A ray of light of wavelength 680 nm is travelling in a medium X where the refractive index is 1.20 and enters a medium Y of refractive index 1.80. The ray makes an angle of 35∘ with the normal at the boundary. Calculate:
a. the angle of refraction
b. the wavelength of the light in Y.
c. A ray moving in Y enters X making an angle of 32∘ with the normal. What is the angle of refraction?
d. What is the critical angle for a ray moving from Y to X?