Light with a wavelength of 600 nm is incident on a gemstone made of cubic zirconia (ᡦ = 2.18) from air. The light makes an angle of 30° with the surface of the gem before entering it. The refracted ray makes an angle of 30° with the normal. What is the frequency of the light in the gemstone? (1 THz = 1 terahertz = 10ଵଶ Hz)

500 THz.

Explanation:

Velocity of light in air = 3 x10⁸ m / s

wave length of light = 600 nm

= 600 x 10⁻⁹ m

= 6 x 10⁻⁷ m

frequency in air = velocity in air / wave length in air

= 3 x 10⁸ / 6 x 10⁻⁷

=.5 x 10¹⁵ Hz

= 5 x 10¹⁴Hz

= 500 x 10¹² Hz

= 500 THz

When light enters the medium of gem, its wavelength and velocity changes in such a way that its frequency remains constant. So in the medium of gem also its frequency remains 500 THz.