How does the sun appear at sunset?

 

Solution:

Concept: Refraction of light refers to the bending of a light ray as it travels from one medium to another.

Because the speeds of light in the two media differ, light refracts when it travels from one to the other.

A ray of light bends towards the normal as it travels from a rarer medium to a denser medium.

A ray of light bends away from the normal as it travels from a denser medium to a rarer medium.

Many fascinating phenomena are caused by light refraction through the atmosphere.

Because of refraction of light through the atmosphere, the Sun is visible a little before sunrise and until a little after sunset.

The air layers closer to the earth are denser than those above it.

When the sun is below the horizon at sunrise and sunset, light rays from the sun are incident on these layers.

They pass through successively denser layers, becoming increasingly bent towards the normal until they fall upon the observer's eye.

These rays appear to come from above the horizon to the observer. Because of this, we can see the sun before it rises above the horizon and also after it sets below the horizon. As a result, option 2 is correct. The time difference between an early rise and a late setting of the Sun is about 2 minutes.