State what is meant by total internal reflection?

Question

3 points question
Physics o-lvel

Answer 1

in physics, complete reflection of a ray of light within a medium such aswater or glass from the surrounding surfaces back into the medium. The phenomenon occurs if the angle of incidence is greater than a certain limiting angle, called the critical angle. In general, total internal reflection takes place at the boundary between two transparent media when a ray of light in a medium of higher index of refraction approaches the other medium at an angle of incidence greater than the critical angle. For a water-air surface the critical angle is 48.5°. Because indices of refraction depend on wavelength, the critical angle (and hence the angle of total internal reflection) will vary slightly with wavelength and, therefore, with colour. At all angles less than the critical angle, both refraction and reflection occur in varying proportions.

Such atmospheric phenomena as halos and rainbows are caused by internal reflections in ice crystals and water droplets. Glass prisms can be shaped to produce total internal reflection and as such are employed in binoculars, periscopes, telescopes, and other optical instruments. Light rays may be conducted over long, twisting paths by multiple total internal reflection in glass or plastic rods or fibres.

Answer 2

Total internal reflection occurs when light hits a material's boundary (edge) in such a way that it is reflected backwards, away from that boundary and back into the material, rather than through it. In order for this phenomenon to occur, light must hit the boundary at an angle that is shallower than the "critical angle" of the two materials making up the inside and outside of the boundary.

Total internal reflection is the principle behind the use of fiber optics. Light travels down the glass or other material, hits a boundary and bounces back into the material rather than escaping from the fiber. This works as long as the angle of reflection remains low, which is why there are limits to the amount that fiber optic cables can be bent (that and they are often brittle and can break).

Answer 3

When a ray of light impinges on a thick material like a glass cube, it gets refracted at a given angle. The ratio of angle of incidence and angle of refraction is a constant for a given medium.When a series of rays impinge on the surface with gradually lessening angles , the least refracted rays come back into the original medium as though reflected. This reflection is called the total internal reflection. That is how we can see our hazy image in a transparent glass cube or cylinder

Answer 4

If a ray of light is travelling from an optically denser medium to an optically rearer medium then it has a tendency that after refraction on the interface of the two optical media it deviates further from the normal drawn on the point of incidence of the ray of the light at the interface of the two media. Now at an angle of incidence Ө in the denser medium if the refracted ray of light makes an angle of 90 degrees with the normal in the rearer medium, i.e. goes along the interface of the two media, then we say this angle Ө as the critical angle of these two media pair.

If a ray of light falls on the interface of these two media at an angle greater than the critical angle Ө in the denser medium then the ray never emerges out of the denser medium to the rearer medium, rather it reflects back to the same denser medium obeying the rules of common reflection and this phenomenon is known as total internal reflection. Here the interface of the media behaves like a mirror and there is no loss of energy in this process, hence known as TOTAL.

Mirage seen in the hot tropical countries, deserts is a classic example of total internal reflection. As the critical angle of diamond wrt air is very low due to high RI, it is very difficult for a light ray if entered inside the diamond to get out of it. Rather it gets total internally reflected many a times before emerging out and thus making diamond so glittering.

Answer 5

falling on the differntiating surface of 2 transparent media, light, a bit, is reflected and another bit is refracted.

if light gets to a lighter medium from a dense medium, it refracts with a refraction angle>incidence angle. for a certain refraction angle the light passes along the differntiating surface. this angle is called critical angle(Өc). if refraction angle>Өc, the light without refracting entirely gets reflected in the first/denser medium.this is called total internal reflection.

if the refractive index of the denser medium is μ, then
sin Өc=1/μ

Answer 6

when light ray pass through glass it refracts. the angle of refraction goes on decreasing if the angle of incidence decreases. at a particular angle of incidence, the light ray reflects back to same medium instead of refracting, though glass possess the property of refraction. this angle is called total internal reflection angle as all rays are only reflected now, and not refracted.

Answer 7

in equation form

from snells law.. we have Xsin(A)=Ysin(B) where X and Y are indices of refraction of materials a and b respectively

sin(A) = [(Y/X)sin(B)]

when the right hand side of the equation is greater than 1 then we have a total internal reflection. Theoretically, since the sine function cannot be greater than one, the light does not pass through material b.

Answer 8

Hai pLaSma, good query towards the phenomenon of light as it traverses from a denser to a rarer medium. Due to change in the speed of light in different media the phenomenon known as refraction takes place. Light travels at lower speed in denser medium and so its speed is less in water and more in air medium. So when light travels right from water to air it bends away from the normal as it gets more speed in air medium. Mathematically the refractive index of the medium (water) = speed of light in air/ speed of light in water. Thus refractive index becomes greater than 1 here it is 1.33 in case of water. To maintain this value to be constant as the angle of incidence increases the angle of refraction too has to increase correspondingly. This happens and the angle of refraction maximum possible in air medium will be 90 deg. Hence in this case the angle of incidence whose angle of refraction becomes 90 deg is defined as Critical Angle. If we increase the angle of incidence beyond this critical angle as it gives a room to do so, the angle of refraction too has to increase. But max 90 deg is already attained. So no chance of getting more than that. Hence the light rays don't have even a little bit opportunity to get refracted and so all the light energy get reflected into the denser medium namely water here. Hence the name TOTAL internal reflection. There after no more Snell's law possible. Hence the law of reflection is pronounced and so angle of incidence is equal to the angle of reflection.

Answer 9

total int. reflect'n: when light goes through any medium(medium like air, water, prism(glass),or any other viscous material) its path deviated(distracted) means it not goes strairght as it goes in air. this property of light is used to achive total internal reflection. lets suppose a light ray is going from air to a diamond(glass medium) it deviated from its path, as a result it remains inside the diamond. i must add to ur knowledge that diamond is cut in such an angle that all light comes inside the diamond get inside and make diamond sparkle that means it is due to total internal reflection in diamond.
we can achive tot.int.refl. by two ways 1. by giving a ray of light an appropriate angle so that ahen medium changes it achive tot.int. refl. 2 . by changing surface structure (as we do in diamond)

Answer 10

when light waves are passed through a sphere coated black, with a small whole at the enterance, the light gets reflected completely inside and doesn't come out