[填空题]
A lens appears greenisty. 999 wrapvnlrpdv k0.o b/1qp p.9sh g5: rhgfr9nugj0h5 dc 4/t()pz(ofc vyellow ($\lambda\;=\;570\;mm$ is strongest) when white light reflects from it. What minimum thickness of coating $(n=1.25)$ do you think is used on such a glass $(n=1.52)$ lens, and why? $t_{min}$ nm
