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

Self Gravitational PE, Self Gravitational Potential Energy of matter formin...

Self Gravitational Potential Energy of matter forming a thin uniform shell of mass M and radius R is-

Ratio of masses of proton and electron is, Ratio of masses of proton and el...

Ratio of masses of proton and electron is: (1) Infinite (2) 1.8x10 3     (3) 1.8         (4) None of these Ans: (2) 1.8x10 3

Like and unlike pararell forces, what is the difference between like and un...

what is the difference between like and unlike pararell forces?

Degenerate and non-degenerate semiconductor, THE SEMICONDUCTOR in which num...

THE SEMICONDUCTOR in which number of electrons or holes is smaller than N c  and N v  density of state in CB or VB are called non-degenerate semiconductor. The general exponential

Wedge problems, 8. System is shown in the figure. Assume that cylinder rema...

8. System is shown in the figure. Assume that cylinder remain is contact with the two wedges. Find the speed of cylinder at the given instant cylinder

Electrostatics, the two point charges +10 nano coulomb and -20 nano coulomb...

the two point charges +10 nano coulomb and -20 nano coulomb are seperated by a distance 0.1m. calculate the neutral point along the line joining of two charges

To find current, Determine the unknown values in the following ta : ( s...

Determine the unknown values in the following ta : ( solve problems to find current, voltage, resistance  or power using ohm's law )

What is surface energy, The free surface of a liquid always has a tendency ...

The free surface of a liquid always has a tendency to contract and possess minimum surface area. If we want to enhance the surface area of the liquid, work has to be done. This wor

Explain reaction is exothermic and entropy , A chemical reaction is known t...

A chemical reaction is known to occur spontaneously under standard conditions. Which of the following statements is/are true (more than one answer may be selected): A    The to

Cylinder and sphere rolled toward a ramp, Q. Hoop, Disk, Cylinder and Spher...

Q. Hoop, Disk, Cylinder and Sphere A disk, a hoop a cylinder and a sphere have the same mass and the same diameter. Every is rolled toward a ramp with the same initial velocity

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