Question

Question 11
The bluish colour of water in deep sea is due to

(a) the presence of algae and other plants found in water
(b) reflection of sky in water
(c) scattering of light
(d) absorption of light by the sea

Answer 1

Option (c) is correct.
The ocean (or sea) appears to be blue because water (like air) prefers to absorb longer wavelengths - which are red and orange, and scatter shorter- which is blue. As you go further deep in the ocean, less sunlight will reach the water, less scattering occurs, making the furthest depths of the ocean appear black without artificial light.