Question

Explain why, the sun can be seen about two minutes before actual sunrise. Draw a diagram to illustrate your answer.

Answer 1

To explain:

Why the sun can be seen about two minutes before actual sunrise ;

Explaination:

• The atmosphere of the Earth has various layers with varying Refractive Indices due to different composition of the layers of the atmosphere.

• Now , light rays from the Sun after entering the atmosphere undergoes refraction at every layer and finally reaches the eye of the observer.

• Once it reaches the observer , the light ray can be extended backwards to see a virtual image of the sun above the horizon.

• Hence , the sun can be seen a few minutes before the sunrise.

Refer to the attached diagram.

Answer 2

The sun can be seen about two minutes before actual sunrise because

• The density of air varies in the atmosphere i.e. in some places of atmosphere density is less and in some places of the atmosphere the density is more.  

• When the sun is below the horizon i.e.2 minutes before the actual sunrise, the sun light  is coming from the atmosphere where the density of air is less.

• When we see it from the earth where the density of air is more,then the refraction takes place.and the image is pulled backwards and hence it is seen to us like it is above the horizon.

Kindly refer to the diagram attached below

b90bb95411720b5f1a3c0ca8775ad605.docx