What wavelength monochromatic source in the visible region $(390$ to $710\mathrm{nm)}$ can be used to constructively reflect off a soap film $(n=1\mathrm{.}46)$ if the film is $240$nm thick?

 

  

 

  

Answer rating: 100% (QA)

The reflection of light from the soap film leading to constructive interference is governed by the p... View the full answer