Question

On entering in an optically rarer medium from an optically denser medium
(A) Speed of light increases
(B) Frequency remains unchange
(C) Wavelength increases
(D) Frequency decreases The correct options are
(A) and (B)
(A), (C) and (D)
(A), (B) and (C)
(A) and (D)​

Answer 1

(A), (B) and (C) is the correct answer.

1. When the light travels from optically denser medium to optically rarer medium, the speed of light changes. It decreases. The light ray also deviates away from the normal when travelling from denser to rarer medium.
2. It deviates towards the normal when moves from rarer to denser medium.
3. In the former condition, wavelength and speed of light decreases, while frequency remains unchanged.

Answer 2

Given:

Light enters an optically rarer medium from an optically denser medium.

To find:

Correct statements?

Calculation:

• Optically rarer medium is a one which has a higher velocity of light. And Optically denser medium is a one which has a lower the velocity of light.

So, whenever a light enters an optically rarer medium from an optically denser medium its velocity increases (Statement A).

• Now, as per Snell's Law, we can say that when the light is going from higher refractive index (denser) to lower refractive index (rarer), the light deviates away from the normal.

• This deviation occurs as a result of increased wavelength (Statement C).

Again, since the source of the electromagnetic wave is not changing during refraction, the frequency remains unchanged (Statement B).

So, statements A) , B), C), are all correct.

$\star$ Hope It Helps.