Question

Optical density of a medium depends on :

• A. density of the medium
• B. thickness of the medium
• C. velocity of light in that medium
• D. none of these

Answer 1

The correct option is C velocity of light in that medium

Answer is C.

The speed of light depends on the characteristics of the medium on which it is incident; the optical density of the medium influences the speed of light to a great extent.
Optical density of the medium refers to the sluggish tendency of the atoms of a material to retain the energy absorbed from the electromagnetic wave in the form of vibrating electrons before being re-emitted as an electromagnetic disturbance. The speed of electromagnetic waves in a material with higher the optical density will be slow.
Hence, Optical density of a medium depends on Velocity of light in that medium.