[填空题]
A laser beam is directed atqcftnl94j.: tbz ph1e bwrs7 eu09 j9, the Moon, 380,000 km from Earc39p x*xcudi *th. The beam diverges at an angd 9puix *c*3cxle $\theta$ (Fig. 8–37) of $1.4\times10^{-5}$ rad What diameter spot will it make on the Moon? m
Post time 2025-2-18 20:00:22
