Explain the following :
A coin placed at the bottom of a vessel appears to be raised when water is poured in the vessel.
The coin at a appears to be at B i. e. depth of coin observed is less than the actual depth at A.
The ray of light starting from A (denser) medium bends away from the normal. Due to the Refraction of light, the coin appears at B at a lower depth. Hence, in the same way, the depth of water appears to be less deep.