Question

A light wave has a 670 {\rm nm} wavelength in air. Its wavelength in a transparent solid is420 {\rm nm} .a)What is the speed of light in this solid?b)What is the light's frequency in the solid?

Answer 1

Answer:

Explanation:

given,

Light wave wavelength in Air, λ_(vac) = 670 nm

wavelength in transparent solid, λ= 420 nm

Refractive index of the solid

$n = \dfrac{\lambda_{vac}}{\lambda}$

$n = \dfrac{670}{420}$

   n = 1.6

a) speed of light in the solid

$v = \dfrac{c}{n}$

$v = \dfrac{c}{1.6}$

       v = 0.625 c

b) light's frequency in the solid

  $f = \dfrac{c}{\lambda_{vac}}$

frequency of light remain same when light move from one medium to another.

 f is the frequency of light

  $f = \dfrac{3\times 10^8}{670\times 10^{-9}}$

        f = 4.47 x 10⁻¹⁴ Hz

the light's frequency in the solid is equal to 4.47 x 10⁻¹⁴ Hz