[填空题]
A laser beam is direu skj3othxn. ,3e89cj0 2 ymywcted at the Moon, 380,000 km f )ak5nlzn +d.olxj:k2 rom Earth. The beam diverges at an azandk. lo5kl+j) x :n2ngle $\theta$ (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
