The refractive index of a material is a measure of how much light slows down when it enters that material from a different medium. It is defined as the ratio of the speed of light in vacuum to the speed of light in the material. In this case, we are given that the refractive index of glass for light going from air to glass is 3/2.

Refractive Index Definition
The refractive index (n) of a material is defined as the ratio of the speed of light in vacuum (c) to the speed of light in the material (v).

n = c/v

Light going from air to glass
When light travels from air to glass, it slows down due to the change in the medium. The refractive index of glass for light going from air to glass is given as 3/2. This means that the speed of light in glass is two-thirds of the speed of light in vacuum.

Light going from glass to air
To find the refractive index for light going from glass to air, we can use the reciprocal of the refractive index for light going from air to glass.

The refractive index for light going from glass to air (n') can be calculated as:

n' = 1/n

Substituting the given value of n = 3/2, we have:

n' = 1/(3/2) = 2/3

Therefore, the refractive index for light going from glass to air is 2/3.

Explanation
The refractive index of a material depends on the speed of light in that material compared to the speed of light in vacuum. When light travels from air to glass, it slows down and the refractive index is greater than 1. When light travels from glass to air, it speeds up and the refractive index is less than 1. The refractive index for light going from glass to air is the reciprocal of the refractive index for light going from air to glass.

4/6