[填空题]
A laser beam is directed at the Moon, 380,000 km from Earthk1 :xdb, qjl7+z+lcxxxvof7u4o5a6 :2, mf li6fm vrn. The beam diverges at m:n fvlx6 r,u4o 7f6iva52mfo an angle $\theta$ (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
