Monochromatic light of wavelength 589nm is incident from air on a water surface. Given, refractive index of water is 1.33.
Which of the following statement(s) is/are correct?
I. Frequency of reflected light and refracted light are same.
II. Wavelength of reflected light is more than that of refracted light.
III. Speed of reflected light is equal to that of refracted light.
IV. Intensity of reflected light is always more than that of refracted light.

Options

A. I and III
B. II and IV
C. I and II
D. III and IV

Answer

C

Explanation

Frequency does not change in reflection.
According to Snell's law of refraction, we get
`eta_(w)=(v_("air"))/(v_("water"))=(lamda_("air"))/(lamda_("water"))`
`rArr` As wavelength i.e. `lamda_("water")=(lamda_("air"))/(eta_(w))`
`(lamda_(air))/(4//3)=3/4lamda_(air)`
So, wavelength of reflected light is more than that of refracted light.