题目

 -- Oh, it's so disappointing that our team failed to win the final match! -- Well, don't worry. _____. A. Take things easy B. Take your time C. It isn't the end of the world.  D. That’s all right 答案：C20.人眼对绿光最为敏感。正常人的眼睛接收到波长为530 nm的绿光时，只要每秒有6个绿光的光子射入瞳孔，眼睛就能察觉。普朗克常量为6.63×10－34 J·s，光速为3.0×108 m/s，则人眼能察觉到绿光时所接收到的最小功率是……………………………………………………………（　　）A.2.3×10－18 W                                     B.3.8×10－19 WC.7.0×10－48 W                                     D.1.2×10－48 W