# A parallel beam of white light is incident normally

Question:

A parallel beam of white light is incident normally on a water film $1.0 \times 10^{-4} \mathrm{~cm}$ thick. Find the wavelength in the visible range ( $400 \mathrm{~nm}-750 \mathrm{~nm}$ ) which are strongly transmitted by the film. Refractive index of water $=1.33$.

Solution: