Section A: Choose the correct answer from the options given below.
Assertion (A): When a ray of light moves into a denser medium from a rarer one, it slows down and shifts away from the normal. On moving into a rarer medium from a denser one, it speeds up and turns towards the normal.
Reason (R): The refractive index of a rarer medium is lower because light travels faster in it than in a denser medium.
Reason (R): The refractive index of a rarer medium is lower because light travels faster in it than in a denser medium.