The reason for a swimming pool to appear less deep than the actual depth is -

A lemon kept in water in a glass tumbler appears to be larger than its actual size. It is because of

Soap solution used for cleaning purpose appears cloudy. This is due to the fact that soap micelles can

The twinkling of a star is due to :

The minimum distance of clear vision for a normal healthy eye of human being is supposed to be :

The sun is visible to us a few minutes before the actual sunrise because of :