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

How many days would there be in an earth year, If a meteorite hit the Earth...

If a meteorite hit the Earth and moved it 2.41x 10 10 m closer to Venus, How many days would there be in an Earth year?

Explain galvanometer increase voltage sensitivity, Q. In a galvanometer, in...

Q. In a galvanometer, increasing the current sensitivity does not necessarily increase voltage sensitivity. Explain An interesting point to note is that raising the current sen

Motion of a rigid body, Translational : If a body goes such that its orient...

Translational : If a body goes such that its orientation does not change with respect to time then body is said to move in translational motion. ROTATION : If an object is rota

What is nucleus, What is nucleus?               It is the type of an ato...

What is nucleus?               It is the type of an atom where whole mass of the atom is supposes to be concentrated. Or it is the central part of an atom which have proton and

Resistances of resistance boxes, Are made up of alloys (manganin, constanta...

Are made up of alloys (manganin, constantan or nichrome) these materials have moderate Resistivity which is practically independent of temperature so that the specified value of re

Heat, a lead bullet moves horizontally with a velocity of 130ms and embedde...

a lead bullet moves horizontally with a velocity of 130ms and embedded into a cement wall after collision. if the specific heat capacity of lead = 130J/KgC and all heat produces is

Grouping of Capacitors, Hi Can u guide me how to solve numericals on Group...

Hi Can u guide me how to solve numericals on Grouping of Capacitors. Thanks & Regards Raj

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