Question

Determine the change in wavelenght of light during its passage from air to glass, if the refracrtive index of glass with respect to air is 1.5 and the frequency of light is 5 x 10¹⁴ Hz. Find the wave number of light in glass (velocity of light in air c = 3 X 10⁸ m/s)

Answer 1

Given: `amu_g` = 1.5, v = 5 x 10¹⁴ Hz

To find: a. Change in wavelength (Δλ)

b. Wave number of light in glass (`barν_e`)

Change in wavelength Δλ = λ_a - λ_g

= 6000 – 4000

= 2000 Å

Change in wavelength is 2000 Å

Wave number of light in glass = `barv_ g = 1/lambda_g`

= `1/(4000Å)`

= `2.5 xx 10^6 m^(-1)`

Wave number of light in glass is 2.5 x 10⁶ m^–1