Question

a path length t in a glass plate of refractive index n is equivalent to....path length in vacuum.​

Answer 1

Path length in vacuum will be - nt.

Optical path length is defined as the path covered by light in any optical medium.

It is calculated as the product of path length and refractive index of the medium represented by n.

Given in question is the value of path length as t and refractive index as n.

Hence, optical path length will be nt. n is calculated as speed of light in vacuum to the speed of light in any medium.

Answer 2

A path length t in a glass plate of refractive index n is equivalent to nt path length in vacuum.​

Explanation:

• A path length is defined as the distance traveled by an object.
• The path length of the glass is defined as the distance traveled by the light in the glass.
• The path length in vacuum is the product of path length of the light in glass and refractive index of the medium.
• Optical path length = n × t = nt