Question

Assertion :When a ray of light enters glass from air,its frequency decreases. Reason: The velocity of light in glass is same as that in air.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is D Both Assertion and Reason are incorrect

We have $c=\nu \lambda$
On entering any medium , the frequency remains constant.
The speed of light, like that of all waves, is dependent on the medium through which it is travelling. When light moves from one medium into another (for example, from air to glass), the speed of light changes because refractive index of medium changes.Hence, assertion and reason both are incorrect.