As we know that optics is a branch of physics that deals with the study of light and the phenomenon related to it. The phenomenon related are “ Reflection, Refraction, Dispersion, Interference, Diffraction, Total Internal Reflection, Polarization, etc.
Some of these phenomenon like diffraction, polarization, interference are explained by considering light as a wave . Phenomenon like reflection, refraction are explained by considering light as a ray.
It is the phenomena of bouncing back of light into the same medium making the same angle with the normal. So that the wavefronts return into the same medium from which it is originated for reflection the interface should be smooth, shiny, or polished. The best example is the mirror .
REFRACTION: It is the change in the direction of light while passing from one medium to another due to the gradual change in the optical density of the medium. The basic use of this phenomena is optical lenses that we use in our everyday life, its basic function is to form an image on the retina by refracting through lenses [ie: correcting our eyesight].
It is the phenomena of light in which only certain direction vibrations are allowed to pass, while rest are stopped by the polarizer. This phenomena is based on the wave nature of light. Polarization has a great significance in our everyday life as we use polaroid sheets in the windshield of cars, polaroid in optical lenses and goggles. Their basic use is to reduce the intensity of light so that there will be less strain on eyesight. Some of you must have heard about ‘RAY-BAN ‘ goggles there are having optical fiber lenses.
TOTAL INTERNAL REFLECTION [TIR]:
The phenomena of TIR is observed when light goes from denser to rarer medium and the angle of incidence is greater than the critical angle [ the minimum angle of incidence which makes the refracting angle =90 degrees ], the ray of light will reflect into the same medium. This phenomena has a lot of significance in our technological world. Some of you must have heard about optical fibers, these optical fibers are based on the phenomena of TIR
Optical fibers are synthetic fibers made up of glass in which the interior is a core made of a higher refractive index than the cladding outer surface. It is also called light pipe because like water in the pipe, a beam of light rays enters into the optical fibers and emerges out from the other end because these rays suffer the phenomena of total internal reflection. This is the best source to transmit signals without any loss of signal .
You must have heard about ‘JIO GIGA FIBRE’ the transmission of signals in this connection is based on optical fibers so there are not any losses, distortions, or any kind of weather affection. Secondly op[tical fibers also have use in ‘ANGIOGRAPHY’ ie diagnose of blockage in the arteries optical fibers are also used to get images of stomach and photographs of internal organs.
Now we can see that optics has a great ‘ significance in our everyday life’ hence I want to conclude with a with quote
“ANY SUFFICIENT ADVANCEMENT IN TECHNOLOGY IS INDISTINGUISHABLE FROM MAGIC”.