[填空题]
A laser beam is direax5)9ujtidjf , o* m2ufj+j izgnb30.sq op(/cted at the Moon, 380,000 km from Earth. The ber shab,maq1k 9h- e8s0am diverges aeb0askms1 8 q-a r9h,ht 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
