Explain the formation of Mirage .

Explanation

i. In summer, the air near the hot road or desert surface has very high temperature and hence it becomes lighter than the cool air above it.
ii. As, the density of air goes on decreasing with increase in height above the surface, the refractive index of air increases.
iii. Hence, the direction of light rays coming from a distant object keeps changing according to laws of refraction.
iv. This makes the light rays coming from distant object appear to come from an image of the object inside the ground as shown in the figure. This is called mirage.

v. Thus, formation of mirage is the effect of changing refractive index in the atmosphere.
vi. An illusion of the appearance of water on a hot road or in a desert is an example of mirage.