A lens appears greenish yellow ($\lambda$ = 570 nm 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 lens (n = 1.52), and why?
Source: Giancoli, Douglas C., Physics: Principles with Applications, 7th Edition, 2014.
230 nm. With yellow-green reflected, more red and blue will be transmitted.