题目

Happiness doesn’t mean being joyful or laughing all day long. Although happiness should be defined by each of us for ourselves, a general understanding of it could be having more good moments and memories than bad ones and having an overall feelings of satisfaction and fulfillment. 【1】 Read on and you will know the answer.*【2】Many of us have the impression that we’re not allowed to be happy and that we don’t deserve it. Well, we all deserve to be happy, no matter what others say or even what we believe. So allow yourself to be happy.*Smile even if you don’t feel like it. Yes, s.“利用双缝干涉测定光的波长”实验中，双缝间距d=0.4mm，双缝到光屏的距离L=0.8m，用某种单色光照射双缝得到干涉条纹如图所示，分划板在图中A、B位置时游标卡尺读数也如图所示，则：（1）分划板在图中A、B位置时游标卡尺读数xA=11.1mm，xB=_____mm（2）该单色光的波长λ=______m；（结果保留三位有效数字）（3）若改用频率较高的单色光照射，得到的干涉条纹间距将______（填“变大”、“不变”或“变小”）