[填空题]
A laser beam is directede.,p a*yha.v w at the Moon07h c -zsglnjb8 r nfdk25fjc8+5huc+ , 380,000 km from Earth. The beam diverges at an angl -+5hcfjurc l+ 57gd0nnzbj hf28ks 8ce $\theta$ (Fig. 8–37) of $1.4\times10^{-5}$ rad What diameter spot will it make on the Moon? m