[填空题]
A laser beam is directed at the l 9l2vl6td)vg m kmz184xnm42zuw kh2 Moon, 380,000 km from Earth. The beam dive32jonwt7 gtmmw5 jf: uwg1-f2rges at an aong37t-wjf juw w2 tmf1:mg52ngle $\theta$ (Fig. 8–37) of $1.4\times10^{-5}$ rad What diameter spot will it make on the Moon? m