Need urgent help with light reflection problems Here are my problems: 1) A beam of light has a wavelength of 610 nm in vacuum. a: What is the speed of this light in a liquid whose index of refraction at this wavelength is 1.45? I used n=c/v to get 2.07x10^8 m/s. This is correct. b: What is the wavelength of these waves in the liquid? I suppose I would use v=lambda*f v=2.07x10^8 (from part a), but what is f?? 2) A ray of light is incident in air on a block of a transparent solid whose index of refraction is n. If n=1.3, what is the largest angle of incidence a for which total internal reflection will occur at the vertical face? I used sin (crictical angle) = nb/na, where nb=1 and na=1.3. The critical angle is the smallest angle for which total internal reflection occurs. How do I obtain the largest?? Any help would be greatly appreciated!!