Question

Which statement best describes the relationship between an object's density and its index of refraction?

A. As the mass per unit volume of the substance increases, the refraction index decreases.

B. As the optical density increases, the refraction index decreases.

C. As the physical density of the substance increases, the refraction index increases.

D. As the tendency of the atoms to absorb energy before reemitting it increases, the refraction index increases.

Answer 1

D.  This requires the light to travel more slowly which is a function of the refractive index.  

Answer 2

As the optical density increases, the refraction index decreases.

Step-by-step explanation:

Object's density is defined as the ratio of mass per unit volume i.e.

d = mass / volume

It shows the slowing down of the light wave when it moves from one medium to another. The optical density of air is low so its refractive index is 1.003 and for water the optical density is high and so the refractive index is 1.333. It is clear that there exists a direct relationship between the object's density and the refractive index.

Hence, the correct option is (b) " As the optical density increases, the refraction index decreases".