1. When light rays enter the eye, most of the refraction occurs at the (a) crystalline lens (b) outer surface of the cornea (c) iris pupil

Answer is (b) outer surface of the cornea

Explanation:

Cornea is a thin membrane through which light is entered. The incident light rays are bent due to cornea and are converged which results in image formation at retina. So, most of the refraction occurs at the iris of the eye.