a light beam strikes a piece of glass with an incident angle of 45.00. the beam contains two colors: 600 nm and an unknown wavelength. the index of refraction for 600 nm light is 1.8. assume the glass is surrounded by air, which has an index of refraction of 1.000, what is the index refraction wavelength if its refraction angle is 7 degrees smaller than that of 600 nm light