試題詳解

11. We wish to coat flat glass (n=1.5) with a transparent material (n=1.25) so that reflection of light at wavelength 600 nm is eliminated by interference. What minimum thickness can the coating have to do this?
(A) 30 nm
(B) 100 nm
(C) 120 nm
(D) 400 nm
(E) 480 nm