Section C - Wave & Optics Handout June 1994, Paper III, Question #2 a) i) In terms of the wave theory, explain why refraction of light occurs. Illustrate your answer with a labelled diagram. ii) With the aid of ray diagrams, explain the terms 'refractive index' and 'critical angle'. (4 marks) DIAGRAMS: (4 marks) b) Normal Air 619 P Ice A ray of light hits a block of ice at P, as shown in the diagram above. The refractive index of ice is 1.6. i) Calculate the angle of refraction of the ray of light incident at P. (3 marks) ii) Calculate the value of the critical angle for ice. (3 marks) iii) Draw a large diagram to show the path of the ray of light through the ice. Mark the sizes of the angles of incidence and refraction and show clearly where the ray leaves the ice. (6 marks) Total = 20 marks