[填空题]
Spy planes fly at extr5aj26o:gk d/ystfqv 57eztxkr v 4 7(pvora.1 emely high altitudes (i akerix);*mls+x z(8 25 $km$) to avoid interception. Their cameras are reportedly able to discern features as small as 5 $cm$. What must be the minimum aperture of the camera lens to afford this resolution? (Use $\lambda=550\mathrm{~nm}.$)D = cm
