adjust himself to the weather but he is having a lot of difficulty in getting used to the diet at the college cafeterias.

62. John is fond of sports. He plays football every day. Unfortunately, he injured his leg while he was playing this morning. He urgently needs some medical help.

63. Lucy is a new student from Washington, and she often arrives at the college late since she lives far away from the university, so she desperately needs to find a new place to live in.

64. Alice is going to leave university next year. She is preparing her papers and has to do a lot of research. She would like to find books on literature and learn how to use the audio-visual facilities.

65. Rosemary studies in the department of computer science. She is really interested in this field, so she plans to be engaged in this booming industry after her graduation, but before she makes a final decision, she wants to consult experienced teachers.

单项选择题