what is mirage?

Answer 1

Mirage is an optical illusion caused due to Total Internal Reflection.It occurs during summers and especially in deserts.
Now, i hope u know that for a certain column of atmosphere the pressure,temprature and density increases with height from the earth's surface.So, the light rays coming from an object will suffer continuous refraction as it will move from a denser to a rarer medium to reach our eyes.Hence,the angle of incidence gets increased because the refracted rays move away from the normal. A gradual increase in the angle of refraction brings a situation where it exceeds the critical angle.Henceforth, at that level the total internal reflection occurs and the ray of light returns back in the same medium,so an image is formed which is inverted.
This is mirage, simple!

Answer 2

A mirage is a naturally-occurring optical phenomenon, in which light rays are bent to produce a displaced image of distant objects or the sky. The word comes from the Latin mirari, meaning 'to be astonished'. This is the same root as for mirror. Like a mirror, a mirage shows images of things which are elsewhere. The principal physical cause of a mirage, however, is refraction and not reflection.

A mirage is not an optical illusion. It is a real phenomenon, and one can take photographs of it. The interpretation of the image, however, is up to the fantasy of the human mind.
Cold air is denser than warm air, and has therefore a greater refractive index. As light passes from colder air to warmer air it bends away from the direction of the temperature gradient (the "normal" in the figure at right); when it passes from hotter to colder, it bends towards the direction of the gradient. The diagram on the right shows a light ray coming from the sky toward the hot ground. If the air near the ground is warmer than that higher up, the light ray bends in a concave upwards trajectory. Once the ray reaches the viewer’s eye, the eye traces it as the line of sight, which is the line tangent to the path the ray takes at the point it reaches the eye. The result is that an inferior image for the above sky appears on the ground. The viewer may incorrectly interpret this sight as water reflecting the sky. In the case where the air near the ground is cooler than that higher up, the light rays will of course curve downwards, producing a superior image.

The 'rest' state of the Earth's atmosphere is with a vertical gradient of about -1 degree Celsius per 100 metres height. (The value is negative because it gets colder when you go higher.) For an actual mirage to happen, the temperature gradient has to be much greater. According to Minnaert[1] the magnitude of the gradient should be at least 2°C per metre, and the mirage will not get strong until the magnitude reaches 4 or 5°C per metre. These conditions can occur when there is strong heating at ground level, for example when the sun is shining on sand or asphalt.

Answer 3

A mirage is a type of optical illusion. The bending of light rays (refraction) as they pass through air with different temperatures causes mirage. It generally appears in a desert. The heat makes the light rays refract as they pass from cool air down to the hot air near the ground. The rays from the cloud create a mirage on the sand. If you happen to stand in a desert you think you can see a cloud on the sand, but it is not really there. It's a mirage! The most common type of mirage is the oasis mirage when travellers sometimes see a distant oasis but when they reach the spot, they find only dry sand. A mirage may even appear when a person is driving and sees what seems to be a pool of water lying on a hot paved road ahead. But when the person reaches the spot, the water has disappeared or has moved further down the road. The Fata Morgana is one of the most beautiful of all mirages. It occurs when a layer of hot air traps rays of light coming from the distant objects. Objects such as rocks or chunks of ice appear to be towers of a fairy-tale castle.

http://www.schoolsahead.com/sscan/physics.html

Answer 4

A mirage is a naturally-occurring optical phenomenon, in which light rays are bent to produce a displaced image of distant objects or the sky. The word comes from the Latin mirari, meaning 'to be astonished'. This is the same root as for mirror. Like a mirror, a mirage shows images of things which are elsewhere. The principal physical cause of a mirage, however, is refraction and not reflection.
A mirage is not an optical illusion. It is a real phenomenon, and one can take photographs of it. The interpretation of the image, however, is up to the fantasy of the human mind.

Answer 5

Mirage is an optical illusion .........





If observed carefully we see,
A layer of water on a very hot day on the road or on the desert
A mirage is not only seen by thirsty desert wanderers.
You can also see one driving comfortably along a black top highway on a sunny day. That 'wet' looking spot on the road up ahead could actually be a mirage that stays in the distance

The hot surface warms the air immediately above it to a higher temperature than the air higher up. A light ray grazing the surface under those circumstances is bent, or refracted, upward. That's because light travels faster in warmer, less dense, air than in denser cold air. The faster motion of the lower part of a light ray speeds ahead of the upper part, causing it to bend (refract) upward.

When the refracted light ray meets your eye, it appears to be coming from the road surface instead of the distant sky. A reflected light ray follows a similar path, so the refracted ray is interpreted as a reflected one and a 'Mirage' is seen.

Answer 6

Like a mirror, a mirage shows images of things which are elsewhere.

A mirage is not an optical illusion. It is a "real phenomenon", and one can take photographs of it. The interpretation of the image, however, is up to the fantasy of the human mind.

Example:

In deserts , The real object is the (blue) sky or any distant object in that direction, meaning we see a bright bluish patch on the ground in the distance.
For exhausted travellers in the desert it appears as a lake of water. On tarmac roads it may seem that water or even oil has been spilled. This is called a desert mirage or highway mirage

Answer 7

Mirage is a make-believe illusion into a vision. Vision is real but the visionary object is unreal. During summer, everyone of us experiences this. The tar roads beyond a distance of 100 metres looks like a lake or river full of water. When we go there, no water is seen but again the same scene appears beyond some distance. This goes on continuing as long as we move on the road. The same experience is felt in the deserts. So the thing that is not physically present is visually experienced. We can also compare it to our life situations. For example, Henry Williams, a beggar, finds a mirage of becoming the President of U.S. A thing that is not existing but due to visionary dupe, we feel that is existing.

Answer 8

Mirage is formed by the phenomenon called Total Internal Reflection (TIR). When light from a denser medium enters into a rarer medium at an angle greater than the critical angle then the light is bent into the denser medium itself or in the other words, it gets reflected back. In hot summer region, the air near to the surface is denser than the air at the top and there is a varying density of the air . Light from the object while travelling up the air actually enters into the rarer region and after multiple entries it gets reflected back. In this way the image of the the object is formed and it appears below the ground. This phenomena is seen in desert region.

Answer 9

A mirage is a phenomenon where you think you see water and is very common in deserts. They happen when light passes through two layers of air with different temperatures. The desert sun heats the sand, which in turn heats the air just above it. The hot air bends light rays and reflects the sky. When you see it from a distance, the different air masses colliding with each other act like a mirror. The desert ahead seems to have become a lake but it is actually a reflection of the sky above.

Answer 10

A mirage is an optical phenomenon which often occurs naturally. The kind most commonly seen (known as inferior mirage, because the inverted image lies below the upright one) is produced by the refraction of light when it passes into a layer of warm air lying close to a heated ground surface. This is an example of gradient index optics.