Which statement is true of light when it speeds up on entering another medium?

A. The index of refraction is higher in the second medium than it was in the first.

B. The index of refraction is lower in the second medium than it was in the first.

C. The speed of light through the medium is close to the speed of light in a vacuum.

D. The angle of incidence equals the angle of refraction in this instance.

B. The index of refraction is lower in the second medium than it was in the first.

Explanation:

Light is the fastest thing in the universe but even the speed of light varies. It depends on the medium it is passing through. Refractive index is a measure to show the density of a medium. The refractive index of a medium and speed of light are inversely proportional to each other. It means that as the refractive index increases the speed of light will decrease and vice versa.

Here, the speed of light is increasing while entering the second medium which means the refractive index of second medium is lower than that of first one.

Only B is correct.

The index of refraction is lower in the second medium than it was in the first ✓

According to the question : Which statement is true of light when it speeds up on entering another medium?

If the refractive index was greater than the 1st medium (like in answer A) light speed reduces.

But if the refractive index was lower, speed of light increases.