Question

Choose the correct option

The absolute refractive index ____

a) is expressed in dioptre
b) is expressed in m/s
c) of air is 3 × 108 m/s
d) has no unit​

Answer 1

Answer:

d) has no unit

Step-by-step explanation:

the refractive index of a material is a dimensionless number that describes how fast light travels through the material. It is defined as

$n \: = \: \frac{c}{v}$

where c is the speed of light in vacuum and v is the phase velocity of light in the medium.