# Problem: White light is incident normally on a thin soap film (n = 1.33) suspended in air.What are the two minimum thicknesses that will constructively reflect yellow (λ = 590 nm) light?

###### FREE Expert Solution

The equation for a constructive interference is:

$\overline{){\mathbf{2}}{\mathbit{\eta }}{\mathbf{t}}{\mathbf{=}}{\mathbf{\left(}}{\mathbf{m}}{\mathbf{+}}\frac{\mathbf{1}}{\mathbf{2}}{\mathbf{\right)}}{\mathbf{\lambda }}}$, where t is the thickness of the film and η is the refractive index of the film.

###### Problem Details

White light is incident normally on a thin soap film (n = 1.33) suspended in air.

What are the two minimum thicknesses that will constructively reflect yellow (λ = 590 nm) light?