Question

A beam of light crept from air to water. If the refractive index for water is 1.5; air refractive index is 1 and the speed of light propagation in the air is 3 × 10 ^ 8 so determine the speed of light propagation in water?

Answer 1

Known :

na = 1.5

nu = 1

vu = 3x10⁸ m / s

Asked: Va?

Answered:

Va / Vu = nu / na

Va / 3x10⁸ = 1 / 1.5

Va = 1 / 1.5 x 3x10⁸

Va = 2x10⁸ m / s

Answer 2

Known :

na = 1.5

nu = 1

vu = 3x10⁸ m / s

Asked: Va?

Answered:

Va / Vu = nu / na

Va / 3x10⁸ = 1 / 1.5

Va = 1 / 1.5 x 3x10⁸

Va = 2x10⁸ m / s