问题 填空题

通电螺线管的外部磁场分布与 ______磁铁的磁场分布十分相似,它的磁极可以用 ______定则来判定.

答案

由课本实验知,通电螺线管的周围小磁针的排布情况与条形磁铁的排布情况一致,所以可以确定其周围的磁场与条形磁铁的磁场一致;

根据课本关于电磁铁的基础知识可知,螺线管的磁极是由电流方向、线圈绕向来确定的.要用安培定则来判定.

故答案为:条形;安培.

写作题

书面表达

         假如你是李雷,你收到英国朋友Jack的一封信,他希望交一些中国笔友。你给他写一封回信,将你的朋友魏华介绍给他.内容应包括、生活地方、父母情况、他的兴趣爱好、最擅长的科目、你们在一起常做些什么和他长大后准备干什么。

        根据以上要求,请你用60-70个词来完成这封短信。要求意思连贯、符合逻辑。信的开头和结尾已给出。

Dear Jack.

    I am glad to receive your letter and know you want to have some pen-friends in Chjna. Now let me tell you something about my friend,Wei Hua,a student of Class 3,Grrade 2 in Yucai Middle School                 

                                                                                                                                                                

                                                                                                                                                                

He would like to know something about your school life and your country.I'm sure  you  will become

good friends son.

                                                                                                                                                  Yours,

                                                                                                                                                   LiLei

单项选择题