Refractive index, Physics

Assignment Help:

Refractive index:

The most important optical measurement for any transparent material is its refractive index (n). The refractive index is the ratio of the speed of light (c) in a vacuum to the speed of light in the medium:

The speed of light in a material is always slower than in a vacuum, so the refractive index is always greater than one in the optical part of the spectrum. Although light travels in straight lines through optical materials, something different happens at the surface. Light is bent as it passes through a surface where the refractive index changes. The amount of bending depends on the refractive indexes of the two materials and the angle at which the light strikes the surface between them.

The angle of incidence and refraction are measured not from the plane of the surfaces but from a line perpendicular to the surfaces. The relationship is known as "Snells Law", which is written; ni sin I = nr sin R, where ni and nr are the refractive indexes of the initial medium and the medium into which the light is refracted. I and R are the angles of incidence and refraction.

1747_REFRACTIVE INDEX.png

Snell's law indicates that refraction can't take place when the angle of incidence is too large. If the angle of incidence exceeds a critical angle, where the sine of the angle of refraction would equal one, light cannot get out of the medium. Instead the light undergoes total internal reflection and bounces back into the medium.

Figure  illustrates the law that the angle of incidence equals the angle of reflection. It is this phenomenon of total internal reflection that keeps light confined within a fibre optic.

23_REFRACTIVE INDEX1.png


Related Discussions:- Refractive index

Scattering of light, Molecules of a medium after absorbing incoming light r...

Molecules of a medium after absorbing incoming light radiations, sends them in all direction. This process is called as Scattering.

Thermodynamic laws, Thermodynamic laws: First law of thermodynamics ...

Thermodynamic laws: First law of thermodynamics In internal energy of a system the change is the total heat transferred to or from the system & the work done on or by

What is the minimum velocity an thermosphere, Earth's atmosphere is separat...

Earth's atmosphere is separated into four layers: The troposphere (0-10 km), the stratosphere (10-50 km), the mesosphere (50-80 km), and the thermosphere (80-500 km).

Explain the behaviour of the block, Wooden block sits on a level lab table....

Wooden block sits on a level lab table. A string draped over a pulley connects to a bucket that can be filled with lead pellets. Maggie needs to measure how much applied mass (pell

Interference, Construction and working of Fabry perot interferometer

Construction and working of Fabry perot interferometer

Relativity principle, Relativity principle: The principle, employed th...

Relativity principle: The principle, employed through Einstein's relativity theories, that the laws of physics are the similar, at least qualitatively, in all of frames. That

Define potential difference, In an electric field difference among potentia...

In an electric field difference among potential energy of two points A and B is described as equal to the amount of work done (by external agent) in moving a unit positive charge f

Classes of magnetic materials: antiferromagnetism, Anti ferromagnetic mater...

Anti ferromagnetic materials such as chromium have a small but positive susceptibility. They cannot possess any magnetization is the absence of an applied field, in contrast to fer

Explain basic principle of holography, Explain basic principle of holograph...

Explain basic principle of holography Holography is a new method of producing a 3D image of a 3Dobject. An ordinary photograph is only a 2D image of a 3D object. The photograph

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd