(a) Define absolute refractive index. 

(b) The path of a light ray from three different media A, B and C for a given angle of incidence is shown below. Study the diagrams and answer the following questions:

(i) Which of the three media A, B or C has maximum optical density? (ii) Through which of the three media, will the speed of light be maximum? (iii) Will the light travelling from A to B bend towards or away from the normal? (iv) Will the refractive index of B relative to C be more than unity or less than unity?