1、控制电流不变，改变匝数。 （2）探究磁性强弱与电流的关系：控制匝数不变，通过滑动变阻器改变电流。（3）探究磁性强弱与有无铁芯的关系： 控制电流和匝数不变，插入铁芯。观察线圈吸引大头针的多少。 5、将铁芯换成刚棒，开关断开后的现象。答：因为刚棒是永磁铁，断开开关后大头针不会掉下来。 6、电磁铁吸引的大头针下端分散的原因：答：同名磁极相互排斥。 九、探究电磁感应现象 1、转换法：通过观察灵敏电流计指针是否偏转来判定是否产生电流。 2、控制变量法：（1）探究电流方向与磁场方向的关系：控制导体运动方向不变，改变电流方向，观察电流计指针偏 转方向。（ 2）探究电流方向与导体运动方向的关系：控制磁场方向不
2、变，改变导体运动方向，观察电流计指针偏转方 向。（ 3）探究电流大小与磁场强弱的关系：控制导体切割磁感线运动的速度与方向不变，改变磁场强弱，观察电流计 偏转的角度。（ 4）探究电流大小与导体运动速度的关系：控制导体运动方向和磁场强弱不变，改变导体切割磁感线运 动的速度，观察电流计偏转的角度。 3、产生感应电流的条件：（1）电路必须闭合（2）闭合电路的一部分导体做切割磁感线运动。 4、能量转化：机械能转化电能 5、电流计指针不偏转的原因：（1）导体没有做切割磁感线运动（2）电路没闭合（3）产生电流太小。 物理常识与估测问题 1.一些物体的长度 物体长度 /m 物体长度 /m 中学生身高1.501
3、.80 教室长10 一张纸厚610-5 教室宽 6 课桌高度0.8 教室高3 日光灯管长1.2 篮球架的篮筐的高度3.05 2.一些物体的质量和重力 物体质量 /kg 重力 /N 一个鸡蛋510-20.5 成人5070 500700 铅球（男） 5 50 物理课本0.25 2.5 3.一些物体的运动速度 物体速度 /ms -1 人步行1.11.3 自行车5 公共汽车10 12.5 普通列车 40 声速（ 15的空气中）340 光和无线电波（真空中）3108 4.一些物体的压强 物体压强 /Pa 一个标准大气压1.013 105 一张纸平放在水平桌面上对桌面的压强0.5 7 一个中学生站立时对地
4、面的压强2.810 4 物理课本50 5.一些物体的功率 物体功率 /W 人的心脏跳动功率1.5 人跑上楼的功率300 人在平直公路上骑自行车的功率100 人做引体向上的功率24 6.一些电流、电压值 物体电流 /A 事物电压 /V 手电筒 0.3 一节干电池 1.5 家用电冰箱1.11.7 一节蓄电池2 家用空调47 家庭电路220 普通白炽灯0.10.3 人体的安全电压不高于 36 47cm 彩色电视机0.2 一般交流电动机380 7.一些电阻、电功率值 事物电阻事物电功率 /W 100W 的灯泡灯丝在室温下： 30 正常发光时：484 普通白炽灯15100 人体电阻几千电视机约 200
5、电熨斗几十空调约 1000 电饭煲几十微波炉8001000 电冰箱约 100 8.一些物体的温度 物体温度 /物体温度 / 绝对零度-273.15 地球表面最高温度63 标准大气压下水的沸 点 100 正常人的体温36.8 通 常 情 况 下 冰 的 熔 点、水的凝固点 0 人感觉舒适的温度 23 我国最低气温记录-52.3 冰箱冷冻室-18-23 地球表面最低温度-88.3 冰箱冷藏室510 物理原理与其相关的实例 原理实例 力的作用是相互的划船、游泳、走路、 重力方向竖直向下瓦工用重锤线检查墙壁是否竖直、用重锤线检查墙上的画挂的是否正、用重锤线 检查工作台面是否水平 二力平衡条件悬挂法测物
6、体的重心、用弹簧测力计测物重、测滑动摩擦力的大小 运动和静止的相对性用于通讯的同步卫星、空中加油机给正在飞行的飞机加油、宇宙飞船在空中对接、 接力赛时运动员跑起来接棒 惯性利用惯性的实例有：跳远、摩托车飞越障碍物、斧头松了斧柄在坚硬的地上撞击 几下、汽车进站前司机关闭油门让汽车慢慢停下 8 防止惯性的实例有：城市交通车辆有一定的车速限制、载重限制、交通车辆保持 一定的车距、公交车上的提示语“车启步请扶好扶手”、司机和前排乘客要系安 全带、百米赛跑终点要留有余地 增大接触面的粗糙程度增大摩擦轮胎、刀柄、鞋底上刻有凹凸不平的花纹 增大压力增大摩擦皮带打滑时用力张紧皮带、自行车刹车时用力捏车闸 变滑
7、动为滚动减小摩擦冰箱下面按装车轮、机器的转动部分用滚动轴承代替滑动轴承、搬运笨重物品时 在其下面垫圆木 给接触表面加润滑剂减小摩擦给机器的转动部分加润滑油、给生锈的锁中加铅笔芯粉末 使接触表面脱离减小摩擦磁悬浮列车、气垫船 减小受力面积增大压强刀子、斧头等锋刃要磨得很薄、锥子、钉子、针等的尖端做得很尖 增大受力面积减小压强房子的地基做得比墙后、铁路的钢轨铺在枕木上、人坐在沙发上感觉舒服、坦克 安装两条履带 液体的压强随着深度的增加而增 大 水坝的下部做得比上部宽一些、潜水艇潜入水中有一定的限度、医生给病人吊挂 生理盐水时将瓶子的位置提高一些，输水速度快一些 连通器水壶与壶嘴、锅炉与外面的水位计
8、、水塔与自来水管、船闸、过路涵洞 大气压的作用抽水机抽水、钢笔吸墨水、注射器吸药液、用饮料管吸饮料、圆顶吸盘挂钩 流速大压强小利用：“竹蜻蜓”、飞机的升力、上旋球、下旋球、香蕉球 防止：铁路站台上设置安全线、并列行驶的轮船不能靠得太近 物体的浮沉条件潜水艇的浮沉、盐水浸泡法选种、测定人体血液密度、气象站放出的探测气球 物体的漂浮条件轮船、密度计 省力杠杆撬棒、老虎钳、起子、独轮车、铁匠剪刀 费力杠杆缝纫机踏板、理发剪刀、钓鱼竿、镊子、人的前臂 等臂杠杆天平、定滑轮 声能传递信息铁路工人用铁锤敲击钢轨听声音判断螺旋是否松动、医院里的 B 超利用超声波为 孕妇作常规检查，判断胎儿的发育情况、蝙蝠靠
9、超声波探测飞行中的障碍和发现 昆虫、利用声纳探测海深和鱼群 声能传递能量利用超声波清洗钟表等精密仪器和除去人体内的结石 光在均匀介质中沿直线传播射击瞄准、木工判断木板是否刨平、站队看齐、激光准直 平面镜能改变光路的传播方向潜望镜、自行车的尾灯 凹面镜对光起会聚作用太阳灶、手电筒的反光装置 凸面镜对光起发散作用汽车的后视镜、接头或山路拐弯处的反光镜 凸透镜对光起会聚作用远视眼镜、放大镜、照相机、投影仪 凹透镜对光起发散作用近视眼镜 红外线红外线夜视仪、电视机遥控器 紫外线医院的手术室和病房灭菌、验钞机 水的比热容较大冬天暖气用水取暖、沿海地区昼夜温差小、培育秧苗时为了保护秧苗夜间不受冻 向秧田里
10、灌一些水 电流的热效应电热毯、电炉、电熨斗、白炽灯、电水壶、电烙铁 电流的磁效应电话、电铃、电磁继电器、电磁起重机 电流的化学效应电镀 (铜)、电解（水）、给蓄电池充电 电磁感应发电机、动圈式话筒 通电导体在磁场中运动电动机、动圈式扬声器 常见单位换算： 1、时间单位换算：1 年=365 天,1 天=24h,1h=60min,1min=60s 2、速度单位换算：1m/s=3.6km/h 3、体积单位换算：1m 3=103dm3, 1dm 3=103cm3 1m 3=106cm3 1L=1dm 3, 1mL=1cm 3 4、密度单位换算：1g/cm3=1000kg/m3 5、面积单位换算：1m
11、2=102dm2 1dm 2=102cm2 1m 2 =10 4cm3 6、电阻单位换算：1 兆欧 =10 6 欧姆 ,1 千欧 =1000 欧姆 7、电功单位换算：1 千瓦时 =3.6x10 6J 臮臮言臮!臮臮臮臮臮臮踀鸀!臮蠀頀餐!變臮诋臮讌臮诌臮词臮诏臮言鯫臮鮬臮鮍臮!鯝臮鯞臮輀蠐褐!臮!臮踀灰鄐瀀瀀怐脐鄀鄀鄀瀀瀰鄰瀀瀰脐怀恐瀐恠鄐瀀脐瀐脐腰脐脐怐【R安徽省2002年普通高等学校专升本招生考试英语试题I Vocabulary and Structure (1point each;35points in all )Directions：or each of the following b
12、lank1，four choices are given. You are required to choosethe most appropriate one and put the corresponding letter in the bracket before each sentence1.I wont pay them _they work harderAif Bin case Cunless Dlest2. They succeeded at last after adopting an_methodAeffect Baffect Ceffective Defficient .3
13、.My problems are very _to yours.Alike B same Cpaid Dexact4. He demanded that I_ the bill by Friday at the latestAmust pay Bpay Cpaid Dto paid 5. The population of China is bigger than _AIndia B. Indias C. the one of India D .to paid 6. When I was a child ,I_ice cream ,but I donto like it now A. used
14、 to like B,was liking C. use to like D. used to liking 7. The movie _us of the pains brought by World War IIA .was thought of B. kept C .reminded D .remembered8.New problems will_as the construction is under way A. rise B .arise C. arouse D .rouse 9.He would rather_his opportunity to study abroad ta
15、n leave the research unfinishedA, .made up B .take up C .give up D. carry out 10.I paid a visit to him last night .We had a chat _coffeeA .make up B in C. over D. by 11.David makes about 2,00a month as an engineer in a company Besides ,he has another _of income by writing technical books in his spar
16、e time A. resource B. source C. course D. result 12.Hats in this style are_ with the young people this yearA. widespread B. welcomed C. popular D .close13.It was believed there was no limit _the energy resources onour earthA. for B .off C .to D .on 14.His parents asked him to buy _books he found use
17、ful and necessary for his study A .whichever B .whatever C. whenever D. however 15.Which is your_way to travel，by plane，by ship or by car？A. favor B .favored C .favorite D. favorable 16.Computers can solve many difficult_A. files B .questions C. query D .issue 17.He has _his purpose with the help of
18、 his friendsA. files B. finished C. accomplished D. completed 18.Television can be a _for spreading informationA .middle B .medium C. media :D. ,mere19.Rodert is reliableYou can_him A. count on B. count up C .count to D. count for 20.The thought came to him _his mother had been out for several hours
19、 .A .that B. who C. which D .whom21.At that time,committee, so far as I know, _of three scientists, two professors ,and four senior engineers.A. composed B. comprised C. consisted D .made up 22.It was_then that I realiaed the importance of a good mastery of the language.A .until B. unless C. not unt
20、il D .not unless23.Ill spend more time on English_I can pass the exam easily.A. so that B .in order to C .even D. in order 24.Because of the adjustment the total output value if industry has deen _ten times .A increased B doubled C. as much as D. the size of 25.British peoele would find it difficult
21、 to _driving ,on the right .A. get accustomed to B .get along with C .make sense of D. make sure 26.The fabric is not real silk ,only an imitation. Here“imitation ”means_.A.假装 B.效法 C. 模拟 D.模仿制品27.It_have rained last night , for the ground is wet .A. will B can C .should D. must 28.They have develope
22、d techniques which are _to those used in most factories .A. more talented B .better C. greater D. superior 29.Only after a year _to see the result of my experiment.A.I began B.I had begun C. have I begun D. did I begin 30.Neither John nor his parents _at home .A ,is B. has C. are D .was 31._in the f
23、ields for two hours ,.they took a rest .A .Having worked B. Working C .Worked D Being worked 32,The soldiers marched down the street ,_their flags. A. waved B. waving C. being waved D .wave 33.Man must stop _the earths atmosphere. A. filling B. emitting C .polluting D .wasting 34.The three hours I s
24、pent in the school library _my old passion for reading .A. brought about B .brought over C. brought forth D. brought back 35.He was disappointed so often that he became _.A. hopelessness B .hopelessly C. hopeful D .hopeless II Cloze (1 point each; 10 points in all)Directions: There are 10 blanks in
25、the following passage. For each blank there are four choices marked A,B,C and D.You should choose the one that best fits into the passage and put the corresponding letter in the bracket before each choice .When people die, different cultures dispose _36_their bodies in different ways .Sometimes bodi
26、es are burned. Sometimes bodies are buried in the ground,In many _37_in the past, people were buried with food ,weapons,jewellery, and other things_38_might be useful in the next life. _39_,the ancient Egyptians buried people with little human figures _40_clay. These clay figures were supposed to wo
27、rk for the dead person in the other world.A religious group called the Parses exposed their dead on platforms for birds to eat .Some people practice _41_second burial .After the bodies_42_in the earth for several years,the bones are dug up and reburied, sometimes in a small container.These are just_43_of the many different customs that_44_in different cultures.Most of the time, the different ways that are the customs of different cultures are _45_right _45_wrong. It is simply that different people do the same things in different ways.36. A. of B. with C. from D .to 37. A cultur
