Question

Monochromatic light of wavelength 589 nm is incident from air on a
water surface. What are the wavelength, frequency and speed of
(a) reflected, and (b) refracted light? Refractive index of water is
1.33​

Answer 1

Wavelength of incident monochromatic light,

λ = 589 nm = 589 × 10−9 m

Speed of light in air, c = 3 × 108 m/s

Refractive index of water, μ = 1.33

(a) The ray will reflect back in the same medium as that of incident ray. Hence, the wavelength, speed, and frequency of the reflected ray will be the same as that of the incident ray.

Frequency of light is given by the relation,

v = c / λ

= 3 x 108 / 589 x 10-9

= 5 .09 x 1014 Hz

Hence, the speed, frequency, and wavelength of the reflected light are 3 × 108 m/s, 5.09 ×1014 Hz, and 589 nm respectively.