Question

With the help of suitable diagram, explain the phenomenon of early sunrise and delayed sunset.

Answer 1

The sun seems to rise two minutes before the actual sunrise and two minutes after the actual sunset due to the phenomenon of atmospheric refraction.

During sunrise and sunset, when the sun is just below the horizon, the light from the sun, while coming towards the earth, suffers refraction from a rarer to a denser layer and so it bends towards the normal at each refraction. Due to the continuous bending of light at different successive layers, the sun can be seen even when its actual position is just below the horizon.