[填空题]
A laser beam is dire 8-* wzwmgpl9r *ds6kj hc u 0hrk,i9wdr5o+1hrde56af 8e6ht cted at the Moon, 380,000 km from Earth. The beam diverges at an h6dd *hs 9i ru1dw6 at r+58hho06 5rkfe,kejcangle $\theta$ (Fig. 8–37) of $1.4\times10^{-5}$ rad What diameter spot will it make on the Moon? m
Post time 2025-2-18 20:00:22
