[填空题]
A laser beam is direy5f,msgx *ua7t lbtdpk1,9m fh xk */1 +qw0ac27:qo g0xaflro*vg b+cted at the Moon, 380,000 km from Earth. The beam diverges at an angle o *ga0ao7wrqbq vl:02gxf ++c$\theta$ (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
