Advanced Sunrise and Delayed Sunset

Did you know that we actually see the sunrise about 2 minutes earlier than the actual sunrise? Also, the sunset that we witness is of the sun that has already set? It is fascinating to learn that the position of the sun varies so much from its actual position. This is because of the phenomenon known as atmospheric refraction.

Table of Content

What Is Refraction?

The phenomenon in which the waves undergo a change in direction when it passes from one medium to another is known as refraction. The refraction of light is the most commonly observed phenomenon. Refraction of light is defined as the phenomenon in which the light bends while travelling from one transparent substance to another.

Read More: Refraction of Light

What is Atmospheric Refraction?

Atmospheric refraction is defined as the refraction of light by the earth’s atmosphere. The earth’s atmosphere has different layers with different optical densities. When an object transmits light rays in the atmosphere, the light travels through these different layers and gets refracted.

Advanced Sunrise Explanation

During sunrise, the sun is rising above the horizon. The rays from the sun get refracted as they travel from more dense air to less dense air. Also, the human eye sees the sun rays as a straight line, which appears as the sun has risen. But it has actually not yet risen.

Advanced sunrise and delayed sunset

Delayed Sunset Explanation

The sun, after sunset, is setting below the horizon. Now, the apparent position of the sun is visible to us and not the actual position. This is because of the atmospheric refraction.

Click the below link to understand why the sunsets are red

Frequently Asked Questions – FAQs


Give an example of refraction in nature.

The twinkling of stars is an example of refraction in nature.


State the laws of refraction of light.

According to the laws of refraction of light, the incident ray, the refracted ray, and the normal to the interface of the two media at the point of incidence all lie on the same plane. Also, the ratio of sine of angle of incidence to the sine of angle of refraction is a constant. This is also known as Snell’s law of refraction.


What is the refractive index?

Refractive index is used for describing how fast light travels through the material.


What happens when the white light passes through the prism?

When the white light passes through the prism, it gets divided into its components, and they are red, orange, yellow, green, blue, and violet. This is due to the refraction of light.


Give 2 applications of refraction of light.

Peepholes used in doors, cameras, and movie projectors and the spectacles are the 2 applications of refraction of light.

Watch the video and solve the previous year questions in the chapter The Human Eye and Colorful World Class 10

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  1. Thank u sir or maam ,,,,,,,, it was very usefull