Question

Explain the formation of a mirage.

Answer 1

A mirage will generally form when the air in the atmosphere will be cool and the surface will be hot. This hot surface will warm the layer of air that is just above the surface. When the light will pass through the colder air and then the hot layer, the light gets refracted. Mirage is an example of a total internal reflection that occurs due to different atmospheric conditions.

COMPLETE STEP BY STEP ANSWER:
A mirage is a natural phenomenon that creates the optical illusion of water on the surface of the earth. Mirage can be observed only on sunny days usually while driving on a road.

Mirage is the cause of the total internal reflections of light. On a hot sunny day, the surface becomes very hot due to hot radiations received from the sunlight. The air above the surface warms due to the hot surface. Also, the air in the atmosphere is cooler than the air above the surface. Therefore, when the light from this cooler air enters the hot air above the surface, the light gets refracted. After getting refracted, the light in the hotter air undergoes total internal reflection. When the light undergoes total internal reflection, the image is formed. This image is the optical illusion that creates the illusion of water on the surface of the earth.

NOTE: Total internal reflection is the phenomenon of reflection due to which complete reflection of a ray of light takes place within a medium. The total internal reflection always occurs when the incidence angle of a ray of light is greater than the critical angle.
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