[填空题]
A laser beam is dire+rky vudy-q ode,t6 ;9cted at the Moonv9b yufxy-: w,+0 e0h8d 3k xjegzlw,f, 380,000 km from Earth. The beam diverges at an a83y :z y9l+0f,e-dbu0kefg jxhw, xv wngle $\theta$ (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
