Question

ASSERTION AND REASON:
(a) Assertion and Reason are correct and Reason is the correct explanation of Assertion.
(b) Both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion.
(c) Assertion is correct but Reason is incorrect.
(d) Assertion is incorrect but Reason is correct.


Assertion(A): A ray of light travelling from a rarer medium to a denser medium slows down and bends away from the normal. When it travels from
a denser medium to a rarer medium, it speeds up and bends towards the
normal.
Reason (R): The speed of light is higher in a rarer medium than in a denser
medium.

Answer 1

Assertion(A): A ray of light travelling from a rarer medium to a denser medium slows down and bends away from the normal. When it travels from a denser medium to a rarer medium, it speeds up and bends towards the normal.

Reason (R): The speed of light is higher in a rarer medium than in a denser medium.

Assertion is incorrect but Reason is correct ✔️

But why??

• Whenever light passes from an optically rarer medium to an optically denser medium after refraction the light ray bends towards the normal. This is because in the optically denser medium the velocity of light decreases . $\boxed{v=\dfrac{c}{\mu}}$, here $\mu$ is refractive index.

• Similarly, when light passes from an optically denser medium to an optically rarer medium it bends away from the normal because after refraction the velocity of light increases.

• Please see the diagrams for reference !

Hope It Helps.

Answer 2

Assertion and reason on refraction of light

Explanation:

• When a ray of light travels from rarer medium to denser medium then light bends toward the normal because speed of light slows down in the denser medium due to which light bends toward the normal.
• In above case angle of incidence is greater than angle of refraction.
• When a ray of light travels from denser to rarer medium then light bends away from the normal because speed of light travels fast in rarer medium due to which it bends away from normal.
• In this case angle of refraction is greater than angle of incidence.
• So, assertion is incorrect but reason is correct.

Therefore, Option(d) is correct.