General Knowledge - Physics - Discussion

Unequal heating of different layers of atmosphere causes different temperature for different layers and as a result different densities which further adds that the speed of light will be different in these layers (layers will be having different refractive index) ie, white going higher from the surface the refractive index decreases and the layers becomes rearer and light ray going up from surface after passing each layer of atmosphere bends away from normal (because it passes from denser to rearer medium) and at a particular angle it suffers total internal reflection and comes back to the surface and falls on a person eye (this is called a mirage).

The Above Phenomenon is a great example of TOTAL INTERNAL REFLACTION, Which comes in account when light travels from denser medium to rearer medium, after some specific angle it again reflacts into the denser medium. Similar kind of activity happens in desert area called "Mirage" or "Marichica".

Mirage is on hot summer days the layer of air in contact with the sand becomes hot and rare. When the light rays travel from denser to rarer, they undergo total internal reflection. Thus image of the distant object is seen inverted.

This phenomenon is due to the fact that during days the hot air rises and cold air descends down and we know that hot air is more denser than cold one so rays are totally reflected back and therefore this phenomenon takes place.

The different layers of earth are heated differently as the air become lighter as we move upwards from earth and because of different densities of air a phenomena TIR takes place and an illusion is created.

Mirage - An optical illusion caused by atmospheric conditions, esp. the appearance of a sheet of water in a desert or on a hot road caused by the refraction of light from the sky by heated air.

A mirage is a pool of water ahead of a traveler on a hot sunny day and it is as a result of total internal. It disappears as the traveler approaches it.

Light refracting upwards results in an inferior mirage.

Light refracting downwards results in a superior mirage.

E.g. Long sight fake water on road.

Mirage is an effect caused by hot air in a desert which makes you think you can see the object when they are not actually there.

Its not only found in deserts we can come across this phenomenon in our daily life eg:sometimes we can see mirage image of tree.