Question

When light propagates through two adjacent materials that have different optical properties, some interesting phenomena occur at the interface separating the two materials. For example, consider a ray of light that travels from air into the water of a lake. As the ray strikes the air-water interface (the surface of the lake), it is partly reflected back into the air and partly refracted or transmitted into the water. This explains why on the surface of a lake sometimes you see the reflection of the surrounding landscape and other times the underwater vegetation. These effects on light propagation occur because light travels at different speeds depending on the medium. The index of refraction of a material, denoted by n, gives an indication of the speed of light in the material. It is defined as the ratio of the speed of light c in vacuum to the speed v in the material, or n=cv

When light propagates from a material with a given index of refraction into a material with a smaller index of refraction, the speed of the light
What is the minimum value that the index of refraction can have?
a. 0
b. +1
c. −1
d. between 0 and 1

Answer 1

b. +1

Step-by-step explanation:

Given,

Speed of light in vacuum = c

Speed of light in any medium = v

Refractive index = n

To find: minimum value of refractive index.

We know that,

`n = (c)/(v)`

We know that speed of light in vacuum is fixed and there is nothing in this universe faster than that so value of c is fixed.

Now, speed of light in any medium can not be greater than the speed of light in vacuum. It means,

c ≥ v

So that means the maximum speed of light in any medium can only be equal to c. Thus minimum value of refractive index is,

`n = (c)/(c)`

n = +1