Question

The refractive index \[n\] of a medium is related to the speed of light by:

Options

• \[n = c \cdot v\]

• \[n = \frac{v}{c}\]

• \[n = \frac{c}{v}\]

• \[n = \frac{c^2}{v}\]

Answer 1

The refractive index is defined as \[n = \frac{c}{v}\], the ratio of the speed of light in vacuum to its speed \[v\] in the medium. Since light slows down in a material medium (\[v < c\]), every material medium has \[n > 1\].