JAMB Physics 1980 Question 35

In the above diagram, a ray of light passes from glass into air. If the angle of incidence in glass is α and the angle of refraction in air is β, which of the following statements is true?

1. A.α = β
2. B.The refractive index of glass is sin θ/sin α
3. C.The ray suffers total internal reflection if β is greater than the critical angle
4. D.The ray will suffer total internal reflection if α is less than the critical angle
5. E.The refractive index of glass is sin α/sin β