题目

Dick lived in England. One day in January he said to his wife， I'm going to fly to New York next week because I've got some work there. Where are you going to stay there？”his wife asked. I don't know yet. Dick answered. Please send me your address from there in a telegram （电报）， his wife said. All right， Dick answered. He flew to New York on January 31st and found a nice hotel in the center of the  city.  He  put  his  things  in his room and then he sent his wife a telegram. He put the address of his hotel in it. In the evening he didn't have any work， so he �现有毛玻璃屏A、双缝B、白光光源C、单缝D和透红光的滤光片E等光学元件，要把它们放在图所示的光具座上组装成双缝干涉装置，用来测量红光的波长。 （1）将白光光源C放在光具座最左端，依次放置其他光学元件，由左至右，表示各光学元件的字母排列顺序应为C、  、    、     、A。 （2）本实验的步骤有： ①取下遮光筒左侧的元件，调节光源高度，使光束能直接沿遮光筒轴线把屏照亮； ②按合理顺序在光具座上放置各光学元件，并使各元件的中心位于遮光筒的轴线上； ③用米尺测量双缝到屏的距离； ④用测量头(其读数方法同螺旋测微器)测量数条亮纹间的距离。 在操作步骤②时还应注意         和       。 （3）将测量头的分划板中心刻线与某亮纹中心对齐，将该亮纹定为第1条亮纹，此时手轮上的示数如图甲所示。然后同方向转动测量头，使分划板中心刻线与第6条亮纹中心对齐，记下此时图乙中手轮上的示数    mm，求得相邻亮纹的间距Δx为   ?mm。 （4）已知双缝间距d为2.0×10-4m，测得双缝到屏的距离l为0.700m,由计算式λ=      ，求得所测红光波长为         nm。