1. The problem statement, all variables and given/known data A thin film of oil (n = 1.23) is located on a smooth, wet pavement. When viewed perpendicular to the pavement, the film reflects most strongly red light at 640 nm and reflects no light at 569 nm. How thick is the oil film? 2. Relevant equations 2nt=(m+.5)*(wavelength)------constructive interference 2nt=m* wavelength------------destructive interference n=index of refraction t= thickness m= order number 3. The attempt at a solution So I tried to set the two equations together and using the corresponding wavelengths to solve for m. Next I just plugged m into one of the equations and using the corresponding wavelength to find t. Is that the correct method of doing this problem?