Question

Which of the following statements correctly describes the index of refraction of a material? Select all that apply.

The index of refraction is the ratio of the speed of light in a material to the speed of light in a vacuum.
The index of refraction of a material must be greater than 1.
The index of refraction is the ratio of the speed of light in a vacuum to the speed of light in the material.
The index of refraction of a material must be less than 1.
The index of refraction of water is less than the index of refraction of air.​

Answer 1

The index of refraction is the ratio of the speed of light in a vacuum to that in the material, and it must be greater than 1 because light travels slower in any material than in a vacuum. Water has a higher index than air, indicating slower light speed in water.

Step-by-step explanation:

The index of refraction is a property of a material that describes how light propagates through it compared to the propagation through a vacuum. Two statements that correctly describe the index of refraction of a material are: The index of refraction is the ratio of the speed of light in a vacuum to the speed of light in the material, and the index of refraction of a material must be greater than 1.

This is because light always travels slower in a material than it does in a vacuum, which makes the index of refraction (n) to be calculated using the formula n = c/v, where c is the speed of light in vacuum and v is the speed of light in the material. As for the comparative index of refraction values, water (n=1.333) has a higher index of refraction than air (n=1.0003), which means light travels slower in water than in air. Therefore, the correct statements are that the index of refraction is the ratio of the speed of light in a vacuum to the speed of light in the material, and the index of refraction of a material must be greater than 1. The index of refraction of water being less than that of air is incorrect.

Answer 2

Option C and D only

Step-by-step explanation:

Option A is incorrect because refractive index of a material is the ratio of speed of light in vacuum to the speed of light in a any given medium

Option B is correct as the speed of light in vacuum is always greater than the speed of light in any given medium.

Option C is correct

Option D is incorrect

Option E is incorrect because the denser the medium the more is the refractive index. Water is denser than air, hence it should have more refractive index as compared to that of air.