[填空题]
A laser beam is directed at th; afpdl)4i3utmz rn al20,f k9e Moon, 380,000 km from yxd, xxx2ea+ 3(js82zrr p (oyEarth. The beam diverges at anp(2syrx2e dyxa8 rj(,xz+ x 3o 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
