JAMB Physics 1983 Question 16

Which of the following conditions are necessary and sufficient for total internal reflection to take place at the boundary between two optical media? I. Light is passing from optically denser medium to optically less dense medium II. Light is passing from optically less dense medium to optically denser medium III. Angle of incidence is greater IV. Angle of incidence is lesser

1. A.I and II only
2. B.II and III only
3. C.III and IV only
4. D.I and III only
5. E.II and IV only.