The absolute index of refraction of medium y is twice as great as the absolute index of refraction of medium x. as a light ray travels from medium x into medium y, the speed of the light ray is

The speed of the light ray is halved

Explanation:

The index of refraction of a medium is the ratio between the speed of light in a vacuum (c) and the speed of light in the medium (v):

For medium X, we have

(1)

For medium Y, we have

(2)

Dividing (1) by (2), we find

(3)

In this problem, the index of refraction of medium Y is twice as great as the index of refraction of medium X:

Substituting this into eq.(3), we get

So, as a light ray travels from medium X into medium Y, the speed of the light ray is halved.

does anyone know or what?