[填空题]
A laser beam is directed at the Moon, 380,000 km from ko6 dnw l3l1w3v0-vzbEar 9:boa 3nuay*xogdy5 -th. The beam diverges at an a-9 go u aon*d3yy:5xabngle $\theta$ (Fig. 8–37) of $1.4\times10^{-5}$ rad What diameter spot will it make on the Moon? m