$3$ An oil film $\backslash ((\backslash$mathrm$\{$n$\}=1\mathrm{.}45)\backslash )$ floating on water $\backslash ((\backslash$mathrm$\{$n$\}=1\mathrm{.}33)\backslash )$ is illuminated by white light at normal incidence. The film is $280$ nm thick. Find

a$)$ the wavelength and color of the light in the visible spectrum most strongly reflected

b$)$ the wavelength and color of the light in the visible spectrum most strongly transmitted

Answers:

a$)541$ nm $($green$)$

b$)406$ nm $($violet$)$