[填空题]
A laser beam is directts3w6ch 6hy l(a3 c.tqed at the Moon, 380,06 c8i. xp(pq rkj(p(ot00 km from Earth. The beam diverges at an p(r( kcijq (.potx8p 6angle $\theta$ (Fig. 8–37) of $1.4\times10^{-5}$ rad What diameter spot will it make on the Moon? m