A coin placed at the bottom of a tank appears to be raised when water is poured into it. Explain

1 answer

It happens due to the, phenomenon of refraction of light. When the rays of light from the coin, in the denser medium, fall on the interface separating the two media, the rays of light move away from the normal after refraction. The point from which the refracted rays appear to come gives the apparent position of the coin. As the rays appear to come from a point above the coin, therefore, the coin seems io be raised.