Question

A red light of wavelength 6400A° in air has wavelength 4000A° in glass. If the wavelength of violet light in air is 4400A°, find its wavelength in glass.

(Assume that μ_r ≈ μ_v)

Answer 1

Given:

(λ_r)_air = 6400A°

(λ_r)_glass = 4000A°

(λ_v)_air = 4400A°

To find:

(λ_v)_glass =?

Formula:

(λ_r)_air/(λ_r)_glass = (λ_v)_air/(λ_v)_glass

∴ (λ_v)_glass = (λ_v)_air × (λ_r)_glass / (λ_r)_air

_∴ (λ_v)glass = 4400 × 4000 / 6400

_∴ (λ_v)glass =2750A°