You Apply a Material with N = 1

Multiple Choice

You apply a material with n = 1.25 to a lens (n_g = 1.5) to make a nonreflective coating due to destructive interference at a wavelength (in a vacuum) of 555 nm.What is the minimum thickness of the coating that you need?

A) 56 nm
B) 110 nm
C) 220 nm
D) 280 nm
E) 140 nm