AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.
Option A — Both A and R are true, and R is the correct explanation of A. Glass ($n$ = 1.52) has a higher refractive index than water ($n$ = 1.33), making it optically denser; so light travelling from water into glass bends towards the normal.
When light moves from a rarer medium (water, lower $n$) to a denser medium (glass, higher $n$), it slows down and bends towards the normal — this directly supports Assertion A. The Reason correctly states that glass is optically denser than water (1.52 > 1.33) and this is precisely why the bending towards the normal occurs, making R the correct explanation of A. Remember: optically denser = higher refractive index = light bends towards normal.