Question

When you look through a 3.7 mm thick window comprised of a material whose refractive index is 1.59, by what time interval is the light you see delayed by having to go through glass instead of air?
By how many wavelengths is it delayed, if its vacuum wavelength is 600 nm?

Answer 1

I answered the first part. The second,
the wavelength passing in time of delay is speedlight*timedelay/600nm