[填空题]
A laser beam is directed at tit hxh8qo(d,(9j:*ex 3t7 nm 9hq negkhe Moon, 380,000 km from Earth. Tfrkh123q gctcc1.ve )r43gc +loewc4he beam diverges at an a+ c 14lwo.13hrrg42 cteeqc 3kgcvcf)ngle $\theta$ (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
