最新透镜说课材料.doc

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1、光心：凸透镜的中心O点是透镜的光心。焦点：平行于主轴的光线经过凸透镜后会聚于主光轴上一点F，这一点是凸透镜的焦点。焦距：焦点F到凸透镜光心O的距离叫焦距，用f表示。物距：物体到凸透镜光心的距离称物距，用u表示。像距：物体经凸透镜所成的像到凸透镜光心的距离称像距，用v表示。1/u（物距）+1/v（像距）=1/f（透镜焦距）　　（关于符号的正负：物距ｕ恒取正值。像距ｖ的正负由像的实虚来确定，实像时ｖ为正，虚像时ｖ为负。凸透镜的ｆ为正值，凹透镜的ｆ为负值。）物距(u)像距(v)倒、正大、小虚、实应用u>2ff

2、　f2f倒立放大实像投影仪；幻灯机u=fv=∞不成像//　uu正立放大虚像放大镜语法及练习1be动词Be动词的用法：(1)Am--wasIs--wasAre--were口诀：我用am,你用are,is用在他她它，复数全用are。(2)肯定和否定句Iam(not)fromLondon.Heis(not)ateacher.Sheis(not)inthediningroom.Myhairis(not)long.Hereyesare(not)small.(3)一般疑问句AreyouaChinese?Yes,Iam.No,Iamn’t.Areth

3、eyAmerican?Yes,theyare.No,theyaren’t.Isthecatfat?Yes,itis.No,itisn’t.用恰当的be动词填空。1.I______aboy.______youaboy?No,I_____not.2.Thegirl______Jack'ssister.3.Thedog_______tallandfat.4.Themanwithbigeyes_______ateacher.5.______yourbrotherintheclassroom?6.Where_____yourmother?She______athome

4、.7.How_______yourfather?8.MikeandLiuTao______atschool.9.Whosedress______this?10.Whosesocks______they?11.That______myredskirt.12.Who______I?13.Thejeans______onthedesk.14.Here______ascarfforyou.15.Here______somesweatersforyou.16.Theblackgloves______forSuYang.17.Thispairofgloves______

5、forYangLing.18.Thetwocupsofmilk_____forme.19.Sometea______intheglass.20.Gaoshan'sshirt_______overthere.21.Mysister'sname______Nancy.22.This______notWangFang'spencil.23.______DavidandHelenfromEngland?24.There______agirlintheroom.25.There______someapplesonthetree.26._______thereanyki

6、tesintheclassroom?27._______thereanyapplejuiceinthebottle?28.There_______somebreadontheplate.29.There_______aboy,twogirls,threemenandtenwomeninthepark.30.You,heandI______fromChina.