[填空题]
A laser beam is directed at the Moon, 380,000 km from Earth.i 55lvxgnsv y/n3ha80 The bvj*k02zz(b e qezi/z+ eam diverges at a qj e0ekz2zvbz*( i+/zn angle $\theta$ (Fig. 8–37) of $1.4\times10^{-5}$ rad What diameter spot will it make on the Moon? m