Question

A fish looking up through the water sees the outside world contained in a circular horizon. If the refractive index of water is 4/3 and the fish is 12cm below the surface, the radius of this circle in cm is

(a) 36√5 

(b) 4√5

(c) 36√7 

(d) 36/√7

Answer 1

(d) : For total internal reflection,