[填空题]
A laser beam is directed at the Moon, 3wqzw r tg +-4;u3ghnm.80,000 km from Earthjikk lxtq+5+v zl73f) . The beam diverges at an ang7l x5+vjzfq ikt k3l+)le $\theta$ (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
