题目

如图是质谱仪的工作原理示意图，带电粒子被加速电场加速后，进入速度选择器内相互正交的匀强磁场和匀强电场的强度分别为B何E，平板S上有可让粒子通过的狭缝P和记录粒子位置的胶片A1A2 ． 平板S下方有磁感应强度为B0的匀强磁场．下列说法正确的是（） A . 质谱仪是分析同位素的重要工具 B . 速度选择器中的磁场方向垂直纸面向里 C . 速度选择器只能一种电性，且速度等于 的粒子 D . 打在A1处的粒子比打在A2处的粒子的比荷小 基础训练篇（20） Once upon a time there was a rich merchant 1 __      _____ had four wives. He loved the 4th wife the most.  He took great care of her and gave her nothing 2__________ the best. He also loved the 3rd wife very much. He was very         3         __ (pride) of her and always wanted to show off her to his friends. He also loved his 2nd wife. She is __4 ___________very considerate person, always patient and in fact is the merchant’s close friend. __5___________ the merchant faced some problems, he always turned to his 2nd  wife and __6____________ would always help him out and tide(帮助渡过) him 7__________ difficult times. Now, the merchant’s 1st wife is a very loyal partner and has made great 8___________ (contribute) in maintaining his wealth and business as well as 9____________ (take) care of the household. _10   ________, the merchant did not love the first wife and although she loved him deeply, he hardly took notice of her.