Question

Monochromatic light of wavelength $589nm$ 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 $\mathrm{1.33.}$

Answer 1

(a) Reflected light: (wavelength, frequency, speed same as incident light)

Since, $\lambda =589nm,c=3.00\times {10}^{8}m{s}^{-1}$

Now, $\nu =\frac{c}{\lambda }=\frac{3\times {10}^8}{589\times {10}^{-9}}$ = $5.09\times {10}^{14}{s}^{-1}$

(b) Refracted light: (frequency same as the incident frequency)

$\nu =5.09\times {10}^{14}Hz$

$v=\frac{c}{n}=2.26\times {10}^{8}m{s}^{-1}$

$\lambda =\frac{v}{c}=\frac{v}{nv}=444nm$