Question

What happens to the speed of light as light from the sun enters the earth's atmosphere and shines down into the oceans, and why?
A. The light speeds up as it enters the atmosphere, and slows as it enters the water because water is a denser medium than air so it absorbs more of the light's energy.
B. The light slows down as it enters the atmosphere because the air absorbs some light energy; the light speeds up in the water because light moves faster through liquids.
C. The light speeds up as it enters the atmosphere and then speeds again as it enters the water because light is able to absorb energy from each medium through which it travels.
D. The light slows down as it enters the atmosphere, and then slows again as it enters the water because some of its energy is absorbed by the different media through which it passes.

Answer 1

The correct answer would be letter A. The light that comes from the sun would eventually speed up as it enters the earth's atmosphere, wherein the air is less dense. However, as it reaches the ocean, the speed of the air would then decrease since the ocean is a lot denser compared to air. The phenomenon is called "refraction."

Answer 2

The correct answer is (D)

In this question we need to compare three medium because the sunlight from space (vacuum) enters into the earth's atmosphere (denser) and then passes to water (denser) medium. The speed of light is maximum in vacuum and the speed of light slows down as it enters the earth's atmosphere because some of the energy is absorbed by the particles present in air. Then this light from air enters to water which is denser medium and the energy is absorbed by the different media by which light passes.

The phenomenon of bending of light when it enters from a rarer medium to denser medium is called refraction.