Question

What is atmospheric refraction? Use this phenomenon to explain advance sunrise and delayed sunset with the help of diagram.

Answer 1

Atmospheric refraction is the refraction of light caused by the earth's atmosphere due to change in the refractive indices of different layers.
Advanced sunrise:

• When the sun is slightly below the horizon, light rays coming from the sun travel from the rarer to denser layer of air.
• Because of atmospheric refraction of light, light appears to come from a higher position above the horizon.
• Thus, the sun appears earlier than the actual sunrise.

Delayed sunset: Same reason, because similar refraction occurs at the sunset.