Question

The index of refraction of fused quartz is 1⋅472 for light of wavelength 400 nm and is 1⋅452 for light of wavelength 760 nm. Find the speeds of light of these wavelengths in fused quartz.

Answer 1

Given :

Fused quartz refractive index= 1.472 for wavelength =400nm

Fused quartz refractive index= 1.452 for wavelength =760nm

We know

μ=C/V

let speed of light for wavelength 400nm be V400

V400= C/μ

=3x10⁸/1.472

=2.04x10⁸ m/s

let speed of light for wavelength 760nm be V760

V760= C/μ

=3x10⁸/1.452

=2.07x10⁸ m/s

Answer 2

We know that, μ2/μ1 =V1/V2