Question

The blue colour of the water in the sea is due to
A) refraction of the blue light by the impurities in seawater
B) refraction of the blue sky by water molecules
C) scattering of blue light by water molecules
D) absorption of other colours except the blue colour by water molecules
E) blue colouring of the sea water

Answer 1

Hint: To solve this question first we must know the types of scattering of light.

Complete step by step solution:
The actual colour of sea water is not blue, but it appears to be blue. The ocean is blue because water absorbs colours in the red part of the light spectrum. Like a filter, this leaves behind colours in the blue part of the light spectrum for us to see. The ocean may also take on green, red, or other hues as light bounces off floating sediments and particles in the water. Blue colour of water in the sea is due to scattering of light by water molecules. As blue has smaller wavelength, therefore scattering of blue is exceptionally large.

We know, scattering probability is directly proportional to 14 , where λ is the wavelength. The water of the sea is not blue but because of Rayleigh scattering, Particles and dissolved substances, depending on their size and physical properties (including the type of molecular bonds), will scatter or absorb visible light at different wavelengths and actually change the colour of the water. Therefore, the blue colour of the water of the sea is due to scattering of blue light by solid particles.

Rayleigh scattering is wavelength dependent with shorter wavelengths being more scattered.

Thus, option B is correct. ​

Note: Rayleigh scattering from molecules in the atmosphere which gives rise to the blue sky we see on a fine day. The blue light from the sun striking the upper atmosphere is scattered approximately 10 times more than red light, so overhead the blue light is scattered into the eye of an observer while the red light goes largely unscattered and back out into space.