[填空题]
A laser beam is directed at the Mo5 + bz+o:oqbuoon, 380,000 km from Eariftx znw :5qz9)ivm-mew+u1 -th. The beam diverges a )f-z+tni :ueww9 x-z vqm1m5it an angle $\theta$ (Fig. 8–37) of $1.4\times10^{-5}$ rad What diameter spot will it make on the Moon? m