Name: Specular and Diffused Reflection
Uploaded: 2019-07-19
Duration: 3 min 42 s
Description: In this video, we will discuss the types of reflection, such as specular and diffused reflection in detail. Let's watch and learn.

Question

What are mirage and looming?

Accepted Answer

The refractive index of air increases with its density. In hot places, air near the ground is hotter than air at a height. Hot air is less dense. Hence, in still air the refractive index of air increases with height. Because of this, light from tall objects like a tree, passes through a medium whose refractive index decreases towards the ground. Hence, a ray of light successively deviates away from the normal at different layers of air and undergoes total internal reflection when the angle of incidence near the ground exceeds the critical angle. This gives an illusion as if the light comes from somewhere below the ground. Because of the shaky nature of the layers of air, the observer feels as if the object is getting reflected by a pool of water or wet surface beneath the object as shown in the figure below. This phenomenon is called mirage.

In the cold places the refractive index increases towards the ground because the temperature of air close to the ground is lesser than the temperature above the surface of earth. Thus, the density and refractive index of air near the around is greater than at a height. Hence, an inverted image is formed little above the surface as shown in the figure below. This phenomenon is called looming.

What are mirage and looming?

Important Questions on Refraction of Light at a Plane Interface : Total Internal Reflection : Optical Fibre

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